Gluconeogenesis Is Your Internal Carb Factory (Episode 13)
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Next up is Episode 13 of “The Livin’ La Vida Low-Carb Show with Jimmy Moore and we welcome you back to our fourth episode of the week in the penultimate podcast of this motivational marathon. Are you enjoying the show? Hey, let us know by leaving a comment!
As usual, Jimmy has a cornucopia of excellent information about the low-carb lifestyle and how YOU too can achieve your weight loss goals! In today’s episode, he discusses how your body actually manufactures its own carbohydrates out of the protein you consume. Freaky!
Find out what this process known of gluconeogenesis is all about and why everyone who is on a low-carb plan needs to know about this. Prepare to be educated because class is in session!
Special THANKS to the sponsors of Episode 13: CarbSmart.com, OperationFitness.com, and Weight Loss Buddy
LINKS MENTIONED IN EPISODE 13:
- OperationFitness.com
- Weight Loss Buddy
- Related blog post: “Purging The ‘Body Needs Carbs’ Ignorance”
Did you miss something Jimmy said in this episode? Click through below for a full transcript!
It’s lucky Episode 13 of “The Livin’ La Vida Low-Carb Show with Jimmy Moore” as we continue the celebration of this first week of the year 2007 with daily podcasts about the amazingly healthy low-carb lifestyle. And what a week it has been, too! I’ve already shared with you about how I started my low-carb lifestyle on New Year’s Day in 2004 and went on to lose 180 pounds. Then I revealed my 10 tips for getting started on your low-carb lifestyle the right way. Yesterday I talked about how important it is to do low-carb the right way and to be sure you do the Induction phase by the book. Today I’m gonna get a little more technical with you and discuss the biological process of how the body makes its own carbs for energy even when you don’t consume any carbohydrates at all.
Speaking of Induction, have you seen all the foods available to you during the Induction phase of low-carb over at CarbSmart.com? They’ve got a full line of delicious low-carb foods from Dixie Diner, Sylvester Stallone’s high-protein puddings, Just The Cheese Popped Cheese, La Tortilla Factory Low-Carb Tortillas, Nutiva Extra-Virgin Coconut Oil, Walden Farms Dips and Sauces, DaVinci Syrups, and so much more. They are stocked and ready to serve you with low-carb products providing excellent customer service with your satisfaction in mind. That’s CarbSmart.com.
Hollywood trainer Mike Torchia from OperationFitness.com has a heart for helping kids who struggle with a weight problem. As someone who has personally felt the pain of being obese and anorexic as a child and overcame it, Mike has developed customized programs to help children of all ages, including infants, toddlers, tweens and teenagers. With Mike’s help, your child can feel special as they get fit for life! Learn more at OperationFitness.com.
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As an ongoing student of the low-carb lifestyle, I have to admit I don’t always understand every little detail about how and why this way of eating works so well to help people manage their obesity, diabetes, and other health-related issues. But that doesn’t mean I’m just gonna throw my hands up in the air in disgust and give up trying to absorb all the information I can about livin’ la vida low-carb. Instead, hopefully I can impart to you what I have learned in easy-to-understand language that will make it crystal clear why low-carb is the fantastically miraculous nutritional approach so many of us think it is. In this episode of “The Livin’ La Vida Low-Carb Show” I want to introduce to you a vital concept in the wonderful world of low-carb that you may or may not have heard about before. The more I find out about this process, the bigger my smile gets for choosing low-carb as my permanent lifestyle change. Understanding this revolutionary concept alone about low-carb will arm you with so much knowledge that you will simply confound the enemies of low-carb living so much they’ll be left speechless! What is it? It’s that 15-letter “g” word I talked about at the end of yesterday’s podcast called gluconeogenesis! Glucosaywhatsaywhat?!?! It’s gluconeogenesis. Get used to saying it because it is a key concept in livin’ la vida low-carb. Gluconeogenesis, also known as GNG, is the body’s way of creating glucose, or sugar carbs, out of the breakdown of proteins in the liver.
Although opponents of low-carb believe you are depriving your body of important dietary elements when you don’t eat the large amount of carbohydrates their low-fat buddies want you to, gluconeogenesis blows that theory out of the water because actually your body can make its own carbs from the protein you eat. Did you know this? I dare say not many people do. Should gluconeogenesis be a part of any discussion of healthy dietary methods? I sure think so! During gluconeogenesis, blood glucose levels in the body are normalized and maintained when the glucose is synthesized in the liver. During those times when the body is not taking in any food, like while you are sleeping, gluconeogenesis goes to work in this “fasting” mode using amino acids, lactate, and glycerol to begin creating the sugar the body needs and it is regulated by hormones such as cortisol and insulin to maintain proper levels of glucose. After about one day of fasting, all of the glycogen in the liver is depleted and gluconeogenesis begins in earnest using things such as lactic acid and protein to create glucose for the body. The exciting part of gluconeogenesis is that it sets your body into fat-burning mode which we talked about in an earlier podcast this week is called ketosis where excess ketone bodies are released into the blood system, brain, heart and muscles for energy. Isn’t this an incredible process? Once you grasp the concept of gluconeogenesis, you are light years ahead of most people in understanding better about the low-carb lifestyle and what makes it so special in the realm of diet, health and nutrition. More importantly, you will have the scientific facts to throw back at the naysayers who tell you that you “need” to eat carbohydrates for your body to function right. With gluconeogenesis working for you, your body could never take in another carbohydrate ever again and still survive just fine. That’s the amazing process of gluconeogenesis defined!
