Science shows that genetics act a part in obesity. Genes can directly
source obesity in disease like Bardet-Biedl disorder and Prader-Willi disorder.
However genes do not consistently foresee future health. Genes and habits may
both be required for an individual to be obese. Like many other medical
conditions, obesity is the result of interplay between environmental and
genetic factors. Studies have identified variants in several genes that may
contribute to weight gain and body fat distribution; although, only in a few
cases are genes the primary cause of obesity. Polymorphisms in various genes
controlling appetite and metabolism predispose to obesity under certain dietary
conditions. The percentage of obesity that can be attributed to genetics varies
widely, depending on the population examined, from 6% to 85%.As of 2006, more
than 41 sites on the human genome have been linked to the development of
obesity when a favourable environment is present. The involvement of genetic
factors in the development of obesity is estimated to be 40–70%.