New year, new diet = New you?

With the new year comes a potential for a new you, but with every Google search your confusion is mounting on what diets to follow and how to lose those extra pounds. Many websites and books are advocating for low carbohydrate diets as the sweeping cure-all solution to obesity, but is this diet a fad or the real deal?

The upcoming release of the 2015 Dietary Guidelines for Americans (DGA) is anticipated by those with an interest in nutrition. But not everyone agrees with the results from the committee of U.S. nutrition experts and their interpretation of the body of evidence in nutrition science that often has studies and opinions that are conflicting. Some are now coming forward and charging that the DGA recommendations for low amounts of dietary fats and increased carbohydrates are responsible for the U.S. obesity epidemic. However, the facts tell a different story.

First, national studies of food consumption show that only 3-8% of Americans actually follow the DGA. Second, if most people were eating more fruits, vegetables, and whole grains, lean proteins, and low or non-fat dairy servings, and consuming fewer solid fats and added sugars, and less sodium as suggested by the DGA, Americans would be healthier and obesity would be less of a problem.

Although the DGA have urged Americans to cut back on solid fats for many years, we simply have not followed that advice. Data from the National Health and Nutrition Examination Survey (NHANES) reveal that fat intake among U.S. adults has remained constant at about 80-90 grams per day since 1971. The truth is that Americans have never gone low-fat. How can an obesity epidemic be blamed on something that never happened?

Many approaches to solving the obesity crisis have been tried. Millions of consumers have already tried a never ending stream of diets, including the low-carb diets that first became popular in the 1960s. But, if they really worked, why wouldn’t Americans have just stayed on them? Like all “diets,” low-carb fails in the long term to keep weight off. Clearly, if low-carb diets were the answer to obesity, we would not have an obesity crisis. The bottom line: it’s the calories, not the carbs.

Every five years, the Dietary Guidelines Advisory Committee reviews the latest science on nutrition and health and makes recommendations that reflect this review and best serve the needs of the United States population. Some are now claiming that the Dietary Guidelines Advisory Committee has ignored the latest findings on saturated fat and its role in heart disease. In fact, it hasn’t. The Committee has recommended, based on a preponderance of evidence about which there is no disagreement in the scientific arena, that Americans adopt dietary patterns similar to the Mediterranean and DASH diets, both of which emphasize fruits, vegetables, whole grains, low-fat dairy, lean protein sources, and mono and unsaturated fats. 

This is not new advice; while the messages may be worded differently, the advice on what to eat hasn’t changed substantially over the 35 years (see table) that the Committee has been making recommendations. 

The problem is not with the Dietary Guidelines.  The problem is, and has been, that so few Americans seem to follow them.

Dr. Glenn Gaesser, Professor of Exercise Science and Health Promotion
School of Nutrition & HealthDirector of the Healthy Lifestyles Research Center
Arizona State University, Phoenix, AZ

Dr. Julie M. Jones, PhD, CNS, LN
Distinguished Scholar and Professor Emerita of Nutrition
Department of Exercise & Nutritional Sciences 
St. Catherine University, St. Paul, MN