Beyond Willpower: Diet Quality and Quantity Matter
It’s no secret that the amount of calories people eat and drink has a direct impact on their weight: Consume the same number of calories that the body burns over time, and weight stays stable. Consume more than the body burns, weight goes up. Less, weight goes down. But what about the type of calories: Does it matter whether they come from specific nutrients—fat, protein, or carbohydrate? Specific foods—whole grains or potato chips? Specific diets—the Mediterranean diet or the “Twinkie” diet? And what about when or where people consume their calories: Does eating breakfast make it easier to control weight? Does eating at fast-food restaurants make it harder?
There’s ample research on foods and diet patterns that protect against heart disease, stroke, diabetes, and other chronic conditions. The good news is that many of the foods that help prevent disease also seem to help with weight control—foods like whole grains, vegetables, fruits, and nuts. And many of the foods that increase disease risk—chief among them, refined grains and sugary drinks—are also factors in weight gain.Conventional wisdom says that since a calorie is a calorie, regardless of its source, the best advice for weight control is simply to eat less and exercise more. Yet emerging research suggests that some foods and eating patterns may make it easier to keep calories in check, while others may make people more likely to overeat.
This article briefly reviews the research on dietary intake and weight control, highlighting diet strategies that also help prevent chronic disease.
When people eat controlled diets in laboratory studies, the percentage of calories from fat, protein, and carbohydrate do not seem to matter for weight loss. In studies where people can freely choose what they eat, there may be some benefits to a higher protein, lower carbohydrate approach. For chronic disease prevention, though, the quality and food sources of these nutrients matters more than their relative quantity in the diet. And the latest research suggests that the same diet quality message applies for weight control.
The aim of the Harvard School of Public Health Obesity Prevention Source Web site is to provide timely information about obesity’s global causes, consequences, prevention, and control, for the public, health and public health practitioners, business and community leaders, and policymakers. The contents of this Web site are not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this Web site. The Web site’s obesity prevention policy recommendations are based primarily on a review of U.S. expert guidance, unless otherwise indicated; in other countries, different policy approaches may be needed to achieve improvements in food and physical activity environments, so that healthy choices are easy choices, for all.