Little known fact: You can save tax money by losing weight. Seriously. According to TIME Magazine and a 2008 study in the Journal of the American Medical Association, dieters with financial incentives are five times more likely to lose weight.

To get in on the act, turn to the IRS.

Taxpayers can actually deduct the cost of weight loss programs that cost more than 7.5% of their adjusted gross income. For example, someone who makes $45,000 can deduct weight loss expenses above $3,375 from their taxes.

All programs must be recommended by your doctor, who must confirm that your current weight is a threat to your health. Approved expenses include behavioral counseling, appointments with physicians, dietitians and nutritionists, commercial programs for weight-loss and maintenance, gastric banding or bypass surgery, and FDA-approved weight-loss drugs.

Unfortunately, dietary food programs like Nutrisystem don’t count. Neither does liposuction, or general membership dues for a gym, health club, or spa. However, if your gym, health club or spa features a commercial program specifically for weight loss, you can deduct enrollment fees in those specific weight loss programs. Read more about weight loss incentives on the IRS website for more details.

For a more detailed list on what is and isn’t deductible, check out this blog entry from Turbo Tax.

Keep full documentation, so get your doctor’s instructions in writing, make sure your plan qualifies, and hold on to all receipts.