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.
Thus, obesity puts a child's health at lifelong higher risk. Causes of childhood obesity. Both genes and environment contribute to obesity, but the interaction is far from simple. Obesity is a complex condition with many interrelated causes. There is significant evidence that obesity is at least partly genetic. Certain ethnic groups are more vulnerable to obesity and obesity-related disorders. Genome-wide association studies show that some genes are associated with a higher body mass index.