If the idea of losing weight by scuba diving sounds too good to be true, rejoice, because it is not. Many experienced divers lose weight during the dive season without changing their lifestyle in any other way. When I go on a dive trip, making several daily dives, I typically return as many as 5 pounds lighter after only a week. And that weight loss comes in spite of consuming ample amounts of food — onboard cuisine is usually plentiful and delicious. So yes, it is possible, at least anecdotally, to lose weight simply by scuba diving.