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.
Other conditions can also cause secondary obesity. Childhood obesity occurs when children and adolescents are above the normal body weight for their age and height. Obese children are at risk for long-term problems such as diabetes, hypertension, thyroid problems, and high cholesterol.