The Human race hasn’t just gone through a genetic transformation. Thirty years ago when I was at school there was one fat kid who probably did have a glandular problem, on today’s proportions there would be 300 obese ones.
The program is saying its not their lack of activity. Its the ever increasing quantities of sugar rich food they are encouraged to eat more frequently and in bigger portions.
There’s a big study (mentioned on this show) which essentially suggests that the correlation is not that ‘people aren’t active enough therefore they get fat’, but much more ‘people get fat, which means they stop being active’. So the root cause is diet, but once you get fat it is hard to get thin (which is where the compensation effects and stuff come in).