What is the biological basis of obesity?

Body fat to mucsle ratio. You can have your body fat checked. For men it should be from 10% to 15%, women on the other hand is a little higher I think 12% to 17% but on this one for women I'm not completely sure. If your within this range your not obese your within your normal range regardless of your weight.

Eating too many Pies !!
biological?
not sure there is.

it's an individual choice.
every1 knows if u eat 2 much u get fat,
don't they?
it's a sad state of affairs with no obvious cure other than 2 eat what u need & no more.

but i hope some1 else can supply u with an answer.
BMI s ratios R misleading.
http://news.bbc.co.uk/1/hi/magazine/6040...
Quantity of calories uptaken equals increase in body mass index.
Body Mass Index.