It's quite fascinating how many people will strongly object to anything suggesting that being overweight isn't that bad for you. Our fat obsession is primarily an aesthetic and moral one, with the health issue being used as a cudgel. Being extremely overweight can lead to poor health outcomes, but doesn't actually impact your risk of death much. Being moderately overweight isn't really bad for you, and actually reduces your death risk. There also isn't really any evidence that there's a health benefit if extremely overweight people lose that weight. That is, gaining the weight isn't good for them, but it isn't clear that, once gained, losing it will benefit them.
People should eat well and get regular exercise, but actually losing weight and keeping it off is very difficult. If people are focused on that, they're likely to get discouraged and give up on the exercise and healthy eating.