I’ve seen it with my own eyes in my own family. I’ve known what all of these people eat and what they do on a daily basis. We have an endomorphic line and a more mesomorphic/ectomorphic line. There is NO QUESTION that there are far more important factors than diet and exercise.
And chemicals and hormones don’t cause food addictions that I know of; they affect how the body holds onto calories.
It’s easy to be judgmental when you’re the one with a fast metabolism and a naturally high energy level; not so easy for those whose bodies store all of their calories as opposed to converting them to kinetic energy right away.
You know those studies showing that people who bounce their legs and squirm around a lot tend to be lighter? They’re not lighter because they move around; they move around because their bodies *automatically* convert the calories to kinetic energy…they can’t keep themselves from moving. OTOH, there are others who have to intentionally focus on making every movement, with every limb feeling exceptionally heavy and every movement requiring exhausting, deliberate action (those who some ignorant types might call “lazy”). This isn’t because some people are choosing to be “lazy,” their bodies are trying to store those calories, instead of burning them off!