Mathematical Model Predicts Effects of Diet and Physical Activity on Childhood Weight
Scientists have created and confirmed the accuracy of a mathematical model that predicts how weight and body fat in children respond to adjustments in diet and physical activity. Excess weight in children can lead to lifelong health problems, such as type 2 diabetes and high blood pressure. However, the amount of energy (calorie) intake that leads to excess weight and development of obesity in growing children has been difficult to quantify. The challenge of taking into consideration healthy weight gain from normal growth has impeded the development of accurate mathematical models to simulate and predict body weight changes in children and adolescents.
NIDDK researchers have now modified a mathematical model, originally designed for and validated in adults, to account for children’s unique physiology, including changes in body composition (the amounts of body fat and other body tissues) as they grow. The researchers analyzed data from children ages 5 to 18 years to create the model, and tested it by comparing predictions to actual changes in children as measured in clinical studies that were not used to build the model. The model accurately simulated observed changes in body composition, energy expenditure, and weight. Model simulations also suggest that obese children may be eating far more calories for each pound gained, compared to adults. For example, children under age 10 were predicted to require more than twice the calories per pound of extra weight than an adult would need to gain a pound. Additionally, the model suggests that there may be therapeutic windows of weight management when children can “outgrow” obesity without requiring weight loss, especially during periods of high growth potential in males who are not severely obese at the onset of treatment. While the model may help to set realistic expectations, a controlled clinical trial will be needed to determine if it is an effective tool for weight management.