What to do if i am large and i don't know why i think that. suggestions on diet/ exercise plans?

Caloric imbalance: Weight gain occurs usually when there is more caloric intake than metabolism (burning). If your metabolism is slow, you may not have to eat a lot to gain weight. A nutrionist may be able to help you create a diet-and-exercise plan that suits you best. Your primary doctor can also make sure you don't have a hormonal imbalance, which can also cause uncontrolled weight problems.