I actually like the wellness incentive thing my company does.
Basically, you get a blood test and weighed. If your numbers are in the healthy ranges (BMI, blood sugar, etc...) then you get money. If you had improvements from the prior year, you get money. They have alternatives for pregnant women, those with lots of muscle mass, etc for whom the normal ranges are misleading or flat out wrong. Best, I just have to go to the clinic in the basement, they take my insurance, and I have no out of pocket cost for the testing. I'm going later this week. It then take 1-3 months to get the money, and they gross it up so you actually get $300 in your pocket.