The calf muscles are what are called slow twitch muscles which means that the calf muscles are, for the most part, made up of slow-twitch muscle fibers, fibers that are best at endurance feats. The gastrocnemius and the soleus run between the knee and the ankle.
Therefore the most common causes of obesity are overeating and physical inactivity. Ultimately, body weight is the result of genetics, metabolism, environment, behavior, and culture. 1  Genetics. 2  A person is more likely to develop obesity if one or both parents are obese. 3  Genetics also affect hormones involved in fat regulation. 4  For example, one genetic cause of obesity is leptin deficiency.
If those calories are not used, the body stores them as fat. Your body will build up fat stores if you continue to eat more calories than your body can use during daily activities and exercise. Obesity and morbid obesity are the result of too much fat being stored in your body. Certain medications, such as antidepressants, can cause weight gain. Medical conditions such as hypothyroidism can also lead to weight gain, but can usually be managed so that they do not lead to obesity.