Oh, but I can hear the cat calls from the so-called health “experts” now. You need to eat carbs or you’ll harm your body! How are you supposed to get any energy if you never eat carbs? People who ask these silly kinds of questions don’t want to know the truth because it will get in the way of their low-fat, high-carb agenda. They submit scare tactics like the body NEEDS carbs for energy and that restricting your carb intake makes you lethargic to alarm people. What’s with this assumption that if you don’t eat carbs your body will simply shut down? That’s so shortsighted. Now, if you stopped eating any food at all, then I would agree that the body would not last very long. But why are fat and protein getting the short shrift of the macronutrients while carbohydrates are suddenly mandatory? The truth of the matter is fat and to a lesser extent protein become your fuel source when you begin livin’ la vida low-carb. That’s so hard to explain to people who are indoctrinated with the “fat-is-bad” mantra that has been hammered down our throats for three decades. But eating fat, even the much-maligned saturated fat, is extremely healthy for you. Regarding energy on low-carb, let’s just say my first few days on low-carb wasn’t a pretty picture, but it got much better for me in less than two weeks. Then, as my weight began pouring off my body like never before, guess what happened to my energy level? Was I moping around like some Ichabod Crane weakling? HA! Not even close. Like so many other people who have been on low-carb, my body has never felt this healthy, vibrant and alive as it does today, although I eat less than 40g carbs per day which low-carb opponents believe should have me falling flat on my face. Guess what? I could literally run circles around any of these nincompoops in ANY race at ANY time because I am fit as a fiddle thanks to my low-carb lifestyle. Three years of eating this way and counting now.
This is the bottom line. What are you going to put in your mouth? The so-called health “experts” believe you need a minimum carbohydrate/fat/protein ratio of 50/35/15 and that your carbs need to be the “right” kind. If half of your food intake is carbohydrates, you’ll never be able to experience stabilized blood sugar levels regardless of the “right” or supposedly “good” carbs. But even within the context of these “good carbs,” there can be poor options for people to consider. While sugar, white flour, and processed foods are obvious carbs that need to be avoided, even the much-heralded whole grains and some fruits and vegetables need to be avoided too because of their starchy or sugary makeup. People don’t NEED carbs any more than they need a hole in their head. I suggest to anyone who believe carbs are a necessary part of life read up on all the latest scientific studies showing how healthy and effective livin’ la vida low-carb is for people needing to manage their weight and ward off diseases. It will truly astound you and you might just learn something that could save your life.
A recent survey found that half of all Americans are eating lower-carb because they realize the health benefits that come from being on a controlled-carb plan for weight loss success. Whether the media and those health “experts” ever want to admit it or not, low-carb living really is the mainstream and it’s only a matter of time before people will demand better information out of their government and health leaders in the United States. We have been lied to long enough by the special interests who have repeatedly told us that we must reduce our fat, calories and portions if we ever hope to control our weight. Hogwash! The preponderance of the evidence has shown the low-fat diet to be ineffective and even detrimental to the body while the low-carb lifestyle in study after study is being hailed as a nutritional miracle worker for defeating such catastrophic societal ailments as obesity, diabetes, cancer and so much more. That’s why I’ll be livin’ la vida low-carb for the rest of my long and healthy life!
That’s it for Episode 13 of “The Livin’ La Vida Low-Carb Show with Jimmy Moore.” You won’t want to miss tomorrow’s final episode of this special week’s worth of podcast shows when I reveal the most shocking news about low-carb you will ever hear in your entire life. This will even drop the jaws of the low-fat supporters so come back and find out what it is. Tell a friend about the show and invite them to listen to this ever-growing by leaps and bounds podcast. And as always, keep on livin’ la vida low-carb!
Popularity: 58% [?]
From over 400 pounds to 230, Jimmy Moore is 
I thank God I found your website then the podcasts. I am truly learning from a master. I can’t thank you enough for all the info you have given me to stay with the low carb lifestyle.Bravo, Jimmy, bravo!!!
You are a fine warrior in this battle, Linda, and I’m so glad to have you be a part of it all. Keep absorbing all that you can and never allow the education about livin’ la vida low-carb to stop. THANKS as always for your unrelenting support!
Jimmy thanks so much for your podcasts. This has given me ammunitiion to those naysayers who say low-carb is bad. I will just tell them my body is making GNG thank you very much! I am going to post the link to this podcasts over at Kimmer (I am a member over there thanks to you and your interview with her). I love to eat this way now and will never look back. I have lost 17 pounds since Nov 23/06 and hope to get rid of another 35 to my goal. Thanks for putting it out there and I love to read your blogs daily and check out the podcasts.
Another GREAT one Jimmy……..Thanks.
THANKS for your enthusiasm about livin’ la vida low-carb and the work I am doing with my podcast show and blogs, Angela! I’m stoked about your success and appreciate hearing that Kimkins has worked for you. Kimmer really is an amazing woman, isn’t she?
Keep at it, girl, and let me know if I can ever help you along with your low-carb lifestyle. YOU GO GET ‘EM GIRL!
I appreciate your listenership, Wanda. I was a bit concerned that a big word like gluconeogenesis would turn people off to this episode, but it is just too important a concept to NOT put out there. THANKS as always for your backing. You’re the best!
Jimmy, I think at this point NOTHING is going to turn people off to education when you are blogging.personally I didn’t know the word(THAT Blog was done before I started reading BTW!) but I figured it had to have something to do with gluco………and even I found out something new today by listening so THANK YOU!!
I keep meaning to phone the comment line ..someday I will !!
We’ll try to keep sharing stuff you haven’t heard before, Wanda! Go ahead and leave me a voicemail. I’d love to hear your voice!
If gluconeogenesis is an “internal carb factory”, then why do we need vegetables or even LC fruits? Episode 14 seems to contradict this one. Jimmy I am confused. :p
Hey Jeff,
GREAT QUESTION! But don’t be confused, my friend. There are certain low-carb foods that you can eat that are indeed good for you even though your body can make its own carbs.
It’s all about making the best choices for your body about what you put in it. If that means green leafy veggies along with that thick juicy steak, then so be it.
Keep at it, man, and NEVER GIVE UP!
LOL!
I just posted this same question at your blog BEFORE seeing your reply here!
