NutritionWeight Loss Specialist

Myths of Weight Management: The High-Protein/Low-Carbohydrate Diet

Probably more widely debated than any other diet in scientific and consumer literature is the high-protein/low-carbohydrate diet. These plans have been a part of diet lexicon since the mid-1800s, with William Banting’s Letter on Corpulence (2). Billed as the “world’s first diet book,” Banting’s work recommended eating lots of meat, a few vegetables, and avoiding foods that he previously overconsumed.

Today the term “low-carb diet” is often thought of 
as synonymous with the Atkins diet, named after cardiologist Dr. Robert Atkins. Also known as just “Atkins,” the diet restricts carbohydrate consumption by eliminating most carbohydrates (rice, bread, pasta) and replacing them with meats, poultry, eggs, and dairy products (3). During the late 1990s and early 2000s, low-carbohydrate diets became some of the most popular diets in the U.S., and versions of this diet (the Zone Diet, Protein Power Lifeplan, Go Lower Diet, and South Beach Diet, among others) remain popular today. In most formats, the carbohydrate-modified (low-carbohydrate/high-protein) diet is a ketogenic diet, which induces a state of ketosis through severe limitation of dietary carbohydrates. Ketosis occurs in metabolism when the liver converts fat into fatty acids, and ketones (the byproduct of incomplete fat metabolism) reach high levels in the blood (4).

A compendium of research has examined the manipulation of macronutrient content to
produce a “metabolic advantage” for weight loss. However, there is no consensus in the literature that low-carbohydrate diets produce significantly greater rates of weight loss or longer-term weight loss maintenance when compared with more conventional low-fat diets (5-7). Additionally, the American Heart Association warns people that the high protein and saturated fat content of the Atkins diet can be harmful to the heart.

If high-protein diets produce a greater amount of weight loss in some studies, what are the possible mechanisms? Scientists suggest that several mechanisms may be responsible for the weight loss seen with low-carbohydrate diets:

  • The severe restriction of carbohydrate depletes glycogen (stored carbohydrate) supply, leading to excretion of bound water.
  • The ketogenic nature of the diet may suppress appetite, leading to reduced caloric intake.
  • The high protein content of low-carbohydrate diets may provide greater hormonally mediated satiety, thereby reducing spontaneous food intake.
  • The self-selection from limited food choices may lead to a decrease in caloric intake.

In a review article of 107 published research studies designed to evaluate changes in weight among adults using low-carbohydrate diets in the outpatient setting, Bravata (8) found that weight loss while using low-carbohydrate diets was principally associated with decreased caloric intake and increased diet duration, but not with reduced carbohydrate content. In other words, the calorie reduction and negative energy balance that occurs on these diets induce weight loss. It is worth noting that many studies in this area are limited by a high attrition (drop-out rate) and by lack of adherence to the diet.

Where does this leave health and fitness professionals with regard to low-carbohydrate diets and questions from clients? The acceptable macronutrient distributions range (AMDR) is 45% to 65% of total calories from carbohydrates. According to science supporting the AMDR, anyone eating an adequate energy provision for weight loss from nutrient-dense foods, with 45% to 65% of total calories from carbohydrates, will fall inside of the recommendation.

That said, the emphasis of nutrition counseling today is to preserve (as much as possible) the way clients like to eat. Weight loss requires habit changes, but behaviorists who specialize in weight loss suggest that if client preferences can be preserved, they should be. In other words, if a client loves sweet potatoes, whole-grain bread, oatmeal, and legumes (all nutrient-dense carbohydrates), they may not be very compliant with a program that provides only 45% of total calories from carbohydrates. They also do not need to be on a low-carbohydrate diet to lose weight, as any reduction in calorie intake below daily expenditure will induce weight loss.

Low-carbohydrate diets may work for some people, and as long as the diets are within the AMDR and provide nutrient-dense foods, they should not present a health risk. But they are not for everyone. Flexibility on behalf of the counselor and client is crucial to weight loss success (9, 10). In other words, the difficulty for most people lies not in the diet, per se, but in adherence to the diet. The closer the weight loss program is to the way clients like to eat, the more successful they are going to be. Alternatively, clients can choose to simply decrease the frequency of meals, portion sizes of the foods they normally consume, high-fat/energy-dense foods, or make any acceptable dietary changes to reduce caloric intake.



