Just going to weigh in here quickly...
Obesity is indeed scientific, but it's also "social studies" or sociological, at least partly. In terms of poverty or low income families, we see a high level of obesity. It seems counterintuitive. Why aren't the people skinny when they can't afford food?
It's related to malnourishment. Not just the cost of healthy food, or knowing what it is, but the transportation and storage of food. Imagine taking the bus to get your groceries, with two or more kids, and carrying all your food. Limited storage for food when you get home. An apartment sized freezer.
The stomach also feels fuller with high carb and high fat. Protein is expensive. Forget about fresh fruits and vegetables.
I used to teach nutrition and community kitchens and do mass meals for moms in the inner city. It was tough. What they knew about food wouldn't fill a post-it. But we had to get a huge deep freezer for the kitchen for them to store their meals because they didn't have enough room at home to keep them.
I don't believe in making anyone feel bad about their bodies. No one knows their story. I have a friend who works out hard an hour a day, is extremely active and weighs 190 lbs. That woman is strong. Can flip tractor tires. Very curvy. No health issues at all. How should she live her life? live in a state of dieting? She's already very cautious about her intake. For some, she is unacceptable. I have other friends who would rather "die" than be that weight.