Yeah, I like certain veggies alongside a luscious steak, cooked RARE!
Here’s some non-biased information that is definately not taken from atkins.com. If you don’t understand it then you might want to contact a right minded health professional.
Gluconeogenesis
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Gluconeogenesis is the generation of glucose from non-sugar carbon substrates like pyruvate, lactate, glycerol, and amino acids (primarily alanine and glutamine).
The vast majority of gluconeogenesis takes place in the liver and, to a smaller extent, in the cortex of kidney. This process occurs during periods of fasting, starvation, or intense exercise and is highly endergonic.
Contents
[hide]
• 1 Entering the pathway
• 2 Pathway
• 3 Regulation
• 4 External links
[edit] Entering the pathway
Many 3- and 4-carbon substrates can enter the gluconeogenesis pathway. Lactate from anaerobic respiration in skeletal muscle is easily converted to pyruvate in the liver cells; this happens as part of the Cori cycle. However, the first designated substrate in the gluconeogenic pathway is pyruvate.
Oxaloacetate (an intermediate in the citric acid cycle) can also be used for gluconeogenesis. Amino acids, after their amino group has been removed, feeds into parts of the citric acid cycle, and can thus generate glucose in this pathway.
Most fatty acids cannot be turned into glucose unless the glyoxylate cycle is used, the exception being odd-chain fatty acids, which can yield propionyl CoA, a precursor for succinyl CoA. Fatty acids are regularly broken down into the two-carbon acetyl CoA, which becomes degraded in the citric acid cycle. In contrast, glycerol, which is a part of all triacylglycerols, can be used in gluconeogenesis.
[edit] Pathway
• Gluconeogenesis begins with the formation of oxaloacetate through carboxylation of pyruvate at the expense of one molecule of ATP, but is inhibited in the presence of high levels of ADP. This reaction is catalyzed by pyruvate carboxylase.
• Oxaloacetate is then decarboxylated and simultaneously phosphorylated by phosphoenolpyruvate carboxykinase to produce phosphoenolpyruvate. One molecule of GTP is hydrolyzed to GDP in the course of this reaction. Both reactions take place in mitochondria. Oxaloacetate has to be transformed into malate in order to be transported out of the mitochondria.
• Typically, the last step of gluconeogenesis is the formation of glucose-6-phosphate from fructose-6-phosphate by phosphoglucose isomerase. Free glucose is not generated automatically because glucose, unlike glucose-6-phosphate, tends to freely diffuse out of the cell. The reaction of actual glucose formation is carried out in the lumen of the endoplasmic reticulum. Here, glucose-6-phosphate is hydrolyzed by glucose-6-phosphatase, a regulated membrane-bound enzyme, to produce glucose. Glucose is then shuttled into cytosol by glucose transporters located in the membrane of the endoplasmic reticulum.
[edit] Regulation
Gluconeogenesis cannot be considered to be a reverse process of glycolysis, as the three irreversible steps in glycolysis are bypassed in gluconeogenesis. This is done to ensure that glycolysis and gluconeogenesis do not operate at the same time in the cell, making it a futile cycle. Therefore, it is reciprocal regulated between glycolysis and gluconeogenesis. Many regulations, which inhibit glycolysis, will activate gluconeogenesis in reverse.
Glucose-6-phosphate regulates the enzyme glucose-6-phosphoratase in the lumen of ER by promoting its activity. On the contrary, its accumulation will feed-back inhibit hexokinase in glycolysis. Once again, it follows the principle of reciprocal regulation.
The majority of the enzymes responsible for gluconeogenesis are found in the cytoplasm; the exception is pyruvate carboxylase, which is located in the mitochondria. The rate of gluconeogenesis is ultimately controlled by the action of a key enzyme fructose-1,6-bisphosphatase, which also regulated through signal tranduction by cAMP and its phosphorylation.
Most factors that regulate the activity of the gluconeogenesis pathway do so by inhibiting the activity of key enzymes. However, both acetyl CoA and citrate activate gluconeogenesis enzymes (pyruvate carboxylase and fructose-1,6-bisphosphatase, respectively). Notably, AcCoA and citrate also play inhibitory roles in pyruvate kinase in glycolysis.
http://www2.ufp.pt/~pedros/bq/gng.htm
The human body has two main ways to keep constant blood glucose levels between meals: glycogen degradation and gluconeogenesis. Gluconeogenesis is the synthesis of glucose from other organic compounds (pyruvate, succinate, lactate, oxaloacetate, etc. Most of the reactions involved are quite similar to the reverse of glycolysis. Indeed, almost all reactions in glycolyis are readily reversible under physiological conditions. The three exceptions are the reactions catalyzed by :
In gluconeogenesis, every one of these steps is replaced by thermodinamically favorable reactions. Among these three reactions, phosphoenolpyruvate synthesis from pyruvate is the most energy-demanding, since its G is rather positive. In order to overcome this thermodynamic barrier, the reaction will be coupled to a decarboxylation, a strategy often used by the cell to displace an equilibrium towards the formation of products, as it will also be observed in several reactions in the citric acid cycle. Since both pyruvate and phosphoenolpyruvate(PEP) are three-carbon compounds, pyruvate must be carboxylated to a four-carbon compound, oxaloacetate (OAA), before such a decarboxylation can happen. The enzyme responsible for pyruvate carboxylation (pyruvate carboxylase) is present inside the mithocondrial matrix, and contains biotin, a CO2-activating cofactor. The energy required for the carboxylation comes from from the hydrolysis of ATP. Oxaloacetate decarboxylation releases the energy needed to enable C2 phosphorylation by GTP, yielding phosphoenolpyruvate (in a reaction catalyzed bynuma phosphoenolpyruvate carboxykinase - PEPCK)
Oxaloacetate produced by the pruvate carboxylase cannot cross the mithochodrial membrane. It can only leave the mithochondrion after conversion to malate os aspartate. The choice of the process depens on the availability of cytoplasmic NADH (needed for gluconeogenesis). If there is enough NADH in th cytoplasm (e.g. when lactate is being used as gluconeogenic substrate) oxaloacetate will be transaminated to aspartate. Otherwise, OAA will be reduced to malate in the mithochondrial matrix. The mithochondrial membrane is permeable to malate, which moves into the cytoplasm, where it can be oxidized to oxaloacetate with concommitant production of NADH. Oxaloacetate can then be decarboxylated to PEP by the cytoplasmic PEPCK. Some tissues also contain a mithochondrial PEPCK.
