The reason Gov. Romney passed Romneycare as governor of Massachusetts in 2006 was because many Republicans viewed health care reform mandates and all as a way to inoculate against Democratic charges that Republicans didn't care about people who lacked health insurance.
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.