I'm 66, I've tried so many "plans", I've lost count. I have read a lot in recent years and seriously considered the claims of all the different authors and self proclaimed experts. I am now convinced that eating food from simple ingredients is key. I do not eat anything "factory made" Everything is cooked from scratch, I've cut out wheat in all forms, sugar, rice and dairy - still missing my cheese very much. Currently doing an Elimination Diet, which has meant cutting out my beloved black coffee too.
I can say for certain that since the "experts" invented Low Fat the population has become fatter, since the American Food and Drink chains arrived on our high streets, the population has got fatter. I do not believe that nature made food to harm us - but manufacturers do. As children we had a TREAT of a biscuit sometimes, maybe a custard cream or a bourbon, now I see toddlers in pushchairs eating a cookie the size of a saucer. We used to have fairy cakes on Sundays - now small children are given Muffins daily - about 3 times the size.