If you've heard me speak about the frustrations I've experienced with the no-carb mentality that's sweeping the already misinformed and vulnerable over-fat nation we live in, I will not apologize for the repetition of the theme. Every single day, without exception, at least a dozen people ask me about these low-carb diets. I've counseled doctors on the dangers of these diets. I've been in touch with the heads of the American Dietetic Association, of Pritikin Longevity Centers, and with nutritional experts at Tufts and Berkeley Universities, and they share similar frustrations. People are being pulled from the truth by slick marketers of fraudulent and potentially dangerous diets and the hype is so powerful Americans are getting sucked in by the millions.
I remember a line from the movie the Exorcist (the only movie that ever really scared me by the way). When the young priest, Father Karras is preparing to go meet the possessed girl face to face, the experienced exorcist, Father Merrin warns him, "do not listen to anything the demon says. He will mix lies with the truth to confuse you."
Mixing lies with the truth has become a powerful advertising technique. If an advertiser can impress you with enough actual science, if a marketer can gain your confidence with some legitimate and well founded information, it's not very challenging to sneak in a lie and establish a level of believability. Despite the fact that in some of these low carb diet books the authors do deliver some valuable information, I'm careful not to forget the fact that they're very often offering a no-carb or very low-carb diet plan as a "cure-all" weight loss solution for the masses. Regardless of the truths anyone provides for public consumption in the future, as long as they hold tight to this "carbs are the enemy" dictum, criticism by clinicians and experts is inevitable.
Many of the no/low carb diet books almost totally dismiss exercise, and we, as trainers, know that exercise is essential if any weight loss program is going to be healthful and long term. The body treats food very differently if it is well acquainted with exercise. One important area that is also often neglected is a concern for bone density. While it is true that osteoporosis is affecting our population in alarming proportions, bone density cannot be "repaired" or "protected" through nutrition or nutritional supplementation without a distinctive concern for resistance exercise. Beyond bone density, exercise affects hormonal production in such a way that many of the best selling nutritional supplements could easily be dismissed with a simple commitment to truly supportive eating and exercise.
New diet promoters use lots of new diet jargon and often relay a word, "ketosis," as some great indicator of body fat loss. I'm going to do the best I can to explain the real story behind ketosis and some of the other effects carb deprivation can bring about.
Glycogen = Fuel
When you consume a healthful and supportive diet complete with proteins, carbs, and fats, the carbohydrates are broken down into glucose. Glucose is actually blood sugar. Some of that glucose is transported and stored in muscle tissue as "glycogen." This is sort of the fuel in your fuel tank. That's important to understand. Glycogen = Fuel.
Glycogen is used to produce energy that fuels muscle contraction. ALL muscle contraction! Don't think of muscle contraction only as exercise. Any movement requires the contraction of muscle, from blinking your eye to rising from bed in the morning. Without glycogen, you don't have any fuel in the fuel tank. As long as you're consuming carbs, you continue to re-fuel. You access and burn up stored glycogen, but quickly replace it with new muscle fuel. Understanding of that simple fact -- that carbohydrates are the source of muscle fuel -- should raise an immediate red flag toward anything that suggests eliminating or seriously limiting carbs long-term. Once you understand the basic premise behind muscle glycogen, you should understand that the liver also plays a role in fuel storage.
Some of the carbs that you eat ultimately wind up stored as liver glycogen. Think of the liver as sort of a "pump" for blood sugar. The brain burns more calories than any other organ in your body, and guess what it uses as its primary source of fuel. Glucose! Carbohydrates! As the brain results in the "burning" of blood glucose, the liver accesses its glycogen stores to keep blood glucose in adequate supply. Again, as you expend glycogen, the carbs that you ingest replete your supply.
CUT BACK THE CARBS? AT FIRST YOU'LL DO FINE . . . BUT . . .
On a carb-restricted diet, at first you're doing just fine because you have glycogen stored. After a day or two, you're using up your stored glycogen and you're not replacing it. Your body shortly thereafter begins producing ketone bodies.
