Christian Bale is one of those gentically gifted body types, evidenced by the fact that he regained all the weight plus some (muscles) for Batmn Begins in like 6 months. Yes he was dedicated but if you do not have that type of body you cannot handle it.
Assuming your fat, why else to people go on "diets", go on an actual diet, as in way of life. Kick out the bad crap and start moving and grooving. No I ain't blowing smoke. 1 month ago I was fate (240, had been 220 before holidays) getting lazy on my diet again, I should be in the 170 range for normal body composition. I finally got pissed off enough with the yoyo dieting over the last 8 years (Where I have been between 220-260lbs). Research the Ketogenic diet since I had noticed that no-carb versus carbs makes me feel much better (the no-carb) and the Ketogenic diet is a way to live sans carbs. Got me some P90X and started rocking. I've lost 20 pounds (34%BF to 27% in a month (figure 10 of water), built 3 lbs of muscle and in general am kicking ass.
Remember if its easy it ain't gonna work because easy means your not working to challenge yoursel/body and that's the only way to get results, if you aren't motivated enough to work out, eat properly for yourself, you aren't going to be during a loose weight diet. Work hard and get pissed at your fat self or shut up and go be fat.
Seriously ain't trying to rag on you as a fat person myself I am try to get you pissed off enough to want the change. Go take pictures of yourself, naked w/o sucking it in and arms at your sides. Then look at them, the mirror lies to you, those pictures, if not the health benefits should get you angry.