/hell/ - internet death cult

Unfortunately, outside of surgery, not by much. The chest is an area where fat is naturally stored, so unless you can make a significant weight loss (15kg+), your chest won't shrink by much. Depending on your genes, you might have a big chest even when your body-fat ratio is at or below healthy amounts. If you're at a healthy weight, don't try to lose any more. A binder might help, but don't rely on it too often, since it can cause long-term tissue damage. If it's causing you too much discomfort, talk to your doctor about getting top surgery.

Working out and losing weight typically helps, starving too but that's not recommend, of course, for your general health.

depends on if you are a guy or girl honestly. for guys, exercise reduces chest fat and burns the excess that builds up. for girls, it is a bit more complicated but exercise can help clear up excess.

there's binding, but that can get pretty dangerous if you don't know what you're doing

Uhhh