> being overweight is almost always extremely unhealthy and a major cause of many illnesses
This is not true whatsoever. Weight and health have only limited correlations, to say that being overweight means you are unhealthy is ludicrous. This is well studied and known.
This is just not true. Being overweight or obese significantly increases all cause mortality. Here's a study where they followed 527,265 people for 10 years:
"During a maximum follow-up of 10 years through 2005, 61,317 participants (42,173 men and 19,144 women) died. Initial analyses showed an increased risk of death for the highest and lowest categories of BMI among both men and women, in all racial or ethnic groups, and at all ages. When the analysis was restricted to healthy people who had never smoked, the risk of death was associated with both overweight and obesity among men and women. In analyses of BMI during midlife (age of 50 years) among those who had never smoked, the associations became stronger, with the risk of death increasing by 20 to 40 percent among overweight persons and by two to at least three times among obese persons; the risk of death among underweight persons was attenuated."
Did you even read the full results of this study? Only extreme BMI categories had strong correlations for increased risk of death and mostly for those who didn't have a chronic health condition at 50 already:
"Among all men and women, including smokers and those with preexisting disease, there was a U-shaped relation between current BMI and the risk of death, with the highest risk in the lowest and the highest categories of BMI. Overweight was not associated with an increased risk of death among men but was weakly associated with an increased risk of death among women."
Note that the highest and lowest categories were extreme values of weight for an individual and there were significantly fewer people in those categories compared to the others.
Moreover, the authors of this study even talk about being overweight vs. obesity in the discussion section:
"However, whether moderate elevations in BMI (i.e., overweight) truly increase the risk of death is controversial.2 Several studies reported no increase in the risk of death among overweight subjects even after those who died during the initial years of follow-up were excluded or subjects were stratified according to smoking status.25-29 Recently, Flegal et al. reported that overweight was not associated with an excess risk of death in the nationally representative samples of U.S. adults drawn from the National Health and Nutrition Examination Survey."
They go on to talk about possibilities regarding smokers with the data from this study.
Finally, it is worth nothing that this study follow those aged 50 and older and did so through the AARP's health survey and is specifically focused on the health of older people and that is only looking at correlations for individuals who are already at a higher risk of dying in the first place.
Yes, I did. I don't think you're interpreting the results correctly. The conclusion of the paper, in summary of all the evidence, is that "Even against the background of advances in the management of obesity-related chronic diseases in the past few decades, our findings suggest that adiposity, including overweight, is associated with an increased risk of death."
Please look at the figures, in particular figures 1 and 2 D/C. Among non-smokers, as the BMI increases from 25 there is an increased risk of death. You can see the trend clear as day.
This is not true whatsoever. Weight and health have only limited correlations, to say that being overweight means you are unhealthy is ludicrous. This is well studied and known.