It is New Year's resolution time and one of the perennial resolutions for many Americans is, "this year I am going to lose weight and keep it off."
Literally two thirds of Americans are overweight or worse, so there are a lot of such resolutions being made. Like gym memberships, however, there are far more resolutions initially undertaken than followed through. Nevertheless, this time around things can be different. One key is that the weight loss strategy adopted should also be one that can be continued as a normal everyday diet pattern. There is no reason that this should not work as long as realistic goals are adopted. Life, as the observation goes, is a marathon, not a sprint. Moderate, yet well thought-out changes in the diet regarding the ratios of protein, carbohydrate and fat can yield durable results over a span of three to six months. Similarly, care in terms of the timing of food intake, consumption of fiber and phytonutrients, and so can yield big rewards.
High Protein Beats High Carbohydrate During Weight Loss
Let's start with the initial weight loss goal. Ads for diet products and programs often promise "ten pounds in ten days," but such promises, even were they true, are never lasting. The body resists extreme changes and, in the end, the body always wins. A better approach is to coax the body in the desired direction so that it becomes more metabolically flexible and thus can burn fat for energy rather than storing it. This means overcoming roadblocks such as poor blood sugar control dieting-induced loss of lean tissue. The protein-to-carbohydrate make-up of meals is important here. Indeed, this ratio and not the amount of fat in the diet is determining.
Realistically, reducing energy intake by approximately 500 calories per day is sufficient for many dieters initially to experience weight loss of 1 – 2 pounds per week. The catch is that weight loss based only on restricting calories has a poor record for improving impaired glucose tolerance and typically leads to a loss of the more actively calorie-metabolizing lean body tissues. A study with obese subjects published in the journal BMJ Open Diabetes Res Care demonstrates that this need not be the outcome of dieting.1 One hundred percent of obese adults using a high protein (HP) moderately calorically-restricted diet, but not those on a similarly restricted high carbohydrate (HC) diet achieved a return to normal glucose tolerance in addition to benefits in their markers for cardiovascular and inflammatory health. On the HP diet there was an increase in the percentage of lean body mass and a decrease in the percentage of fat body mass with weight loss whereas the HC diet led to a decrease in the percentage of lean body mass along with a decrease in the percentage of fat body mass. The change in glucose tolerance/blood sugar levels and the improvement in the percent lean body mass demonstrated with higher protein intake and restricted carbohydrate intake are highly desirable outcomes. The key was substituting protein for carbohydrate calories.
For this study, researchers randomized 24 women and men with elevated fasting glucose levels in the pre-diabetic range to either a HP diet (30 percent protein, 30 percent fat, 40 percent carbohydrate; n=12) or a HC diet (15 percent protein, 30 percent fat, 55 percent carbohydrate; n=12) for a study lasting six months. All meals were provided to these subjects for the six months. At the start of the study and at its conclusion, tests were performed to determine oral glucose tolerance and serum insulin levels as well as a variety of other parameters indicative of metabolism and inflammation. X-ray scans were conducted to determine body composition in terms of the percentage of lean and fat tissue.
The differing diets led to dramatically different results. According to the authors of the paper, on the HP diet 100 percent of the subjects exhibited remission of their pre-diabetes to normal glucose tolerance whereas only 33.3 percent of subjects on the HC diet exhibited this remission. Moreover, the high protein arm subjects exhibited significant improvement in (1) insulin sensitivity (p=0.001), (2) cardiovascular risk factors (p=0.04), (3) inflammatory cytokines (p=0.001), (4) oxidative stress (p=0.001), and (5) increased percent lean body mass (p=0.001) compared with the HC diet.
In terms of the findings likely to be of particular interest to most dieters, it should be pointed out again there was an increase in the percentage of lean body mass and decrease in the percentage of fat body mass with weight loss on the HP diet. In contrast, there was a decrease in the percentage of lean body mass with weight loss on the HC diet although the percentage of fat body mass did decline as expected. Importantly, both metabolic parameters and inflammation markers were improved only on the high protein / reduced carbohydrate, moderately calorically restricted diet.
Doesn't Eating Fat Make You Fat?
