In the introduction to “Postprandial Thermogenesis Is Increased 100% on a High-Protein, Low-Fat Diet versus a High-Carbohydrate, Low-Fat Diet in Healthy, Young Women” (Journal of the American College of Nutrition, Vol. 21, No. 1, 55-61 (2002)), Carol S. Johnston, PhD, FACN, Carol S. Day, MS and Pamela D. Swan, PhD write:
Counter to the current U.S. Dietary Guidelines which promote diets high in complex carbohydrates (58% of total daily energy) , recent clinical investigations support the efficacy of high-protein, reduced fat diets for weight loss, as well as for improved insulin sensitivity and blood lipid profiles.They should not be scared of fat!! It is grains and sugars that make us fat and unhealthy, not the fats we eat! They just cannot get over that prejudice. The abstract to their research says (the statistics here are beautiful…):
Objective: The recent literature suggests that high-protein, low-fat diets promote a greater degree of weight loss compared to high-carbohydrate, low-fat diets, but the mechanism of this enhanced weight loss is unclear. This study compared the acute, energy-cost of meal-induced thermogenesis on a high-protein, low-fat diet versus a high-carbohydrate, low-fat diet. Methods: Ten healthy, normal weight, non-smoking female volunteers aged 19-22 years were recruited from a campus population. Using a randomized, cross-over design, subjects consumed the high-protein and the high-carbohydrate diets for one day each, and testing was separated by a 28- or 56-day interval. Control diets were consumed for two days prior to each test day. On test day, the resting energy expenditure, the non-protein respiratory quotient and body temperature were measured following a 10-hour fast and at 2.5-hour post breakfast, lunch and dinner. Fasting blood samples were collected test day and the next morning, and complete 24-hour urine samples were collected the day of testing. Results: Postprandial thermogenesis at 2.5 hours post-meal averaged about twofold higher on the high protein diet versus the high carbohydrate diet, and differences were significant after the breakfast and the dinner meals (p < 0.05). Body temperature was slightly higher on the high protein diet (p = 0.08 after the dinner meal). Changes in the respiratory quotient post-meals did not differ by diet, and there was no difference in 24-hour glomerular filtration rates by diet. Nitrogen balance was significantly greater on the high-protein diet compared to the high-carbohydrate diet (7.6 ± 0.9 and -0.4 ± 0.5 gN/day, p < 0.05), and at 24-hour post-intervention, fasting plasma urea nitrogen concentrations were raised on the high protein diet versus the high-carbohydrate diet (13.9 ± 0.9 and 11.2 ± 1.0 mg/dL respectively, p < 0.05). Conclusions: These data indicate an added energy-cost associated with high-protein, low-fat diets and may help explain the efficacy of such diets for weight loss.