Understanding how many calories are in foods, how calories from different sources affect the body, and how many to eat is more complex than reading calorie counts on nutrition labels and menus, according to a new book. In the book, Why Calories Count: From Science to Politics, nutrition experts Malden Nesheim and Marion Nestle explain how “the human body does a superb job of making sure that it gets enough calories to meet biological needs but is much less effective at knowing when calories are in excess,” the authors write. “The result is that it is much easier to overeat than to stop eating when you are no longer hungry.” Research has identified at least 100 hormones, enzymes, and chemicals that control appetite in the human body and fight to ensure the brain gets enough sugar calories to function. With the abundance of calorie-laden food available, people often underestimate the amount of calories they consume. The authors promote eating a diet high in fruits and vegetables, lean meats, and whole grains in reasonable portions. In reviewing the research, they point out that no single nutrient, such as high-fructose corn syrup or carbohydrates, results in weight gain. Diets high in protein and fat and low in carbohydrates may be effective because they help regulate appetite, but there are no long-term studies and many people eventually abandon the diet to eat the high-carbohydrate foods they crave. Because it is so difficult to accurately gauge the number of calories consumed, the authors recommend regular weigh-ins to keep track of weight gain and loss. Increasing activity also is an important factor in balancing calorie needs.