  1. Kantrowitz B and Kalb C. Diet Hype: How the media collides with science. Newsweek. March 13, 2006.
  2. Banting W. Letter on Corpulence, 1863. USA: New York: Cosimo Classics; 2005.
  3. Astrup A, Larson TM, Harper A. Atkins and other low-carbohydrate diets: hoax or 
an effective tool for weight loss. Lancet. 2004; 364:897-9.
  4. Whitney E & Rolfes SR Eds. Understanding Nutrition. 11th ed. Belmont, CA 
Thomson Higher Education; 2008, p.113
  5. Eisenstein J, Roberts SB, Dallal G, Saltzman E. High protein weight loss diets: Are they safe and do they work? A review of the experimental and epidemiological data. Nutrition Reviews. 2002; 60:189 — 200.
  6. Pittas SG, Roberts SB. Dietary composition and weight loss: Can we individualize dietary prescriptions according to insulin sensitivity and secretion status? Nutrition Reviews. 2006; 64:435-448.
  7. Schoeller, DA, Buchholtz AC. Energetics of obesity and weight control: Does diet composition matter? J Am Diet Assoc. 2005;105 (5):S24 — S28.
  8. Bravata DM, et al. Efficacy and safety of low-carbohydrate diets: a systematic review. JAMA. 2003;289(14):1837-50.
  9. Nonas CA, Foster G. Setting achievable goals for weight loss J Amer Diet Assoc. 2005; 105:(S118 — S123).
  10. Reeves R, Bolton, MP, Gee M. Dietary approaches, practical application. In: Foster GD, Nonas CA eds. Managing Obesity: A Clinical Guide. Chicago, IL ADA; 2004:98- 117.

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  1. January 9, 2017 at 8:15 pm — Reply

    The modern LCHF diet (low carb, high fat) is the most popular, effective, safe, healthy and recommended eating style by modern, enlightened MD’s, Nutritionist’s and other health care professionals who follow a functional medicine science (cure the core problem, don’t just remove symptoms) Even the government of Sweden has made the low carb, high GOOD fat, moderate protein diet the officially recommended diet for their citizens to lose weight and drastically improve their health!

    NASM is also using the wrong diet to compare with their conventional, high carb SAD diet (Standard American Diet) It’s not low carb, high protein, it’s LCHF, low carb, HIGH fat that most successful, modern athletes and sports organizations follow (like the LA Lakers, LeBron James, Kobe Bryant, etc) Even CBS Sports and Sports Illustrated wrote articles about how many top athletes now follow a modern, low carb, high fat diet and end up dominating their sport!

    The authors here are using very old and scientifically flawed information to promote a high carb diet that has caused most Americans to be fat and sick for the last 60 years! I can’t understand why NASM continues to push this old, obsolete high carb diet on people when most top scientists and medical doctors world wide (and even the country of Sweden!) have proven it to be the WORST way you can eat if you want to be healthy and/or lose body fat. Come on guys! Haven’t you heard of Paleo? Crossfit? Hugely popular ideas that millions of people follow, with super healthy results day in and day out.

    Consuming 45% to 65% of your daily calories from carbohydrates is a disaster that creates chronically high blood glucose levels and high insulin levels which force humans to not burn fat (both the fat you eat and your own body fat) and to actually store MORE fat on your body, even though you already have too much body fat!

    The only people who won’t be affected by this high carb diet NASM promotes, are those who are extremely active most days of the week and can burn off those extra, unneeded carbs. But for 90% of people who just exercise moderately or not at all, the NASM high carb diet will add more fat to your body and increase your risk of most chronic diseases caused by high insulin/high blood sugar from a 45% to 65% carbohydrate diet.

    Just go to to see a more unbiased, modern, and results proven review of the LCHF diet. Or watch the movies: “Cereal Killers”, “Cereal Killers 2: Run on Fat”

    Top medical doctors and scientists now mostly agree the LCHF is the healthiest diet for humans, like:
    Dr. Lustig from UCSF with his book: “Fat Chance”, Dr. Volek, & Dr. Phinney with their book: “The Art and Science of Low Carb”, Dr. Jason Fung, with his book: “The Obesity Code” , Mark Sisson, with the book: “The Primal Blueprint”, and the most popular, top selling diet books that are providing daily, healthy fat loss results for millions of people right now: “It Starts With Food”, “The Primal Blueprint”, “The Paleo Solution”, “The Paleo Diet”, and Dr. Mark Hyman’s book: “The Blood Sugar Solution”.

    The authors here are using very outdated information and cherry picked studies that come mostly from experts either supported by or friendly to sugar/carb friendly commodity food corporations who make a ton of money selling wheat, corn, and soy based food. Also, it’s not a low carb, high protein, it’s a low carb, high FAT, moderate protein diet that’s the most effective and safe by far.

