Losing weight can help you with everyday life, especially when playing sports it good to stay fit. Losing weight can help with body image issues and the ways to lose weight can help a persons mental health.
Becoming healthy isn’t easy for many, that means eating healthy (the person is probably in a calorie deficit). So eating more proteins can help a person especially when working out. The less calories (sugars, and carbs) you have the more fat your body will use as energy. So, Maintaining more fat in a diet will help when dramatically losing weight, and working out will help with getting more lean muscle to change the looks of the body.
(Hope this helps)