In gluconeogenesis, the reactions catalyzed by phosphofructokinase and hexokinase are replaced by hydrolytic reactions. Instead of phosphorylating ADP to ATP (the exact reverse of glycolysis, yet thermodynamically not favorable under physiological conditions), phosphate is released by hydrolysis:
Fructose-1,6-bisphosphatase is present in almost all tissues, but glucose-6-phosphatase is only present in liver and kidney, which allows these organs to supply glucose to other tissues:
Low-carbohydrate diet
From Wikipedia, the free encyclopedia
(Redirected from Low carbohydrate diet)
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Please help improve this article or section by expanding it.
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This article has been tagged since January 2007.
Low-carbohydrate diets or low carb diets are nutritional programs that advocate restricted carbohydrate consumption, based on research that ties consumption of certain carbohydrates with increased blood insulin levels, and overexposure to insulin with metabolic syndrome (the most recognized symptom of which is obesity).
Under these dietary programs, foods high in digestible carbohydrates (sugars and starches) are limited or replaced with foods containing a higher percentage of proteins, fats, and/or fiber.
Contents
[hide]
• 1 History
• 2 Practices and Theories
• 3 Ketosis and Insulin Synthesis: What is Normal?
• 4 Scientific studies
• 5 Arguments for low-carbohydrate diets
o 5.1 The evolutionary argument
o 5.2 The Inuit Paradox
o 5.3 Favorable studies
• 6 Arguments against low-carbohydrate diets
o 6.1 Side effects
o 6.2 Environmental impact
• 7 Food industry response
• 8 Misconceptions
o 8.1 Meat, vegetable, and fiber content of the diet
o 8.2 Water-related weight loss
o 8.3 Exercise
o 8.4 Carbohydrate intake today and in the past
o 8.5 Micronutrients and vitamins
• 9 See also
• 10 External sources
[edit] History
The history of the low-carbohydrate diet really begins with human history. The diet of early humans (the so-called paleolithic diet) was heavily skewed toward meat and fat (some groups still dispute this[1] but most anthropologists and biologists agree on this point).[2][3][4] The shift toward a more carnivorous diet allowed humans to obtain calories more efficiently and to develop larger brains. The species did continue to eat plants as its ancestors had but as evolution progressed the human digestive tract could no longer derive sufficient nutrition from most of the readily accessible plants in the natural environment. As a result of the Agricultural Revolution, whereby most of the plants and that humans eat today have been developed by humans through cultivation and breeding, plants can now cover the majority of human nutritional needs.
The Agricultural Revolution marks the invention of agriculture, which allowed for the developing of crops that could provide greater nutrition than was previously possible (mostly in the form of starch), and developing cooking techniques to make the crops more edible. This innovation gradually converted human societies from almost exclusively meat-eating societies to societies that ate diets which were mixtures of meat and plants. On an evolutionary timescale, the technological capability to sustain life with a vegetarian diet is very recent.
The beginning of the modern history of low-carbohydrate diets is popularly attributed to William Banting and and Dr. William Harvey[5] (before this, though, anecdotal and holistic prescriptions, containing passages about limiting certain foods, including foods of mostly carbohydrates, have appeared throughout history). Banting was an overweight undertaker who developed hearing difficulties. He sought the help of Dr. Harvey who diagnosed his hearing difficulties as being directly related to his weight problem (his fat was pressing against his inner ear). He prescribed a diet that was very much like the low carbohydrate diets of today (which indicates this diet was, at least informally, known to be effective even at that time). Banting lost weight and his health problems disappeared. This led to Banting’s publication of the book Letter on Corpulence in 1869, the first modern low-carbohydrate diet book. The mainstream thinking, though, formalized by the invention of the concept of the calorie in the late 19th century, was still that weight control was primarily a matter of controlling the amount of food consumed.
In the 1920s, Johns Hopkins Medical Center developed the high-fat, low-carbohydrate ketogenic diet for the treatment of epilepsy. This diet was found very effective in treating many forms of epilepsy. As drug therapies were later developed this treatment gradually fell out of favor (although notably it has always been one of the treatments used by Johns Hopkins[6]).
In 1926, Dr. Clarence Lieb published a case study on anthropologist and explorer Vilhjalmur Stefansson who lived for years with the Inuit consuming a diet that was almost entirely meat and fat. Despite expecting to find serious health problems Lieb had found Stefansson (like the Inuit) to be in perfect health showing no adverse effects from his diet. Later, during World War II the medical department of E. I. DuPont hired Dr. Alfred Pennington to help address weight problems with many of the employees.[6] After some study and experimentation Dr. Pennington determined (partly inspired by previous research at the Russel Sage Institute) that the key to weight loss was not restricting consumption overall but reducing consumption of carbohydrates and increasing consumption of proteins and fats. The diet he developed came to be known as the Dupont Diet. During the 1950s studies such as Kekwick and Pawan, 1956[7] and Mackarness et al., 1958 continued to demonstrate the effectiveness of carbohydrate restriction and the ineffectiveness of calorie restriction.
