Running,swimming/walking or riding a bike are all good cardio exercises which you can use for belly fat.
Eating healthy and doing cardio and weight machines at the gym helps me! I do all the ab strength machines and I already notice the difference in my stomach. So just stick with a workout plan for yourself and eat healthy. Then you'll be good to go! I know some people take dietary supplements to help get that adrenaline to work out which also helps to lose weight too so that might be an additional option.
How do you know it worked for them long-term? That's the acid test. And you can't stay on Atkins -- not enough veggies. Not enough antioxidants. Eventually you have to go off that one. My point is, though, not that anyone shouldn't try these diets you mention, just that so far no fad diet has proven itself over time. The tried and true still has the best outcomes when people are followed over time. So it's fine if people want to try the commercial diets you champion, but it's also fine if they don't and just eat responsibly. But I still want some of those simple crabs -- the ones I've eaten are so complex to eat.
Any diet that has been proved successful will only work so long as you don't go back to your original eating habits. That goes for the millions of diets proven or not. So don't knock the ones that people have found to work for them.
Gym, why do you only eat stupid crabs? Easier to catch? And you do know you don't have to follow anybody's set diet to eat fewer simple carbs, especially the ones you recommend, one, Atkins, that hasn't prove out in research to product sustained weight or health and the other that is over a dozen different diets and based on faulty history. All you have to do is eat fewer simple carbs to eat fewer simple carbs. But simple crabs, well, how do you tell when a crab is simple? Ask them riddles?