There are many trial fitness CPA offers in hydranetwork and marketleverage.U can also checkout markethealth.com
There are a ton of diet offers on Neverblue Ads, as for fitness, I know Commission Junction has a few.
jMark, are you interested in selling equipment? I have several affiliates making six figures doing it, primarily reviews.
We also have plenty of these. Weightloss campaigns can perform particularly well and can have high CPA values.
For effective results you really need to have a better gauge of your visitors and what they would want. Fitness/weight loss is a big industry with many products on offer.
Give Proactol a try. It is included in the MoreNiche network. You can find positive reviews of the program here on the forum. Proactol has recently launched recession discountsand campaigns comparing it to other diet pills, like Alli, Phentermine and Hoodia Gordonii. Commissions range from $20 (1 month supply) to $130 (8 month supply).