I was corresponding with some people who are my height which is UK average height of 5 foot 5 who were double my weight. Also Delia Smith has talked about sugar addiction (I was addicted to chocolate, sweets etc) and have felt much better since giving up junk food. Programmes like radiantrecovery.com and the Promis eating guidelines and indeed diets for diabetics and most healthy eating programmes all consistently recommend a low Gi/GL diet more importantly that helping you lose weight but also to improve mental health and I have certainly felt happier since I stopped eating junk foods. That's more important than weight loss itself in my view.
I suspect some people are over eaters/addicted to sugar and others not and there are genetic factors in that. One test in Kathleen de Maison's book is - you come home. There is a plate of newly baked chocolate chip cookies on the table. You're not hungry. The non sugar addict thinks - those look nice - I might have one later. The sugar addict even though not hungry will start eating her way through them all and that's how I was.
So I think if people gradually reverted to the diet we used to have and indeed I had a as a child, breakfast with enough protein, lunch - meat, veg, good carb, dinner, no snacks we'd be healthier, like the Japanese with brown rice and fish., In other words it's the complexity of diet, the added sugars, even the added sugar substitutes which keep some people hooked on sugar (avoid aspartame, just drink tap water) which can make some people continue to eat unhealthy foods. IN other words some of us may be being slowly poisoned by those pushing sugar on us. I see it all the time - even at the air port checking in at Air Canada what were they handing out to the children... sweets, sugar pushing like cocaine pushing but no one takes seriously addiction to sugar. They just laugh that someone might not be able to stop eating all the chocolate in the house, whereas if she were describing how she was searching through all cupboards to find the last bottle of vodka you'd be sympathetic. Instead weight is just some huge joke.
(Skiing - we just went for a week although I did without effort lose 2 pounds but that must be due to skiing all day rather than sitting at a desk all day).