> Diet and exercise are indeed not the path to weight loss. This is well known: most fad diets work this way in some fashion or another, and it’s well known that most fad diets fail.

I think you're misunderstanding what I'm saying. I'm not suggesting people go on keto or weight watchers. Those fad diets don't necessarily fail because they're ineffective, although they probably are--they fail because they are highly prescriptive and restrictive and it's difficult for people to actually execute the diet.

What I'm saying is that reducing total food intake for 3 days creates a lasting decrease in appetite. You can prove this to yourself by skipping breakfast for a few days: after a while, you will simply not be hungry at breakfast time.

The best post I've ever seen on weight loss comes from Andrej Karpathy, head of AI at Tesla: https://karpathy.github.io/2020/06/11/biohacking-lite/