Ketones are intermediaries in the process of metabolizing fat that are found in abnormal amounts in the blood and urine during periods of metabolic impairment. Give up all of your stored glycogen without replacing it and you're likely going to be in such a state (Note: if you take in too many protein calories, it is possible to avoid carbs and never enter a state of ketosis rendering the low-carb ketosis theories useless). The new diet gurus lead you to believe that the presence of these ketone bodies indicates ongoing fat release and that ketones feed the brain. That is partially true. Here are just a few issues that also need to be addressed:
- Extended periods of ketosis affect the chemical composition of the blood in such a way that you increase risk of cardiac incident (blood ketoacidosis).
- In a state of ketoacidosis, carbon dioxide accumulates in the tissues. Oxygen delivery to the cells is impaired. This can lead to a wide range of disastrous consequences ranging from respiratory ailments to metabolic illness.
- Toxic ammonia buildup resulting from severe cases of ketoacidosis can be lethal.
They also conveniently neglect to tell you that the liver is called into play to "filter" the abnormal chemicals building up in the blood. This leads to a residual buildup of uric acid. This uric acid accumulation can lead to formation of kidney stones!
Kidney stones may be common among low carb dieters, but don't mistake that for an indication that they're normal! If all is working optimally, uric acid levels stay quite manageable, the kidneys continue to function normally, and you will likely never have stones accumulating in your urinary tract.
BUT DON'T YOU LOSE WEIGHT?
It used to boggle my mind to watch people suffer as they attempt to lose weight. By depriving themselves of carbs and/or calories, they wind up lightheaded, spaced out, uncomfortable, irritable, and all around miserable . . .but when they get on the scale, there's a moment of emotional ecstasy! They're losing weight! Notice I said it "used to" boggle my mind. It doesn't any longer because suffering through potentially harmful weight loss alternatives has almost become more the rule than the exception, and I don't blame those who are victims. Most of the "victims" don't realize there is an alternative, one that truly works, and in the absence of that realization, they're primed to be suckered in by the "Diet Du Jour."
It's important to understand why you lose weight on these carb restrictive diets, and why the initial weight loss can be substantial.
Each gram of glycogen that you hold in muscle tissue attracts 2.4 grams of water, thus if you hold less glycogen in muscle due to carb restriction, it's a given there will be substantial water loss. Thus, that quick initial drop in weight among new carb restrictive diets is primarily water loss."
Recent promoters of this "carbs are evil" mentality sometimes make claims of improvements in cholesterol levels. Here I can only speak from my own experience based upon my consultations with low carb dieters in their post diet conditions: Residual Weight Gain greater than the weight lost during the diet and INCREASED LDL levels.
Some of these diets suggest you can eat anything you want as long as you avoid carbs. They ‘OK’ the consistent ingestion of red meat, of bacon, of butter, and other saturated fats. I can do a complete article on this topic alone, but I'm going to bypass it since saturated fat has been so conclusively linked to coronary artery disease, it doesn't even merit discussion here.
I have, as I mentioned, met with great numbers of these dieters, and I've found some very consistent data in understanding their adherence to the diet. They all cut out simple sugars and refined and processed flours. That's good! I encourage people to do that as it will help stabilize blood sugar and facilitate fat release . . . providing that some other aspects of nutrition are in place (not ketosis) and providing that they are involved in a supportive exercise program. Another interesting thing I found, when analyzing their food intake, is although they are told by the diet books they don't have to cut calories, in each and every case, I mean without exception . . . they are eating fewer calories than they were before the diet!
Here's why. Firstly, while butter and cream cheese and sour cream are permitted, you're not allowed to eat potatoes or bread. What in the world will you put the butter, cream cheese, and sour cream on? Most people on the most popular low carb plans have bacon and eggs for breakfast, but they stop eating the cereal. For lunch they have a cheeseburger sans the bun. Bread, cakes, pastries, and other carb foods are very calorie dense. Most Americans are filling their mouths with high carb foods, thus if you eliminate carbs, you're eliminating MOST of their caloric intake. A steak, although it is higher in fat than many carb foods, is also more water dense, thus, when you take out the carb foods, it becomes quite challenging to keep caloric intake high! It's also meaningful to note that a diet composed primarily of protein and fat will decrease appetite by two separate mechanisms. By eliminating erratic sugar intake you stabilize blood sugar, minimizing sugar-induced food cravings. And by stimulating certain amino acids to cross the blood-brain barrier in greater amounts, you develop a greater sense of satiety. That means that not only are you taking in fewer calories, but your desire for food is decreasing leading to a continual drop of caloric consumption. This is, in the real world, simply a new or revisited twist on the calorie deprivation we know fails people.