    Randomized controlled trials showing significantly more weight loss with low carb diets
    Brehm BJ, et al. A Randomized Trial Comparing a Very Low Carbohydrate Diet and a Calorie-Restricted Low Fat Diet on Body Weight and Cardiovascular Risk Factors in Healthy Women. J Clin Endocrinol Metab 2003;88:1617–1623.
    Samaha FF, et al. A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity. N Engl J Med 2003;348:2074–81.
    Sondike SB, et al. Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factor in overweight adolescents. J Pediatr. 2003 Mar;142(3):253–8.
    Aude YW, et al. The National Cholesterol Education Program Diet vs a Diet Lower in Carbohydrates and Higher in Protein and Monounsaturated Fat. A Randomized Trial. Arch Intern Med. 2004;164:2141–2146.
    Volek JS, et al. Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women. Nutrition & Metabolism 2004, 1:13.
    Yancy WS Jr, et al. A Low-Carbohydrate, Ketogenic Diet versus a Low-Fat Diet To Treat Obesity and Hyperlipidemia. A Randomized, Controlled Trial. Ann Intern Med. 2004;140:769–777.
    Nichols-Richardsson SM, et al. Perceived Hunger Is Lower and Weight Loss Is Greater in Overweight Premenopausal Women Consuming a Low-Carbohydrate/High- Protein vs High-Carbohydrate/Low-Fat Diet. J Am Diet Assoc. 2005;105:1433–1437.
    Gardner CD, et al. Comparison of the Atkins, Zone, Ornish, and learn Diets for Change in Weight and Related Risk Factors Among Overweight Premenopausal Women. The a to z Weight Loss Study: A Randomized Trial. JAMA. 2007;297:969–977.
    Shai I, et al. Weight loss with a low-carbohydrate, mediterranean, or low-fat diet. N Engl J Med 2008;359(3);229–41.
    Krebs NF, et al. Efficacy and Safety of a High Protein, Low Carbohydrate Diet for Weight Loss in Severely Obese Adolescents. J Pediatr 2010;157:252-8.
    Summer SS, et al. Adiponectin Changes in Relation to the Macronutrient Composition of a Weight-Loss Diet. Obesity (Silver Spring). 2011 Mar 31. [Epub ahead of print]
    Daly ME, et al. Short-term effects of severe dietary carbohydrate-restriction advice in Type 2 diabetes–a randomized controlled trial. Diabet Med. 2006 Jan;23(1):15–20.
    Westman EC, et al. The effect of a low-carbohydrate, ketogenic diet versus a low- glycemic index diet on glycemic control in type 2 diabetes mellitus. Nutr. Metab (Lond.)2008 Dec 19;5:36.

  2. Nicole
    January 11, 2017 at 10:56 pm — Reply

    Your statement, “In most formats, the carbohydrate-modified
    (low-carbohydrate/high-protein) diet is a ketogenic diet, which induces a
    state of ketosis through severe limitation of dietary carbohydrates” is not exactly correct. A HIGH protein, low carb diet is not ketogenic. A ketogenic diet is low carb, MODERATE protein, and (most importantly) high fat. Fat is 70-75% of the diet, protein 15-20%, and carbs 5-10% of the diet. I do agree with you completely though that not all diets/way of eating works for everyone. While I love carbs and could eat a loaf of bread in a day, the inflammation that came from eating carbs and sugar just wasn’t worth it. Immense shin pain that only went away after switching to ketogenic… plus, lowered cholesterol, triglycerides (298 to 111), and of course, weight loss. I eat upwards of 1600 calories and my workouts have not suffered at all but gotten better. So, people should also not only consider what they like and want in their diet but decide if it’s worth it. Yes, I want sweet potato’s but just a little carb cheat brings the shin pain back and that’s just not worth it for me.

    • Struth
      March 10, 2017 at 7:16 pm — Reply

      I agree, I feel much stronger and my endurance is so much better on my keto diet. I don’t get the horrible fatigue and lactic acid burnout that I used to when running or lifting. I feel much stronger and my endurance is so much better on my keto diet. For health reasons, I switched to the keto way of eating this last year. Atkins (in my 30’s) and the keto diet (currently) are the ONLY way I have managed to stay healthy (not thin). My blood/test numbers support my choice of living. As stated previously, keto is moderate protein; I eat MODERATE amounts of protein; still within the .8 per pound required due to my age (over 50) and my 5-6 day workouts. I eat the best fats like coconut, avocado, olive oil as well as flax and chia seeds and nuts. As far as the American Heart Association – they lost credibility with me in the 90’s when I followed their diet and ate grapes and pretzels as part of my low fat diet. My skin looked like crap, and I was about 45 pounds overweight; yet exercising myself to death. No thanks. I find personal experience, common sense, and keeping up on the latest scientific information works best for me. BTW, most of the references cited above are from 2005. I think we’ve come a long way in our science and findings in 12 years. Time to update!

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