The best way is exercise with reasonable nutrition and strong will. Teach a basic method, don't eat any snacks! Breakfast is mainly milk, fruit and bread, Chinese food is normal (just eat enough), and dinner is mainly vegetables and fruits. You can walk for more than 40 minutes after one and a half hours. Just stick to it.

Losing weight quickly doesn't apply to you, because you haven't done any exercise, and you get scared after practicing for a few days, which is not good for your health!