Heidi - the only way to lose belly fat is by creating a calorie deficit, which means eating fewer calories than your body requires for exercise and daily activity. That way your body is forced to burn some of its stored fat to meet its energy needs. Unfortunately, we can't control WHERE our bodies will take fat from for fuel - we can't tell ourselves to burn off the belly fat first. Some people seem to lose fat from the head down, some people end up lop-sided for awhile, and everyone seems to lose their problem spot LAST of all.
Crunches will strengthen the ab muscles that are
underneath your belly fat, but can't make the belly fat go away and can't flatten your stomach if there's still fat on top. Fat and muscles are two entirely different parts of your body, and strengthening your ab muscles isn't going to do much to get rid of the fat layer over them. The fitness models in those Ab Roller ads have
extremely low levels of body fat that they achieved through diet, not the Ab Roller. There's a saying that 'abs are made in the kitchen, not the gym' and that means that what you eat is a lot more important for a toned tummy than doing crunches.
Keep in mind, though, that building muscle all over will help boost your metabolism, which is why strength training is an important part of any weight loss program.
