I ran into a friend on Shabbos who’s lost about 60 pounds since I first met him in 1994 and he’s kept the weight off for about a decade. I asked him how he did it.
He started talking about controlled portions. He keeps no food in the house. He only eats out because when you eat out, they give you a controlled portion. When you prepare food for yourself at home, you can keep going back for more. He said that McDonalds and Jenny Craig had the same program — controlled portions.
He drinks a lot of seltzer because that makes him feel full and he’s wary of food and drink he can consume in enormous quantities (such as fruit juice, grapes) that won’t fill him up. He says that drinking Coke is probably better than drinking fruit juice because the carbonation of Coke fills you up.
My friend has a theory on why people regain their weight after diets — because they haven’t changed identities. They will diet to reach their desired weight but they don’t regard that dieter as their true self. Once they get their desired weight, they say, I can go back to eating like myself again. But you can’t. If you have weight problems, you can never go back to your habitual way of eating and stay slim.