Every year some people attend a few food-based education sessions, sign up for a few exercise classes, turn over a new leaf, and voila a few months later they are at a healthy target weight. According to the obesity statistics, about 50% of the population are able to maintain a healthy weight, and a physique they are  (presumably) comfortable with, without ever seeing a trainer or a weight loss expert. Some people so it seems,  have a natural gift to maintain a balance between food and activity.