The Annals of Internal Medicine just published results of a National Institutes of Health (NIH) trial titled "Effects of low-carbohydrate and low-fat diets," in which a low-carbohydrate diet was found to be more effective both for weight loss and cardiovascular risk factor reduction than a low-fat diet.
Participants in this study were assigned to one of two groups: low carbohydrate and low fat. In the low carbohydrate group, participants were instructed to count "net carbs" of less than 40 grams/day, similar to the Atkins Diet™. Researchers refer to this as digestible carbohydrate -- total carbohydrate minus total fiber.
As with the Atkins approach, participants were not given a strict calorie limit, nor were they told they needed to pair with an exercise regimen to see results. Following these guidelines, the low-carbohydrate group saw greater improvements in measures of body composition, good cholesterol, cholesterol ratio, triglycerides and overall reduction in cardiovascular risk.
Researchers utilized a gold-standard risk assessment tool known as the 10-year CHD Framingham Risk Score. This analysis, developed by the NIH National Heart, Lung and Blood Institute, predicts a person's chance of having a heart attack in the next 10 years and is based on factors including age, gender, cholesterol values, blood pressure and smoking status. Using this tool, the research trial results showed significant decreases in an estimated ten-year risk for coronary heart disease at six and twelve months. Additionally, reductions were significantly greater in the low-carbohydrate group at twelve months.
"Over the past fifteen years, over 20 randomized clinical trials compared low carbohydrate to the standard recommendation, a low fat diet. And consistently these trials show that carbohydrate restriction is the best approach for weight management," states Jonathan Sackner-Bernstein, MD, board-certified cardiologist and former senior FDA official. "The data from Bazzano and colleagues confirm that the low carbohydrate strategy yields significantly better weight loss than the standard recommendation of a low fat diet. This study extends prior observations by calculating the risk of a major cardiovascular event such as a heart attack. By using the Framingham Risk Calculator, they show that the low carbohydrate strategy significantly lowers the risk of cardiovascular events."
"I commend the researchers with Tulane University School of Public Health and Tropical Medicine for helping reduce confusion on this subject by crystalizing the message that dietary fat does not make people fat, and it also does not negatively impact heart health," states Colette Heimowitz, VP of Nutrition Education for Atkins. "Though it should be noted that this study is not the first to do so, it simply adds to the bank of research over the past decade that continues to confirm that lower carb, higher fat eating can successfully lead both to weight loss and improvements in cardiometabolic measures."
Additionally, authors make a call out to National Dietary Guidelines authorities, implying that dietary fat, and specifically saturated fat, has been unduly associated with heart disease outcomes, including metabolic syndrome. Metabolic syndrome is a group of risk factors including high blood pressure, high blood sugars, excess body fat and cholesterol levels that are notable precursors of diabetes heart disease and stroke. "This study adds to the body of evidence that low fat diets are not healthier diets. We need to re - evaluate dietary guidelines that limit fat including saturated fat," reports carbohydrate expert, Professor Joanne Slavin, PhD, RD from the Department of Food Science and Nutrition at the University of Minnesota.