Calorie Balance

"Achieving and sustaining appropriate body weight across the lifespan is vital to maintaining good health and quality of life. Many behavioral, environmental, and genetic factors affect a person’s body weight. Calorie balance over time is the key to weight management. Calorie balance refers to the relationship between calories consumed from foods and beverages and calories expended in normal body functions, such as metabolic processes, and through physical activity. People cannot control the calories expended in metabolic processes, but they can control what they eat and drink, as well as how many calories they use in physical activity. Calories consumed must equal calories expended for a person to maintain the same body weight. Consuming more calories than expended results in weight gain, while consuming fewer calories than expended results in weight loss. This can be achieved over time by eating fewer calories, being more physically active, or, best of all, a combination of the two. Maintaining a healthy body weight and preventing excess weight gain throughout the lifespan are preferable to losing weight after weight gain. Once a person becomes obese, reducing body weight back to a healthy range requires significant effort over time, even years. People who are most successful at losing weight and keeping it off do so through continued attention to calorie balance. Americans need to decrease the total number of calories they consume from foods and beverages and increase calorie expenditure through physical activity. Achieving these goals requires selecting a healthy eating pattern that includes nutrient-dense foods and beverages, meets nutrient requirements, and stays within calorie needs. Americans can also choose from a variety of strategies to increase physical activity. Key recommendations include preventing and reducing overweight and obesity through improved eating and physical activity behaviors; controlling total calorie intake to manage body weight; increasing physical activity and reducing time spent in sedentary behaviors; and maintaining appropriate calorie balance during childhood, adolescence, adulthood, pregnancy and breastfeeding, and older age."