To be more specific, don't sleep late in the morning. You must have breakfast when you get up in the morning, and you can have lunch later around two or three o'clock, so you won't feel hungry if you don't have dinner at night. Try not to eat at night, and it is best not to eat for six hours before going to bed. Pay attention to diet and try not to eat fried, sweet, greasy food, fat and so on. If you can soak some Chinese medicine (lotus leaf or cassia seed) in water, drink two large cups every day.
I can't say it's absolutely effective. That's what I'm doing now anyway. After two weeks, I lost six pounds, and I'm still going on.
If you can persist, it should be no problem to reduce 50kg at the beginning of school. Come on ~ ~