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.
Lack of Exercise. Other reason why obesity exists is the lack of physical activity. This lack of exercise is because people have a busy life style. For example, they work all of time and not have a break to exercising. Also, people have a sedentary life and they prefer to be watching TV or playing videogames for a long time.