Clinical Edge

Summaries of Must-Read Clinical Literature, Guidelines, and FDA Actions

Carbs, fat, and mortality: Types matter more than levels

Key clinical point: The type of carbohydrates and fats in a diet matter more than whether or not a diet is low carb or low fat.

Major finding: For every 20-percentile increase in healthy low-carbohydrate diet score, mortality fell by an adjusted, relative 9%.

Study details: Analysis of diet and mortality data collected from 37,233 Americans during 1999-2014.

Disclosures: The study received no commercial fundings, and the authors had no commercial disclosures.


Shan Z et al. JAMA Intern Med. 2020 Jan 21; doi: 10.1001/jamainternmed.2019.6980.


This is an important study because the findings reinforce the already established concept that it’s the quality of the fat and carbohydrate a person eats that matters for health, rather than the relative levels of these nutrients. Eating unsaturated fats and unprocessed carbohydrates like whole grains, fruits, and legumes produces the greatest health and survival, while higher levels of saturated fats and processed carbs in the diet produce health problems. That’s much more important than whether a diet is low fat or low carb. This means sticking with the food principles advanced by the AHA diet, the DASH diet, and a Mediterranean diet.

Several prior studies have reported similar findings. For example, a recent report on more than 116,000 U.S. women and men with nearly 5 million person-years of follow-up showed a significant link between increased coronary heart disease events and high dietary levels of refined grains and added sugars, as well as decreased coronary events in people with high dietary levels of whole grains, nuts, legumes, fruits, and vegetables (J Am Coll Cardiol. 2017 Jul;70[4]:411-22). I cited additional data and went into further detail about the adverse coronary heart disease effects from diets with significant levels of refined starches and added sugars in an editorial (J Am Coll Cardiol. 2015 Oct 6;66[14]:1549-51).

High-fat and low-carb diets are popular because people who follow them lose weight over the short term, but those weight losses are hard to sustain longer term and create an opportunity for unhealthy effects if people eat the wrong fats, carbohydrates, and proteins. Strategies that focus on healthier food choices like the Mediterranean or AHA diets can minimize disease and produce more sustainable weight control.

Robert A. Vogel, MD , is a cardiologist in Denver affiliated with the University of Colorado School of Medicine and the VA Medical Center in Denver. He has been a consultant to the Pritikin Longevity Institute in Doral, Fla. He made these comments in an interview.