Pledging to finally shed those pesky 10 pounds -- or more -- could end up saving consumers thousands over the long haul.

Experts say even a slight drop in weight can shave $50 or more from insurance premiums, while joining a gym may trigger rebates of up to $500 from an employer or insurer. Over time, the savings from getting -- and staying -- healthier multiply. "People often overlook their most important asset, which is their ability to earn a living," says Tom Harte, a vice president for the National Association of Health Underwriters. "The longer you can work the better your economic advantage."

Unfortunately, living a healthier lifestyle doesn't always come cheap. A 2011 study published in Health Affairs estimates that the government's new "My Plate" nutritional guidelines could cost consumers an extra $380 in food per year. With initiation fees, joining a gym will cost the average new member another $775 in their first year and $511 each year thereafter, reports the International Health, Racquet & Sportsclub Association.

Still, experts say resolution-makers can easily recoup the outlay, and then some, by getting in shape. Here's how:

Cheaper life insurance

Even a little weight loss could be enough to trigger a preferential premium rate, says Kieran Mullins, vice president of underwriting for MetLife. Like many insurers, MetLife divides applicants into different classes based in part on their height and weight. A 5'4" female who weighs 170 pounds, for example, might see a $70 rate reduction on her premiums -- a savings of 10% to 15% -- by losing just 10 pounds, he says. Consumers losing a significant amount of weight could see savings of as much as 40%. Insurers that require a full health exam may note other fitness benefits like lowered cholesterol and blood pressure, which could also contribute to a better rate, says Steven Weisbart, chief economist for the Insurance Information Institute. Something to keep in mind: Insurers don't usually revise existing policies. Policyholders who get healthier may need to go through the process of applying for a new one.

Lower health-care costs

An overweight person who sheds 10% of his or her body weight and keeps it off can cut lifetime medical costs for hypertension, diabetes, heart disease, stroke and high cholesterol, says the Centers for Disease Control. Projected savings: $2,200 to $5,300. That's especially valuable as more employers move to high-deductible health insurance plans, says Harte. Lower medical bills means fewer out-of-pocket costs toward plan deductibles, which now often top $1,000. It can also let consumers roll over more funds in their health savings accounts, which allow patients to invest pre-tax dollars toward qualified medical expenses.

Better health insurance

Consumers who purchase health insurance independently could see savings of 10% to 20% on their premium bills if they lose weight, Weisbart says.

Those who get their health insurance through an employer are less likely to get a better rate because those premiums are typically calculated for a group. But that could be changing. A 2011 survey by consulting firm Towers Watson found that 12% of U.S. employers have programs in place to reward or penalize employees based on health metrics like body-mass index or cholesterol levels. This year, 38% of employers will have penalties in place, says the survey. In other words, companies might soon charge higher premiums for being overweight or offer a break for hitting certain health targets. "It's an emerging trend," says Harte.

Wellness incentives

Employers and insurers may offer cash and discounts for healthier habits, says Pete McCall, an exercise physiologist for the American Council on Exercise, a fitness education nonprofit that also certifies personal trainers and fitness instructors. Capital Health Plan, for example, offers $150 toward health and fitness center memberships, while Lockheed Martin offers $250. What's more, half of employers offer incentives to take a health assessment screening, which measures current health and fitness and provides suggestions for improvement, says consulting firm Aon Hewitt. Companies may also offer discounted rates for gyms and weight-loss programs along with free wellness coaching, says McCall.