So . . . will people lose weight on these diets? Of course! It's already clear that they'll lose substantial water weight. That can account for 4-10 pounds in the very first week!
Let's look at what happens after the water loss. Remember, glucose (stored as glycogen) is the preferred source of fuel for muscle contraction. In a state of calorie deprivation combined with the absence of that preferred fuel source the body finds a way of creating its own glucose, the blood sugar that it's lacking. It can manufacture blood sugar from amino acids. Amino acids are the building blocks of proteins, and there are three of them, known as the Branched Chain Amino Acids--leucine, valine, and isoleucine--that can be simply converted into glucose. You can get these amino acids by breaking apart complete proteins and simply metabolizing the other amino acids or dismissing them from your body as waste.
If I've confused you, I want to un-confuse you. I want you to understand this. Let me make it a bit simpler. No carbs come in… Your body wants glucose so it makes its own… It uses amino acids as the raw material… To get those amino acids, it must break down either dietary protein . . . or muscle tissue!
If you are taking in enough protein for muscle synthesis, enough protein that would normally allow you to build new healthy cells, in a state of carb depletion you'll likely sacrifice some of those proteins to manufacture glucose. That gives you intake of protein below that which you need to maintain lean body mass so muscle breaks down and is not repaired. Once you've exhausted your dietary protein supply, your body goes somewhere else to find amino acids. It breaks down more muscle tissue! Since muscle is the site where fat is burned, that cripples your fat burning ability. Since muscle--as opposed to fat--is tissue that actually burns calories, this process slows metabolism. This combination of factors guarantees that when you go off of the no-carb diet, (and you will…you must - your body craves carbs for survival), you will wind up gaining back all of the weight you lost plus additional fat.
BUT . . . WE'RE ALL CARB SENSITIVE?!?!?
The new diet books throw the term "carb sensitivity" around and often claim that all Americans due to their non-supportive eating habits, have developed a case of this mysterious ailment. They therefore recommend that you throw away most carbs. Interestingly, when your body is in a state of glycogen depletion, it begins creating little enzymes, literally hunting for carbs. Some chemical and metabolic changes take place leading to greater carb sensitivity than ever! A friend and associate, one of the individuals I most respect in this field, Keith Klein (a nutritionist based out of Houston, Texas) has found - as I have - an unquestionable increase in carb sensitivity among low carb dieters.
In working with individuals who do have some challenges with even moderate carb intake, I've found it far better to gradually shift carb intake from non-supportive simple sugars and refined flours to the more supportive carbs in meals complete with proteins, vitamins, minerals, and essential fatty acids. It is then possible to slowly get a carb sensitive individual to gradually tolerate and optimize ingestion of potatoes, whole grains, and vegetables. It takes time, but in a great majority of cases I've used this method to bring about consistent improvement in metabolism and body composition (fat loss). Healthfully. Throwing carbs out completely only adds to the problem.
It appears, based on clinical research, that 10-25% of Americans do have some level of insulin resistance (carb sensitivity). Conclusive research has clearly shown that improvements in body composition (lean body mass vs. fat) and regular exercise are far more important in offsetting the challenges of insulin resistance than cutting back carbs.
Several low carb diet authors lump carbs together as "the enemy." There's no question that a gradual American shift to pretzels, Snackwell cookies, and processed bagel breakfasts has led to impaired carbohydrate metabolism in some individuals, but there's no reason to throw the baby out with the bath water. Carbohydrates are a nutrient, and nutrient, by definition, means "something your body needs to ingest to sustain life." There's obviously a flaw with any program that asks people on a massive scale to eliminate intake of a vital nutrient. With a true understanding of the differences between complex carbs and simple sugars, it becomes possible to eliminate the culprits (simple and refined sugars) and reacquaint carb sensitive individuals with supportive metabolism of high qualify valuable complex carbs (along with protein, fats, vitamins, minerals, and an optimal supply of water).
BUT . . . WON'T THIS LOW CARB PLAN HELP MY METABOLISM?
I'm amazed that so many people buy into the claim that these low-carb or no-carb diets will stimulate metabolism when I can't find a shred of evidence that lends itself toward that direction. In fact, in the absence of carbs and necessary calories, not only does one run the risk of slowing metabolism through muscle loss, but the thyroid gland also performs a neat little trick. It alters its production of the hormones T3 and T4, hormones instrumental in regulating body heat, to "protect" the body from starvation. This results in a further slowdown of metabolism and can lead to long term thyroid challenges.
