According to the World Health Organisation website: (emphasis mine)
What are common health consequences of overweight and obesity? Raised BMI is a major risk factor for noncommunicable diseases such as:
- cardiovascular diseases (mainly heart disease and stroke), which were the leading cause of death in 2012;
- musculoskeletal disorders (especially osteoarthritis – a highly disabling degenerative disease of the joints);
- some cancers (including endometrial, breast, ovarian, prostate, liver, gallbladder, kidney, and colon)
The risk for these noncommunicable diseases increases, with increases in BMI.
However, according to my observations in life, people with similar eating habits, sometimes tend to react differently and have different body sizes. My reasoning is as follows:
They did experiment on an obese population, using their BMI (a lame calculation based on weight and height) as a discriminating factor. Within that obese population, people with bad eating habits (such as junk food, nibbling, or eating disorders) will be over-represented. And those bad eating habits could just as well be themselves the cause of diabetes and other illnesses (as opposed to obesity alone). In other words, this is a major confounding factor.
Now I would like to know if there's any study based on an overweight population that stuck to healthy eating habits (wholesome food, 3 meals per day of normal quantity), and if that group had more risks of diabetes or other disease than thin people with the same regime. If the above mentioned illnesses are really due to obesity, then this should be the case. But I'm skeptical.
Were two populations with similar food regime, one obese and one not, ever compared?
My point skepticism comes from my suspicion that junk food is the problem, not the fact that some people have different metabolisms.