Because our society is extremely focused on being thin, it is easy to find information on how to lose weight. It is easy to forget that some people have the opposite problem-they are too thin. Gaining weight can be very tricky for some people, whether it is be because of health problems or just an extremely high metabolism.

Metabolism is a series of chemical reactions in the body that allow the body to grow, reproduce, maintain their structure, and respond to their environments. It is the rate at which the human body burns fat and is the key variable in weight control and weight loss. The speed of metabolism varies greatly from person to person and numerous factors come into account.