Some nutrition experts say only the type of fat matters to health, but others recommend very low-fat diets. According to some popular media, the longstanding concern about large amounts of fat in the diet as a detriment to health is an obsolete
concept, an unfortunate error that has harmed public health. For example, Nina Teicholz the author of the book The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet, blamed epidemiologic studies that showed an association between high-fat diets and CVD, (and not irrefutable causation), for subjecting Americans to a “…vast, uncontrolled diet experiment with disastrous consequences.”
A New York Times op-ed by Mozaffarian and Ludwig made a reasonable suggestion to “Stop Fearing Fat” and advanced a proposition for which there is much relevant evidence, that is that the type of fats consumed influences cardiometabolic
health more than the proportion of calories consumed from total fat.
The primary rationale for limiting total fat to 30% in the 1980 U.S. Dietary Guidelines and a range from 20% to 35% of total calories in the 2005 Guidelines, was to lower saturated fat and dietary cholesterol, which were associated with increased cardiovascular risk. But as Mozaffarian and Ludwig pointed out in a 2015 editorial in the Journal of the American Medical Association (JAMA), “…. the campaign against saturated fat quickly generalized to include all dietary fat.”
With regard to total fat in the diet, the 2015 DGAC reported that diets with a lower percentage of energy from fat did not improve lipid profiles or reduce the risk of heart disease, diabetes, cancer, or adiposity (overweight or obesity). The Food and Agriculture Organization also noted that several randomized control trials had not found evidence for the beneficial effects of low-fat diets. For example, a low-fat (27% to 30% of energy from fat), high-carbohydrate diet did not favorably affect serum lipids, fasting serum glucose, fasting serum insulin, or blood pressure, compared with higher fat diets.
The longstanding advice to eat low-fat foods, and the marketing of a spate of highly processed low-fat foods, undoubtedly has played a part in the decline in consumption of dietary fat in the U.S. from about 40% of calories to near the often-recommended limit of 30% total energy. But there were unintended consequences. As fat has been lowered in the American diet, it has almost always been replaced with processed foods that have large amounts of added sugar and other refined carbohydrates.
This is a prominent reason for the current criticism of low-fat diets. Studies suggest that substitution of saturated fat with highly processed carbohydrates (e.g. added sugar and refined grains) does not lower cardiovascular risk, whereas substitution of saturated fat with unprocessed plant-based foods or the “healthful” unsaturated fats found in nuts, vegetable oils, and fish reduces the risk of cardiovascular disease.
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.