Mainstream science still favored the idea of calorie restriction. In addition, research by Ancel Keys starting in the 1950s led ultimately to the publication of Seven countries: a multivariate analysis of death and coronary heart disease in 1980 which linked consumption of cholesterol and saturated fats to heart disease. This research led to the contemporary low-fat diet trend and discouraged research into low-carbohydrate diets. It should be noted that Keys’ theory was not universally accepted when published originally, Dr. George Mann being a noted detractor.[8]
Despite this low-carbohydrate diets such as the Air Force Diet[9] (referred to by some as the first real “low carb” diet) and the Drinking Man’s Diet[10] had brief periods of popularity in the 1960s. In 1972, Dr. Robert Atkins published Dr. Atkins Diet Revolution which advocated a low-carbohydrate diet he had successfully used in treating thousands of patients in the 1960s.[11] Like its predecessors the book met with some success but, because of research at that time demonstrating risk factors associated with excess fat and protein, it was very widely criticized by the mainstream medical community as being dangerous and misleading thereby limiting its appeal at the time. Among other things critics pointed out that Dr. Atkins had done little real research into his theories and based them mostly on annectdotal evidence. Dr. Atkins nevertheless continued to develop his theories and gain followers. During the 1980s and 1990s the obesity epidemic in the United States blossomed in spite of the popularity of low-fat diets thereby leading many doctors to question the efficacy of this approach. The concept of the glycemic index was invented in 1981 by Dr. David Jenkins.[12] This and subsequent research demonstrated that many complex carbohydrates can be as harmful as sugars. In the 1990s Dr. Atkins published Dr. Atkins New Diet Revolution and other doctors (and later celebrities and health gurus) began to publish books based on the same principles. This can be said to be the beginning of the “low carb craze.”[13]
During the late 1990s and early 2000s low-carbohydrate diets became some of the most popular diets in the U.S. (by some accounts as much as 18% of the population was using a low-carbohydrate diet at its peak[14]) and spread to many countries. These were, in fact, noted by many food manufacturers and restaurant chains as substantially affecting their businesses (notably Krispy Kreme[15]). This was in spite of the fact that the mainstream medical community continued to vehemently denounce low-carbohydrate diets as being a dangerous trend.[16][17][18] It is, however, valuable to note that many of these same doctors and institutions at the same time quietly began altering their own advice to be closer to the low-carbohydrate recommendations (e.g. eating more protein, eating less starch, reducing consumption of juices by children[19]). The low-carbohydrate advocates did some adjustments of their own increasingly advocating controlling fat and eliminating trans fat. It is also valuable to note that most of major medical groups have acknowledged at least that the low-carbohydrate diet is effective in the short-term. Many of the diet guides and gurus that appeared at this time intentionally distanced themselves from Atkins and the term low carb (because of the controversies) even though their recommendations were based on largely the same principles (e.g. the Zone diet). As such it is often a matter of debate which diets are really low-carbohydrate and which are not. The 1990s and 2000s also saw the publication of an increased number of clinical studies regarding the effectiveness and safety (pro and con) of low-carbohydrate diets (notably a 2006 NEJM paper by Halton et al. describing a study). After 2004 the popularity of this diet trend began to wane significantly although it still remains quite popular.
[edit] Practices and Theories
The term low-carbohydrate diet today is most strongly associated with the Atkins Diet. However, there is an array of other diets that share to varying degrees the same principles (e.g. the Zone Diet, the Protein Power Lifeplan, the South Beach Diet). As mentioned above there have been diet recommendations that follow the same principles in existence since before the twentieth century. As such it is difficult to summarize all of these diets and draw a sharp distinction between these and other diets. There is, therefore, no widely accepted definition of what precisely consistutes a low-carbohydrate diet. For the purposes of this discussion, we focus on diets that reduce (nutritive) carbohydrate intake sufficiently to dramatically reduce or eliminate insulin production in the body and to encourage ketosis (production of ketones to be used as energy in place of glucose).
Although originally low-carbohydrate diets were created based on annecdotal evidence of their effectiveness, today there is a much greater theoretical basis on which these diets rest. The key scientific principle which forms the basis for these diets is the relationship between consumption of carbohydrates and their effects on blood sugar (i.e. blood glucose) and hormone production. Blood sugar levels in the human body must be maintained in a fairly narrow range to maintain health. The two primary hormones related to regulating blood sugar levels, produced in the pancreas, are insulin, which lowers blood sugar levels, and glucagon, which raises blood sugar levels. In general, most western diets (and many others) are sufficiently high in nutritive carbohydrates that virtually every meal causes substantial insulin production and shuts down ketosis which causes excess calories in the diet to be stored as fat (discussed in the next section). By contrast, low-carbohydrate diets, or more properly, diets that are very low in nutritive carbohydrates, discourage insulin production and tend to cause ketosis which, according to some, can actually cause excess dietary calories as well as excess body fat to be eliminated from the body. Although these diets remain controversial there are clinical studies related to their effectiveness.[20][21]
Low-carbohydrate diet advocates in general recommend reducing nutritive carbohydrates (commonly referred to as “net carbs,” i.e. total carbohydrates reduced by the non-nutritive carbohydrates) to very low levels. This means sharply reducing comsumption of desserts, breads, pastas, potatoes, rice, and other sweet or starchy foods. Some recommend levels as low as 20-30 grams of “net carbs” per day, at least in the early stages of dieting (for comparison, a single slice of white bread may contain 15-25 grams of carbohydrate, almost entirely starch). The diets often differ in the specific amount of carbohydrates allowed, whether certain types of foods are preferred, whether occasional exceptions are allowed, etc. Generally they all agree that processed sugar should be eliminated, or at the very least greatly reduced, and similarly generally discourage heavily processed grains (white bread, etc.). They vary greatly in their recommendations as to the amount of fat allowed in the diet although the most popular versions today (including Atkins) generally recommend at most moderate fat intake.
