It's more complicated than "big portions". Anecdata: I very rarely eat in the restaurants (less than once a month), I eat pretty small portions, I am physically

It's more complicated than "big portions". Anecdata: I very rarely eat in the restaurants (less than once a month), I eat pretty small portions, I am physically active at least 5 days a week, still have extra weight which is hard for me to get rid of. There are reasons for that, but saying it's all explained by "portion sizes are too big" is very simplistic and misleading. There are many other factors.