Keeping weight off after a diet is the real challenge. The fact that in dieting it is mostly the caloric restriction that leads to weight loss and not diet specifics has been known for decades.2 For instance, in 1996 a study was published that compared diets much more disparate than the one described above.3 Forty-three obese adults were randomly assigned to receive diets containing 1,000 calories/day composed of either 32 percent protein, 15 percent carbohydrate, and 53 percent fat or 29 percent protein, 45 percent carbohydrate, and 26 percent fat. There was no significant difference in the amount of weight lost. Nevertheless, just as in the study above, fasting plasma glucose, insulin, cholesterol, and triacylglycerol concentrations decreased significantly in patients eating low-energy diets that contained 15 percent carbohydrate, but neither plasma insulin nor triacylglycerol concentrations fell significantly in response to the higher carbohydrate diet.
A more recent study looked at moderate energy intake on a very high-fat, low-carbohydrate (73 percent of energy from fat, 10 percent of energy from carbohydrate and 17 percent of energy from protein) or low-fat, high-carbohydrate (30 percent of energy from fat, 53 percent of energy from carbohydrate and 17 percent of energy from protein) diet for 12 weeks.4 Unlike most modern diets, these were diets involving only minimally processed carbohydrates and fats. Despite expectations, the high fat diet did not raise LDL cholesterol; however, it did raise HDL cholesterol. According to one of the co-authors of the study, "the very high intake of total and saturated fat did not increase the calculated risk of cardiovascular diseases." "Participants on the very-high-fat diet also had substantial improvements in several important cardiometabolic risk factors, such as ectopic fat storage, blood pressure, blood lipids (triglycerides), insulin and blood sugar."5
Therapeutic diets usually restrict either carbohydrates or fats. If fats are restricted, then the diet will tend towards an increased protein content. Most dieters will find that in the early stages, this high intake of protein will reactivate the thyroid and make life easier. There is plenty of clinical evidence to the effect that high protein snacks reduce calorie intake more than do snacks of carbohydrate, fat or alcohol for overweight individuals accustomed to the usual American mixed diet. And increasing protein intake to 25 percent of calories clinically has been demonstrated to increase both weight loss (by 75 percent) and fat loss (by 57 percent) more than was found on a protein intake of 12 percent. Still, eating protein is not a panacea (too much is too much6) and protein needs to be matched with goodly intakes of fruit and vegetables as well as the avoidance of refined carbohydrates for best results. Moreover, decades of research, as indicated above, demonstrates that carbohydrates need to be replaced by protein for best results.
Does Gut Bacteria Play a Role in Weight Regain?
Preserving lean tissue and improving various metabolic parameters certainly help to make dieting results more stable and lasting. An additional factor, one seldom considered, is the role of gastrointestinal bacteria in weight maintenance. Human experiments have demonstrated that changing the diet to artificially induce blood sugar regulation issues surprisingly quickly results in changes in the gut microbiome that cause these bacteria to release more calories from food than normally would be the case, for instance, by digesting supposedly indigestible fiber. Similarly, it is well established that individuals who are overweight, obese and/or diabetic often have substantially different gut microflora than individuals who are lean.7 Therefore, so-called yo-yo dieting and recurrent obesity might be at least influenced by the microbes found in the gut.
A recent report in Nature casts further light on an aspect of this issue.8 As observed by one of the authors, Dr. Eran Elinav from the Weizmann Institute of Science in Israel, "we've shown in obese mice that following successful dieting and weight loss, the microbiome retains a 'memory' of previous obesity." Co-author Professor Eran Segal elaborated, "this persistent microbiome accelerated the regaining of weight when the mice were put back on a high-calorie diet or ate regular food in excessive amounts." One of the findings of this research is that the post-diet gut biome destroys certain flavonoids from the diet that influence energy metabolism. This interferes with energy release from fat. In post-dieting mice this leads to an accumulation of extra fat when they are returned to a higher-calorie diet. Experimentally, according to the paper, "flavonoid-based 'post-biotic' intervention ameliorates excessive secondary weight gain." This suggests that microbiome-targeting approaches may help with weight regain.
