At first look, the reason for obesity is simple: If one eats more calories than he/she consumes, the body stores the extra calories as fat. As fat collected, body weight increases. From this point of view, human genes are insignificant to his or her body weight. Truth be told, however, obesity reflects the overall effect of genes and the environment.
A few genes are related with obesity. One of the famous example is Leptin-coding gene, which is a hormone that suppress appetite and hunger. People who acquire mutant alleles of leptin-gene will never feel completely full, therefore its prompting overindulge and obesity.
Like genetic factors, the environment can likewise effects the gene expression of human being. For instance, researchers have revealed that mother who consume lower level of carbohydrates and foods deliver babies who are likely to be end up with obesity in adult ages. This finding showed that uterus (mother’s womb) constantly changing genetic expression forms in a developing baby.
Babies in the mom’s womb probably use mother’s eating routine to get ready signal the condition which they will be introduced to. These changes happens during fetal period and give the baby higher chance of living. However, if a baby who prepared for food shortage delivered into an abundant food environment, it is possible to become an obese person.