I'm a greybeard so I've had lots of time to try different diet+exercise programs. I was a serious cyclist for a couple decades and during that time, I tied high carb, vegetarian and the 40/30/30 diet that was trendy back in the 90s. Despite being much younger and burning a large # of calories, I still had persistent belly fat, which I attribute to the large # of carbs I inhaled on the bike. 40/30/30 worked better all around though. When I started lifting I went to .8grams of protein per LB of bodyweight and haven't felt the need to try anything else.