A new study, published in the New England Journal of Medicine, found that to lose weight you need to eat less, regardless of what you eat. The project study, Preventing Overweight Using Novel Dietary Strategies, a 2-year study on diet and weight loss, found that regardless of the relative proportion of the three major nutrients (protein, carbohydrate, and fat) similar weight losses were obtained after six months of dieting.
Four diet were tested in this study:
Low-fat: 20% fat, 15 % protein, 65 % carbohydrate
Low-fat, high protein: 20 % fat, 25 % protein, 55 % carbohydrate
High-fat, average protein: 40 % fat, 15 % protein, 45 % carbohydrate
High-fat, high-protein: 40 % fat, 25 % protein, 35 % carbohydrate
All diets had low saturated fat and cholesterol content and a high proportion of dietary fiber. Activity levels were set at 90 minutes for all participants who followed these nutritional guidelines for six months and were again evaluated after 2 years. More than 800 people (obese and/or overweight adults) participated in the POUNDS LOST study.
According to the authors, this study shows that a low-calorie diet (healthy diet) is what is needed to lose weight and not the proportion of nutrients of the diet. So, it does matter if you follow a high protein low carb diet (Atkins, South Beach) or a low fat diet. What makes you lose weight is the calorie restriction of any type of diet, so the motto Just EAT less is what really matters. After six-month average weigh loss was 13 pounds and 9 pound after 2 years.
Also, all diets were able to reduce risk factors for cardiovascular disease. Regardless of diet type, participants in general experimented a reduction of triglycerides, LDL (bad) cholesterol, and decreased blood pressure. Metabolic syndrome also decreased with all diet types. All these will contribute to a better heart heath and to have less risk of strokes and heart attacks.
The information contained in this study will definitely help nutrition, dietitians, and medical practitioners inform their patients about proper measures to take in order to reduce body weight. Focus should be placed on calorie restriction and not diet type. As long as there is a deficit in calorie intake, weigh loss if possible; no matter if you eat more proteins or more carbohydrates. Although the effect of exercise was not specifically tested it is obvious that it is needed for weight loss.
Frank M. Sacks qt al (2009). Randomized Trial Comparing Fat, Protein, and Carbohydrate Composition of Diets for Weight Loss for Two Years. New England Journal of Medicine. 360:859-873