As a related note, there is a set of diets known as low-glycemic-index diets (low-GI diets) or low-glycemic-load diets (low-GL diets), in particular the Low GI Diet by Brand-Miller et al.[22]. In reality, low-carbohydrate diets are, literally speaking, low-GL diets (and vice versa) in that they specifically limit what contributes to the glycemic load in foods. In practice, though, the diets that call themselves low-GI/low-GL diets differ from those calling themselves low-carbohydrate diets in the following ways.
1) Low-carbohydrate diets treat all nutritive carbohydrates as having the same effect on metabolism and generally assume that their effect is independent of other nutrients in food. Low-GI/low-GL diets base their recommendations on the actual measured metabolic (glycemic) effects of the foods eaten.
2) As a practical matter, the so-called low-GI/low-GL diets generally do not recommend diets with glycemic loads low enough to minimize insulin production and induce ketosis whereas the so-called low-carbohydrate diets generally do.
Another related diet type, the low-insulin-index diet, is very similar except that it is based on measurements of direct insulemic responses to food rather than glycemic response. Although the diet recommendations mostly involve lowering nutritive carbohydrates, there are some low-carbohydrate foods that are discouraged as well (e.g. beef).[23]
[edit] Ketosis and Insulin Synthesis: What is Normal?
At the heart of the debate about most low carbohydrate diets are fundamental questions about what is a “normal” diet and how the human body is designed to operate. These questions can be summarized as follows. Nutritive carbohydrates (starches and sugars) in the diet tend to break down very easily into glucose in the bloodstream (blood sugar) when consumed. Glucose in the blood is used by the cells in the body for energy for their basic function. Excessive amounts of glucose in the blood are toxic to the human body (the reason diabetes causes such serious health problems). In general, unless a meal is very low in starches and sugars the level of glucose will tend to rise to potentially dangerous levels. When this occurs, the pancreas automatically produces insulin to cause the liver to convert glucose into glycogen (glycogenesis) and triglycerides (which can become body fat), thus reducing the blood sugars to safe levels. Diets with a high starch/sugar content, therefore, cause sharp spikes in insulin production. As such the blood sugar levels are highly variable with every meal.
By contrast, if the diet is very low in starches and sugars (low-carbohydrate diets) the blood sugar level can fall so low that there is insufficient glucose to fuel the cells in the body. This state causes the pancreas to produce glucagon. Glucagon causes the conversion of stored glycogen to glucose and, once the glycogen stores are exhausted, causes the liver to synthesize ketones (ketosis) and glucose (gluconeogenesis) from fats and proteins. Most cells in the body can use ketones for energy instead of glucose and, since ketones are easier to produce, only a small amount of glucose is created (in other words, ketosis is the more significant process in this case). Because diets low in starches and sugars do not tend to directly affect blood sugar levels significantly, meals tend to have little direct affect on insulin levels (and so such diets tend to discourage insulin production in general).
The diets of most people in modern, so-called western nations, especially the United States contain significant amounts of starches (and, frequently, significant amounts of sugars). As such, the metabolisms of most westerners tend to operate outside of ketosis and tend to involve significant insulin production. This has been regarded by medical science in the last century as being “normal.” Ketosis has generally been regarded as a dangerous (potentially life-threatening) state which unnecessarily stresses the liver and causes destruction of muscle tissues. The view that has been developed is that getting calories more from protein than carbohydrates causes liver damage and that getting calories more from fats than carbohydrates causes heart disease. This view is still the view of the majority in the medical and nutritional science communities.
Most advocates of low-carbohydrate diets (specifically those that recommend diets similar to the Atkins Diet) argue that this metabolic state (using primarily blood glucose for energy) is not normal at all and that the human body is, in fact, designed to function primarily in ketosis. They argue that high insulin levels can, in fact, cause many health problems, most significantly, fat storage and weight gain. They argue that the purported dangers of ketosis are unsubstantiated (some of the arguments against ketosis result from confusion between ketosis and ketoacidosis which is a related but very different process). They also argue that fat in the diet only contributes to heart disease in the presence of high insulin levels and that if the diet is instead adjusted to induce ketosis, fat and cholesterol in the diet are not a major concern (although most do not advocate unrestricted fat intake and do advocate avoiding trans fat). Further, whereas insulin in the bloodstream causes storage of calories, when the body is in ketosis, excess ketones (which contain excess calories) are excreted in the urine and the breath. Many argue, on this basis, that the ketosis offers a so-called metabolic advantage in that the body automatically eliminates calories that it does not need even with a high-calorie diet (this argument has not yet been explicitly demonstrated by any clinical studies).
This debate is on-going and no general consensus exists at this time.
[edit] Scientific studies
Main Article: Medical research related to low-carbohydrate diets
Because of the substantial controversy regarding low-carbohydrate diets and even disagreements in interpreting the results of specific studies it is currently difficult to objectively summarize the research in a way that reflects scientific consensus.
Although there has been some research done throughout the twentieth century, most directly relevant scientific studies have occurred in the 1990s and early 2000s and, as such, are relatively new. Their results are still debated in the medical community. Supporters and opponents of low-carbohydrate diets frequently cite many articles as supporting their positions (sometimes the same articles). It is worth noting that one of the fundamental criticisms of those who advocate the low-carbohydrate diets has been the lack of long-term studies evaluating their health risks. However, in 2006, Halton et al. published a 20-year study regarding the risk of cornary heart disease for practitioners of low-carbohydrate diets (the study concluded that for the group studied, at worst, there was no increased risk of heart disease).[24]
Apart from studies addressing weight loss and heart disease, there are studies that suggest possible benefits of low-carbohydrate diets for diabetes[25], cancer[26], epilepsy[6], autism[27] , and other health problems. Such conclusions, though, are not widely accepted at this time.
For more information about studies available on these diets see the main research article.
