Well if you'd watch the movie and read the sources, you'd see that there is not much difference in the amount of calories you burn exercising or sitting at a desk. Consequently you won't loose weight one way or another.

Weight seems to be almost exclusively about the calories you ingest. It has little to do with obesity causing less exercise or the other way around. There is not a swathe of pathological things we do that contribute. We eat too much.

I also found that surprising. You can exercise without changing your diet, but you won't loose (much) weight. You can sit at a desk and start eating less and loose a lot of weight.