I think people don’t recognize that obesity is a serious as alcoholism or an addiction to opioids.
The obese people who walk around you are generally not stupid. They are addicted to ultra processed foods that are designed to be addictive.
Some people literally try everything and can’t keep the weight off. It’s not stupidity, it’s a combination of factors including genetics. Obesity is often tied to mental illness and compulsive behavior.
If you can stay lean and lose weight, that’s an amazing blessing. Go enjoy it. There are some others who lose it and cannot keep it up because of the battle with their brains. Just like alcoholism and other addictions.