High-fat, high-protein, low-carb diets may have risks associated with their long-term use. Editorial comment on a
meta-analysis study of 48 weight loss trials noted that “Protein intakes of 30% of kilocalories,
or double what the other diets provide, raise questions about possible long-term
influences on kidney function, calcium losses, and other questions that should
be explored.”

The Preventing Overweight Using Novel Dietary Strategies (POUNDS LOST) trial
compared weight loss from diets made up of healthier food with differing proportions
of macronutrients. The trial tested four diets with a 750 calorie per day deficit
from estimated requirements: (1) a low-fat, average protein diet (20% fat, 15% protein,
and 65% carbohydrate), (2) a low-fat, high protein diet (20% fat, 25% protein,
and 55% carbohydrate), (3) a high-fat, average protein diet (40% fat, 15% protein,
and 45% carbohydrate), and (4) a high-fat, high protein diet (40% fat, 25% protein,
and 35% carbohydrate). The study found that at two years, weight losses were similar
across all four diets and that body fat, abdominal fat, and hepatic fat were also
similar, and there were no differences in loss of lean body mass.

A commentary on the study noted that “…regardless of their macronutrient composition, weight loss
was associated with significant reductions in cravings for fats, sweets, and starches
while cravings for fruits and vegetables increased” and that, “… over time people
not only adapted but actually preferred the taste of the nutrient-dense foods, such
as fruits and vegetables, reflecting enhanced adherence to recommended intake of

The finding that either low-fat or low-carb eating can have comparable effects on
weight was also found in a 2018 Stanford study published in the JAMA. It compared
the effect of counseling and a healthy low-fat diet (29% fat) to a healthy
low-carbohydrate diet (45% fat) on weight change. The study found that a weight
loss averaging 12 to 13 pounds over 12 months was not significantly different for
each of the diets. It was also found that neither genotype pattern nor baseline insulin
secretion was associated with the dietary effects on weight loss. All study
subjects were encouraged to select a healthy diet featuring vegetables, minimally
processed foods, and to eliminate or minimize added sugars and refined grain products.

The low carb group, who consumed more saturated fats, had an increase in
unhealthy LDL-cholesterol, whereas the LDL-cholesterol declined in the low-fat
group. Triglycerides declined in both groups but more in the low carb group.

A similar study, published in Circulation, compared a lacto-ovo vegetarian (no fish
or meat) diet and a Mediterranean Diet that included fish, dairy, poultry, and some
red meat. The two diets were equally effective in reducing body weight, BMI,
and fat mass. The vegetarian diet was more effective in reducing LDL-cholesterol
levels, while the Mediterranean Diet, as in the Stanford study, significantly reduced
triglyceride levels.

This blog presents opinions and ideas and is intended to provide helpful general information. I am not engaged in rendering advice or services to the individual reader. The ideas, procedures and suggestions in that are presented are not in any way a substitute for the advice and care of the reader’s own physician or other medical professional based on the reader’s own individual conditions, symptoms or concerns. If the reader needs personal medical, health, dietary, exercise or other assistance or advice the reader should consult a physician and/or other qualified health professionals. The author specifically disclaims all responsibility for any injury, damage or loss that the reader may incur as a direct or indirect consequence of following any directions or suggestions given in this blog or participating in any programs described in this blog or in the book, The Building Blocks of Health––How to Optimize Your Health with a Lifestyle Checklist (available in print or downloaded at Amazon, Apple, Barnes and Noble and elsewhere). Copyright 2021 by J. Joseph Speidel,