Do you know how many calories are in butter and cheese and ice cream? Would you get your dog up in the morning for a cup of coffee and a donut?
The only way you get that fat off is to eat less and exercise more.
If you've got a big gut and you start doing sit-ups you are going to get bigger because you build up the muscle. You've got to get rid of that fat! How do you get rid of fat? By changing your diet.