I believe, because there isn't any disagreement that exercise is going to be a definite positive factor in fat reduction, fitness, health, and alleviation of disease risks, and since glycogen is fuel for muscle contraction, it's more than obvious that exercisers need ample supplies of glycogen -- fuel obtained from carbohydrates. It's important to protect metabolism so the body learns to efficiently utilize carbs as fuel, proteins for cell repair and maintenance, and essential fats for their inherent biological value as components of cells.
I can keep going. I won't. I believe by now you should have some clarity on the truth behind the Protein Diets. More than ever, people need to be educated, and I'll continue to commit my programs to delivering the fitness truth. I want to emphasize that I do not have a personal vendetta against any of the no-carb diet gurus. I would simply encourage them to take note of the risks, open their eyes to those who are experiencing health issues resulting from these diets, and attempt to refine their approach into one better founded in science.
I will also continue to endorse those who share in delivering truth and I will continually strive to unite the ground army of unrecognized fitness professionals that can be so powerful in finally helping America get fit once and for all.
I welcome your responses and feedback to this article.
A Final, Final note:
If you are concerned that the information I've provided is based solely on my opinion, I assure you I've spent years researching this. Here are some references. Throughout those years I've continued to search for legitimate research backing up anything the no-carb Protein sellers profess and I haven't been able to find it. The only legitimate medical references I've found to no-carb dieting were in cases of using a Ketogenic Diet to reduce seizures in cases of brain malformations or epilepsy, and I should note that in those cases there was often fat accumulation and a concern for elevating blood cholesterol levels:
- Entering a high Protein twilight zone. Tufts University Diet & Nutrition Letter 1996; 14(3):4-6
- Coyle, EP, Fat metabolism during exercise. Sports Sci Exch 1995; 8(6):1-6
- Coyle, EP, Coggan, AR, Hemmert WK, et al: Muscle glycogen utililization during prolonged strenuous exercise when fed carbohydrate. J Appl Physiol 1986; 61(1): 165-172
- Is pasta now on the 'out' list too? Tufts University Diet & Nutrition Letter 1995; 13(3):4-6
- Coleman, Ellen, RD, MA, MPH, Carbohydrate Unloading, The Physician and Sports Medicine. 1997, 25(2):97-98
- Low Carbohydrate, high-protein diet: the way to lose weight? University of California at Berkeley Wellness Letter, December 1992
- Centers for Disease Control and Prevention, National Center for Health Statistics, Division of Health Examination Statistics. 1996.
- Golay A; Allis AF; Morel Y; de tonic N; Tankova S; Reaven G. Similar weight loss with low or high -carbohydrate diets. Am J Clin Nutr, 1996; 63(2):174-178
- Position Statement of the American Dietetic Association: Weight Management
- Weintraub M, Long term weight control study: conclusions. Clin Pharm Ther. 1992; 51:642-646
This is a small sampling of the research material I've amassed on the topic. I have also studied hundreds of relevant articles published in the American Journal of Clinical Nutrition, International Journal of Obesity, Journal of the American Medical Association, Journal of the American Dietetic Association, etc.
I've also referenced materials from and/or conversations with many health and fitness professionals ranging from educators to nutritionists. Here's a sampling of individuals I've learned from recently in relation to the topic of Low-Carb dieting:
- Megan McCrory, Ph.D., Energy Metabolism Lab researcher, Tufts University
- Dr. James J. Kenny, Ph.D., RD, Nutritionist at the Pritikin Longevity Center in Santa Monica, California and Vice-President of the National Council Against Health Fraud.
- Ellen Coleman, RD
- Tim Patton, RD, Florida International University
- Keith Klein, nutritionist, researcher, consumer activist, Klein's Eating Management Clinic, Houston Texas
- Dr. Nancy Wellman, Florida International University
- Jim Wright, PhD, Science Editor, Weider Publications
- Jeff Feliciano, researcher, Weider Nutrition
Editors Note: In order remain politically neutral, PT on the Net Editors have modified this article from its original, removing references to specific programs and companies. We appreciate Mr. Kaplan's flexibility in this matter.