[edit] Arguments for low-carbohydrate diets
[edit] The evolutionary argument
The Paleolithic diet did not include grains, starches, and refined sugar[28], and the human body has not evolved significantly since the time of the Neolithic Revolution, implying that their consumption should still be avoided today and causes undesired and largely unknown effects. Specifically, they cause the body to produce excess amounts of the hormone insulin, which tells the body to store rather than burn fat, hence causing obesity and its complications (heart disease, cancer, Type 2 diabetes). Humans evolved to eat a diet which consisted mainly of meat and that the current “epidemic” of obesity is due to the popular assumption, reinforced by the food industry and the new field of dietary medicine, that the low-fat approach is healthier.
Supporters claim the exclusive focus on reducing fat is oversimplified, and that low-fat diets are not automatically healthy ones. They claim that the western world is not suffering from a collective failure of will to exercise, but has been encouraged to eat more carbohydrates, which in turn stimulate appetite and more eating. Some go so far as to suggest that if the human body were truly as fragile and susceptible to illness due to small variations in diet as many doctors and dieticians have been suggesting, the species could never have survived its more primitive days. They argue that the fact that industrialized nations (notably the U.S.) are showing such an epidemic of health problems indicates that some fundamental and important aspect of the diet among these people is drastically different from early humans (and indeed the intake of sugars and starches certainly qualifies as a big difference). Conversely, early human lifespans were much shorter, and little is known about the specific diets, overall wellness or quality of life of those early humans.
The recent rise in western obesity rates has coincided with a widespread belief in low-fat, high-carbohydrate as a healthy way of eating. By contrast, traditional high-fat French cooking has led to a much lower incidence of obesity, morbid obesity and chronic heart disease than the high-sugar American diet, despite overall energy intake and exercise levels being the same.
[edit] The Inuit Paradox
Vilhjalmur Stefansson, a Canadian Arctic explorer and ethnologist, is a figure of considerable interest in dietary circles, especially those with an interest in very low-carbohydrate diets. Stefansson documented the fact that most Inuit lived on a diet of about 90% meat and fish, often going 6-9 months a year on nothing but meat and fish–essentially, a zero-carbohydrate diet. He found that he and his fellow European-descent explorers were also perfectly healthy on such a diet. When medical authorities questioned him on this, he and a fellow explorer agreed to undertake a study under the auspices of the Journal of the American Medical Association to demonstrate that they could eat a 100% meat diet in a closely-observed laboratory setting for the first several weeks, with paid observers for the rest of an entire year. The results were published in the Journal of the AMA, and both men were perfectly healthy on such a diet, without vitamin supplementation or anything else in their diet except meat.
[edit] Favorable studies
Advocates point to scientific trials demonstrating the efficacy and safety of low carb diets. Several independent clinical trials have shown that low carb diets can be successfully used to lose weight. These trials found that, in the short term, risk factors for heart disease and Type 2 diabetes — such as blood serum cholesterol and insulin levels — tended to improve in spite of increased consumption of saturated fat and cholesterol. The trials were of short duration, and were not able to assess the long-term health effects of the diet.
A study conducted in 1965 at the Oakland (California) Naval Hospital used a diet of 1000 calories per day, high in fat and limiting carbohydrates to 10 grams (40 calories) daily. Over a ten-day period, subjects on this diet lost more body fat than did a group who fasted completely. (Benoit et. al. 1965). Some advocates of low-carbohydrate diets have termed this the metabolic advantage of such diets.
Major research can be found at http://www.nutritionj.com/content/3/1/9
[edit] Arguments against low-carbohydrate diets
In 2004, the Canadian government ruled that foods sold in Canada could not be marketed with reduced or eliminated carbohydrate content as a selling point because reduced carbohydrate content was not determined to be a health benefit, and that existing “low carb” and “no carb” packaging would have to be phased out by 2006. This is not an “argument against low carb diets” but is instead marketing regulatory action intended to avoid abuses. Low-fat and low-salt labelling continues to be allowed under these regulations.
[edit] Side effects
Critics contend that low carbohydrate diets are not without harmful side effects. The lowered intake of dietary fiber that often accompanies dramatically reduced carbohydrate intake can result in constipation if not supplemented. For example, this has been a criticism of the Induction stage of the Atkins diet (note that today the Atkins diet is more clear about recommending a fiber supplement during Induction).
Increased consumption of animal-based products may lead into high consumption of saturated fat and cholesterol, which some dieticians claim will increase the risk of heart disease. Moreover, it has been hypothesized that a diet related change in blood acidity can lead to bone loss[citation needed]. This hypothesis, however, is incorrectly based on a common confusion between ketosis and the related process, ketoacidosis, as mentioned earlier in this article. One of the telltale signs of diet consisting on too little fat and too much protein is noticeable smell of ammonia in the urine.
Cutting out carbohydrates may mean missing out on vital nutrients from healthy carbohydrate foods which should be part of any well-balanced diet, especially those from fruits, vegetables and whole grains. If you’re considering a low-carb diet for weight loss, remember to make sure you get enough nutrients. Most low-carb diets emphasize intake of carbohydrates as fresh vegetables instead of cereals and bakery products.
[edit] Environmental impact
Since changes in habit of 6 billion people over a long term totals up to an enormous amount of food, it should be noted that the growth in global population over the last few centuries was only possible because of grain crops. Poor quality pasture has traditionally been fit only for raising livestock and that it has been turned to grain production only through massive government subsidies, fertilizers and pesticides.
Raising livestock instead of eating vegetable food has poor energy efficiency - around 3% of the intake of energy consumed by livestock can be employed from animal-based food. However, meat and dairy products are enriched on proteins and other nutrients. It is often also more economical to raise cattle instead of attempting to harness the area on grain production, especially when the climate conditions strongly disfavour grain and human consumable vegetables. Moreover, pasture needs less fertilization, pesticides and cultivation than grain fields and their environmental impact is likely to be less than same area of grain fields.
