Using evidence presented in your textbook, explain why the notion that people become obese due to a lack of self-control or willpower is not accurate.

Question

What will be an ideal response?

Answer 1

As indicated by twin and adoption studies, genetics contribute much more to obesity than environment does (correlations of BMIs between identical twins are from .62 to .74). Several genes have been linked to obesity as well, including the obesity gene on chromosome 6, the diabetes gene on chromosome 4, the A allele of the FTO (fat mass and obesity-associated) gene, variants of the MC4R gene, and variants of the Mrap2 gene. In addition, there is evidence that viruses, such as the human adenovirus-36, might cause increased glucose intake by fat cells, contributing to obesity. Similarly, bacteria of the phylum Firmicutes, when taken from an obese human and introduced into the gut of normal-weight mice, resulted in weight gain by increasing the ability to obtain energy from food. Epigenetics also plays a role in obesity, as shown by the impact of maternal food intake when pregnant on obesity risk in offspring. This was demonstrated in mice with a mutation in the agouti gene, who only became obese if the mother did not eat supplements that were high in methyl groups and from the increased obesity risk in children of mothers exposed to famine in the Dutch hunger winter of 1944-1945. Low basal metabolism rate can also contribute to obesity and is not under a person's conscious control.