I mean, we're overweight in significant part because being overweight is simply a defined point. It's based on 1970s statistical analysis of the weights of straight white men. It's defined based on BMI, a statistical scale, and not based on any kind of weight threshold where we start seeing a meaningful phase shift in outcomes. You could get rid of a lot of obesity by just raising the setpoint of "obese" on the scales and your new system wouldn't necessarily be more or less medically sound/evidence based than the current one.

Even this article is making sweeping claims based on a tiny cohort of a nondiverse group of people. It's... just not interesting science. Very little science around weight is particularly good. Worse, it has some really obvious logical flaws. There's an implication here that eating fewer carbs increases your risk of death -- it could be the opposite, that people who are more likely to die eat fewer carbs. There's a reason people use the word "healthy" to describe big appetites -- not because gorging yourself is good, but because poor appetite is an almost universal sign of bad health. And the "40% increase" in cancer from high-fat diets may represent a very small increase in actual total risk of cancer because these factors are already so damned low.

Most people should just worry a lot less about how fat other people are because it's really none of their business. We should be making sure people have access to healthy, fresh food and that processed food companies face strict regulatory oversight for predatory practices just because keeping people fed well is something we value, not because we hate fatness.