Parents, take note. If you have a child who is overweight -- and if that child is approaching puberty -- now may be the right time to encourage healthier behaviors, including diet and exercise.

That's because puberty marks a critical point in the body's tendency toward obesity. Puberty is the last time that our fat cells can increase significantly in NUMBER (in response to overeating). Beyond puberty, our fat cells can increase or decrease in SIZE, which is what happens when we gain or lose weight. But having a much higher number of fat cells makes lifelong obesity more probable -- and the battle to lose weight all the more difficult.

By building healthy eating and exercise habits early, our children can help avoid weight-related health problems such as heart disease, high blood pressure and diabetes in adulthood.