The five laws of behavioral genetics are:All this means that genes account for much more human behavior than most ppl realize, and family environment counts for less.
All human behavioral traits are heritable
The effect of being raised in the same family is smaller than the effect of the genes.
A substantial portion of the variation in complex human behavioral traits is not accounted for by the effects of genes or families.
A typical human behavioral trait is associated with very many genetic variants, each of which accounts for a very small percentage of the behavioral variability.
All phenotypic relationships are to some degree genetically mediated or confounded.
J-Man would say that obesity is mostly genetic partially because of genes that control fitness and exercise, but mostly because of genes that control behavior like laziness and overeating. You have some theoretical ability to increase exercise, lower consumption, and lose weight, but if your innate personality traits keep you from sticking to a diet, they you will not take advantage of that ability.
He is a determinist, but that doesn't follow from those laws, as those heritable traits are only 40-80% inherited. Some ppl might alter their behavior enuf to live a longer and healthier life, but it is a small percentage and may not be significant in research studies.