I think all y'all are right.
When you eat healthy, you can eat a large salad (lettuce, fresh veggies, with a vinegar/lemon juice dressing) and have a very small amount of calories vs. eating a hamburger. In this case, you could eat MORE and get LESS calories than eating a hamburger.
Nonetheless, the key thing to remember is to loose weight you must burn more calories than you consume.
To put it into perspective, nutrionists have come to the conclusion that roughly 3,500 calories is equal to one pound of fat.
Like Tuffguy said, you also need to exercise. When you don't have a large supply of fat to loose, your body is going to look for muscle to burn, as well. (When you have a large supply of fat to burn, you will burn less muscle) So, if you want to see your abs, loose the fat that is infront of them... but you need to do all-over weight training as well, to keep the lean body tissue.
Best of luck.