It works well.
But first you must identify the habits that got you (generic you

) fat. THen hypnotism can help get rid of these habits.
It's not like waving a wand and saying YOU ARE GETTING SLEEPY...YOU WILL GET SKINNY.
Hypnotism is a good aid to behavioral modification. "When you go to the refrigerator you will always ask yourself 'Am I really hungry?'" THat kinda thing.
Or at a buffet you may condition yourself to say to yourself, "Is it to my benefit to eat as much as I can to get my money's worth?"