Ultimately losing weight is just about physical exercise and calorie intake.
You know what's a really cool documentary to watch to see people actually lose weight and gain muscle mass?
Blizzard: Race to the Pole was a modern recreation of the 1912 race to be the first to the South Pole between a Norwegian and a British team. They started off with a bunch of athletic but mildy overweight and flabby guys and sent them to trek to the South Pole based on 1912 rations which we now know were not caloric-ally sufficient but all they are eating are basically dried biscuits, pemmican (dried meat and berries mixed into a lot of fat), and butter and cocoa for several months the whole way. They come out thin and pretty ripped in comparison to when they started. The 1912 team died though...