It must be pointed out too that parts of the above argument imply that a low-carbohydrate diet must be high in meat consumption, especially ruminants. Although certainly this is common among many practitioners of the low-carbohydrate diets few if any mainstream guides for this diet say that this is a requirement (e.g. a diet which concentrates on soy and/or fish can be quite low in carbohydrates, and fat for that matter, without requiring raising more land animals).
[edit] Food industry response
Food producers have ascribed a commercial impact to the growing popularity of low-carbohydrate diets in recent years. For example, in May 2004, New World Pasta filed for bankruptcy protection, claiming that low-carbohydrate diets were reducing demand for pasta. In the same month, Krispy Kreme Doughnuts warned investors that its earnings would be below projections, and blamed reduced demand for its products on low-carbohydrate diets.
Other producers have taken advantage of the trend. In response to consumer demand for low-carb foods, the food industry has been marketing low-carb products in recent years and restaurants are increasingly offering low carb menus. These items typically replace carbohydrate-laden wheat flour with high-protein soy flour and replace sugar with artificial sweeteners such as sucralose and sugar alcohols.
[edit] Misconceptions
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The low-carbohydrate diet trend has generated a great deal of controversy which has spawned many myths and misconceptions.[29][30][31]
[edit] Meat, vegetable, and fiber content of the diet
Some practitioners of low-carbohydrate diets may choose to eat high proportions of beef and sausage in their diets and, indeed, most low-carbohydrate diet experts (though not all) allow for more liberal consumption of fatty meats than some other diets. However, most of the main low-carbohydrate diets tend to encourage consumption of poultry and fish and similar types of meat in higher proportions than beef and more fatty pork products. It is, in fact, worth noting that a vegetarian diet is possible although this generally requires soybean products (e.g. tofu) as staples of the diet (other types of beans generally have too much starch to be acceptable as primary sources of protein).
A low-carbohydrate diet can contain vegetables, although many of the most popular vegetables in English-speaking countries are less suitable due to their high starch and/or sugar content (e.g. potatoes, corn, rice, etc.). However, there is a wide variety of vegetables that are low in sugar and starch (e.g. spinach, cauliflower, broccoli, green beans). Indeed most of the major low-carbohydrate guides strongly advocate balancing one’s diet with a healthy proportion of vegetables.
Many low-carbohydrate diets closely limit fruits in general because most fruits have a significant sugar content. These diets typically, though, do not outlaw fruits entirely. As a general rule, nutrients available in sugar-rich fruits are readily available in other vegetables as well so reduction of fruit consumption does not have to imply limiting consumption of important nutrients.
The older (pre-Atkins) low-carbohydrate diet guides focused on refined sugars and starches as the primary concerns, not carbohydrates in general. When Dr. Atkins’ Diet Revolution was first published in 1972 the book demonized all carbohydrates as unhealthy including fiber. Since that time, especially as the concept of the glycemic index was defined and developed, it has been recognized that fiber and some other carbohydrates such as sugar alcohols are not metabolized by the human body and, therefore, do not contribute to blood sugar and do not significantly trigger insulin production. Furthermore the health benefits of fiber have been recognized leading Atkins and others to modify their recommendations to distinguish between “bad carbs” (starch and sugar) and other carbohydrates (e.g. fiber). This has lead to the term “net carbs”, another name for “bad carbs”, so-called because it is typically calculated as the total amount of carbohydrates reduced by the amount of carbohydrates that are not metabolized. As such, the term “low-carbohydrate” today is really somewhat of a misnomer since most of these diets no longer strictly advocate eliminating all types of carbohydrates.
[edit] Water-related weight loss
In the first week or two of a low-carbohydrate diet a great deal of the weight loss comes from eliminating water retained in the body (many doctors say that the presence of high levels of insulin in the blood causes unnecessary water retention in the body[32]). However, this is a short-term effect and is entirely separate from the general weight loss that these diets can produce through eliminating excess body fat.
[edit] Exercise
Arguments have been made that low-carbohydrate diets inherently cause weakness or fatigue[33] giving rise to the assumption by some that low-carbohydrate dieting cannot involve an exercise regimen. Advocates of low-carbohydrate diets generally dispute any suggestion that such diets cause weakness or exhaustion (except in the first few days) and indeed most highly recommend exercise as part of a healthy lifestyle.[32]
[edit] Carbohydrate intake today and in the past
The human diet has changed significantly through history and, as such, assertions that the diets that most humans eat today are representative of the diets humans have always eaten are, at best, exaggerations. It is well established that just in the twentieth century, the consumption of sugar per capita in the U.S. and the U.K. has steadily and dramatically increased.[34] Starch consumption has increased as well. Moreover it is well known that early humans ate diets that were heavily meat-based[35] and that the shift toward high levels of starch and sugar consumption occurred much later. The current trend toward very high-carbohydrate, low-fat diets in the West is, in reality, a quite recent trend owing in large part to the research of Ancel Keys.
[edit] Micronutrients and vitamins
The major low-carbohydrate diet guides generally recommend multi-vitamin and mineral supplements as part of the diet regimen which may lead some to believe that these diets are nutritionally deficient. The primary reason for this recommendation is that if the switch from a high-carbohydrate to a low-carbohydrate, ketogenic diet is rapid, the body can temporarily go through a period of adjustment during which the body may require extra vitamins and minerals (the reasons have to do with the body’s releasing excess fluids that were stored during high-carbohydrate eating). In other words, the body goes through a temporary “shock” if the diet is changed to low-carbohydrate dieting quickly just as it would changing to a high-carbohydrate diet quickly. This does not, in and of itself, indicate that either type of diet is nutritionally deficient.
It should be noted that, contrary to the recommendations of most diet guides, some individuals choose to avoid vegetables altogether in order to minimize carbohydrates. It is more likely[citation needed] that such a diet could be nutritionally deficient (some would dispute this based on cases like Vilhjalmur Stefansson). Regardless of the truth in that regard, the choices of some individuals should not be confused with the recommendations of major experts and guides.
Hi
Very interesting information! Thanks!
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