Do you have a reliable source for "majority"?
http://www.nhs.uk/Conditions/Diabetes-type2/Pages/Causes.asp...
Only one of these is "eats too much".
> age – being over the age of 40 (over 25 for south Asian people)
> genetics – having a close relative with the condition (parent, brother or sister)
> weight – being overweight or obese
> ethnicity – being of south Asian, Chinese, African-Caribbean or black African origin (even if you were born in the UK)