Putting It TogetherReferences
Diets similar to the 30 percent protein, 30 percent fat, 40 percent carbohydrate diet described above have been proposed for several decades.9 In addition, the role of phytonutrients now is strongly supported. Both these aspects of good meal planning need to be addressed. A simple approach to meals is to make sure that roughly one third of the plate is covered with a protein source and one half or even two thirds of the meal plate is covered with the lightly cooked vegetable of your choice (salad does not count here; corn and carrots are counted as carbohydrates). Always eat this vegetable serving, which should be at least two cups of vegetables. Eat protein before eating any carbohydrates in the main meal for better digestion and better appetite control. (Classic European, Chinese and Japanese meal planning often arranges protein courses before carbohydrate courses.) Remember that vegetables are perfectly good carbohydrate sources and may well be consumed in the place of concentrated carbohydrates, such as rice and potatoes. Dieters also should consider supplementing with probiotics in conjunction with prebiotics. Finally, as noted in previous TotalHealth articles, when meals are eaten may be as important and what is eaten; never skip breakfast and avoid eating late in the evening or before bedtime.10
- 1. Stentz FB, Brewer A, Wan J, Garber C, Daniels B, Sands C, Kitabchi AE. Remission of pre-diabetes to normal glucose tolerance in obese adults with high protein versus high carbohydrate diet: randomized control trial. BMJ Open Diabetes Res Care. 2016 Oct 26;4(1):e000258.
- 2. Sacks FM, Bray GA, Carey VJ, Smith SR, Ryan DH, Anton SD, McManus K, Champagne CM, Bishop LM, Laranjo N, Leboff MS, Rood JC, de Jonge L, Greenway FL, Loria CM, Obarzanek E, Williamson DA. Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. N Engl J Med. 2009 Feb 26;360(9):859–73.
- 3. Golay A, Allaz AF, Morel Y, de Tonnac N, Tankova S, Reaven G. Similar weight loss with low- or high-carbohydrate diets. Am J Clin Nutr. 1996 Feb;63(2):174–8.
- 4. Veum VL, Laupsa-Borge J, Eng Ø, Rostrup E, Larsen TH, Nordrehaug JE, Nygård OK, Sagen JV, Gudbrandsen OA, Dankel SN, Mellgren G. Visceral adiposity and metabolic syndrome after very high-fat and low-fat isocaloric diets: a randomized controlled trial. Am J Clin Nutr. 2016 Nov 30. pii: ajcn123463. [Epub ahead of print]
- 5. University of Bergen. "Saturated fat could be good for you, study suggests." ScienceDaily. ScienceDaily, 2 January 2017. www.sciencedaily.com/releases/2016/12/161202094340.htm.
- 6. Rietman A, Schwarz J, Tomé D, Kok FJ, Mensink M. High dietary protein intake, reducing or eliciting insulin resistance? Eur J Clin Nutr. 2014 Sep;68(9):973–9.
- 7. Zhang Q, Wu Y, Fei X. Effect of probiotics on body weight and body-mass index: a systematic review and meta-analysis of randomized, controlled trials. Int J Food Sci Nutr. 2015 Aug;67(5):571–80.
- 8. Thaiss CA, Itav S, Rothschild D, Meijer M, Levy M, Moresi C, Dohnalová L, Braverman S, Rozin S, Malitsky S, Dori-Bachash, M. Kuperman Y, Biton I, Gertler A, Harmelin A, Shapiro H, Halpern Z, Aharoni A, Segal E, Elinav E. Persistent microbiome alterations modulate the rate of post-dieting weight regain. Nature. 2016 Nov 24. doi:10.1038/nature20796.
- 9. Sears B, Ricordi C. Anti-inflammatory nutrition as a pharmacological approach to treat obesity. J Obes. 2011;2011.
- 10. Sellix MT. For Management of Obesity and Diabetes: Is Timing the Answer? Endocrinology. 2016 Dec;157(12):4545–9.
The Protein/Carbohydrate/Fat Diet Face-Off!
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Dallas Clouatre, PhD
Dallas Clouatre, Ph.D. earned his A.B. from Stanford and his Ph.D. from the University of California at Berkeley. A Fellow of the American College of Nutrition, he is a prominent industry consultant in the US, Europe, and Asia, and is a sought-after speaker and spokesperson. He is the author of numerous books. Recent publications include "Tocotrienols in Vitamin E: Hype or Science?" and "Vitamin E – Natural vs. Synthetic" in Tocotrienols: Vitamin E Beyond Tocopherols (2008), "Grape Seed Extract" in the Encyclopedia Of Dietary Supplements (2005), "Kava Kava: Examining New Reports of Toxicity" in Toxicology Letters (2004) and Anti-Fat Nutrients (4th edition).