Everyone is talking about training and nutrition, but what about the approach for the lazy - that is, medications and all kinds of chemosis? From taking many drugs, weight is rapidly leaving (the same fluoxetine), not to mention illegal drugs. On the same amphetamines, you lose weight in a couple of weeks in a way that no miracle diet and exercise can compare for three to four months. Not without harm to health, of course, but quickly and 100% the result will be obvious.
If you devote yourself entirely to the cause, everything will work out. I remember I tried to swing according to the Chris Hemsworth program (the one who is Thor). 2 workouts a day is okay. But to be honest, it's impossible to eat so much, you are already climbing out of you, but you have to eat + huge money at the current exchange rate.
Actors are quite wealthy people, they can afford to hire a personal trainer who draws up a special plan of training and diets.
If you need to gain unhealthy weight, then the actors just eat everything and do not go to classes, but all this, of course, under the supervision of doctors and the same trainers.
Here are more detailed articles:
http://fakty.ua / 178016-dzhared-leto-dlya-roli-transseksuala-boleyucshego-spidom-mne-prishlos-po-nastoyacshemu-golodat (article on how Jared Leto lost weight for his role in the movie "Dallas Buyers Club")
http://www.justlady.ru/articles-137571-kak-pohudel-kristian-beyl (About Christian Bale for the film "The Machinist")