Because different types of fat have different health effects, the 2015 dietary Guidelines Advisory Committee (DGAC) report
suggests that dietary advice should put the emphasis on optimizing types of dietary fat and not reducing total fat. In keeping with the conclusions of the 2015 DGAC report, the 2015-2020 U.S. Dietary Guidelines eliminated the advice to limit total dietary cholesterol and to limit total dietary fat that were prominent features of previous reports.
So perhaps the well-intentioned advice to eat low-fat may have backfired and harmed rather than improved health because we substituted sugar and refined carbohydrates for the fat eliminated from our diets. At least over the past few decades, sugar, highly refined carbohydrates, and calorie intake has increased substantially, the prevalence of obesity tripled, and the incidence of type 2 diabetes increased many-fold. Other lifestyle factors such as less physical activity, more eating out, and the consumption of ever-larger food portions probably also influenced these trends. Still, there is evidence that the added sugars and refined grains of processed foods are major contributors to the metabolic dysfunction, obesity, diabetes, and cardiovascular disease epidemics that characterize health in America.
So, is the advice to limit total fat in the diet wrong and obsolete? One problem with almost all of the studies cited that show lack of benefit from low-fat eating is that they define low-fat as up to 30% of total calories from fat. The clinicians who have seen remarkable improvements in both cardiovascular health and biomarkers such as LDL-C with very low-fat diets would argue that a diet with 30% of energy from fat is not low enough in fat to bring about substantial improvement in health. I use the term ultra-low-fat (ULF) diets to describe diets with 10%, or at most 15%, of daily calories supplied by fat.
The view of ULF advocates is that a reduction in fat to 10% to 15% of total calories, and importantly, replacement of the missing fat calories with unprocessed or minimally processed plant-based foods, is required to obtain the favorable health changes they have seen but ultra-low-fat diets are unlikely to be healthy if they substitute refined carbohydrates for fat. Mozaffarian et al. have observed that a very low-fat, high-carbohydrate diet does have the potential to be cardio-protective as long as most of the carbohydrates are minimally processed. Future blogs on diet will describe the benefits of the ULF eating plans of Pritikin, Ornish, Esselstyn, and others.
In summary, a prominent problem with reducing fat calories in the American diet is that it that the calories have been replaced with unhealthy refined grains and added sugars. But the response to this situation should not be to go back to a high saturated fat burgers and butter diet, rather to focus on plant-based eating that includes healthy (mono and polyunsaturated) fats and the carbohydrates found in whole foods, such as beans, legumes, fruit and vegetables.
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). Copyright 2021 by J. Joseph Speidel.