More than likely lack of exercise and taking in far more calories than the body burns is the leading cause of obesity.
Advice:
1. Pray to God as one in Christ (see tag) to be healthy and not be fat, loose needed weight, etc.
2. Eat in due season, for strength, and not for drunkenness, meaning as a rule we only eat when we become too weak to do what we need to do, and only what we need (small amounts) to regain our strength, and normally do not eat much of foods that are heavy in fat calories, regardless of what the clock says, or bcz you we simply want the pleasure of eating. If you eat too much, do not eat again until you are getting weak from lack of food.
3. Thank God for good health and weight, but do not be self-satisfied or glory in yourself, but rejoice in the Lord and give Him thanks and glory as unworthy but beloved and blessed (in Christ) servants.