Placing limits on total fat intake has no basis in science

In a Viewpoint published today in the Journal of the Medical Association (JAMA), researchers from the Friedman School of Nutrition Science and Policy at Tufts University and Boston Children's Hospital call on the federal government to drop restrictions on total fat consumption in the forthcoming 2015 Dietary Guidelines for Americans.

Co-authors Dariush Mozaffarian, M.D., Dr.P.H., dean of the Friedman School, and David Ludwig, M.D., Ph.D., director of the New Balance Foundation Obesity Prevention Center at Boston Children's Hospital, highlight a key, but overlooked, focus of the 2015 Dietary Guidelines for Americans Committee (DGAC), a group of independent scientists convened by the federal government to review current scientific and medical literature on nutrition. For the first time since 1980, the DGAC did not propose restricting total fat consumption in its technical report, released in February. According to the current dietary guidelines, only up to 35 percent of daily calories should come from fat.

By the end of this year, the U.S. Department of Agriculture (USDA) and the U.S. Department of Health and Human Services (HHS) will write the final Dietary Guidelines for Americans, referring to the DGAC report for guidance. The 2015 Dietary Guidelines for Americans are scheduled to be published later this year.

'Placing limits on total fat intake has no basis in science and leads to all sorts of wrong industry and consumer decisions,' Mozaffarian said. 'Modern evidence clearly shows that eating more foods rich in healthful fats like nuts, vegetable oils, and fish have protective effects, particularly for cardiovascular disease. Other fat-rich foods, like whole milk and cheese, appear pretty neutral; while many low-fat foods, like low-fat deli meats, fat-free salad dressing, and baked potato chips, are no better and often even worse than full-fat alternatives. It's the food that matters, not its fat content.'

For obesity prevention, the DGAC recommends shifting the focus from total fat intake to adoption of a healthier food-based dietary pattern with more vegetables, fruits, whole grains, nuts, seafood and beans; and fewer meats, sugars, and refined grains.

'When U.S. guidelines began recommending low-fat diets in 1980, people responded by turning to low-fat or non-fat products, away from healthy high-fat foods and toward refined grains and added sugars,' Ludwig said. 'A growing body of research shows that refined carbohydrates increase metabolic dysfunction and obesity. Yet, foods rich in added sugars, starches and refined grains like white bread, white rice, chips, crackers and bakery desserts still account for most of the calories people eat. Lifting the restriction on total fat would clear the way for restaurants and industry to reformulate products containing more healthful fats and fewer refined grains and added sugars.'

To maximize success, Mozaffarian and Ludwig call on a wide range of other government agencies and programs to also lift the limit on total fat. This includes the National School Lunch program, which recently banned whole milk while keeping sugar-sweetened non-fat milk on cafeteria menus; the FDA, which regulates health claims and food package labeling and remains strongly low-fat focused; and the National Institutes of Health, whose guidelines on healthy diets for families and children classify fat-free creamy salad dressing and trimmed beef and pork as foods to 'eat almost any time' while being cautious about eating vegetables cooked with added fat, nuts, vegetable oil and olive oil.

'From agriculture to food producers to school cafeterias to restaurants, the Dietary Guidelines for Americans serve as a beacon for countless dietary choices in the public and private sector,' Mozaffarian said. 'With obesity and chronic disease impacting public health so deeply, we can't miss this critical opportunity to improve the food supply. The USDA and HHS must use the 2015 guidelines to send the message that limiting total fat provides no benefits and actually leads to confusion and bad dietary choices.'