In the early weeks of a new year, those New Year's resolutions are still fresh in our minds and we're still sure that we're going to follow through. According to ABC News, 45% of Americans make resolutions but only 7% claim success one year later. (For related reading, also take a look at 5 Ways To Get Healthy And Save Thousands A Year.)

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Possibly the most common resolution is to lose weight. With two-thirds of Americans now overweight or obese, many charge themselves with joining the ranks of the healthy. Often, being healthier isn't enough motivation to follow through with your 2011 weight loss goals, so we looked at another possible motivator: money.

What Your Weight Costs You
The annual cost of obesity to the United States is fast approaching $100 billion, but if your goal is to shed the pounds, it might help to know what that extra load is costing you and your family. One study estimates that obesity costs the average woman $8,365, and the average man $6,518, each year.

You may think that the majority of this total comes from the medical bills associated with obesity, but that's far from true. In fact, only $524 for women and $432 for men are directly associated with the medical costs of being overweight. The real costs in this figure will surprise you.

Your Weight Affects Your Career
The Journal of Applied Psychology concluded that women who weigh an average of 104 pounds earn as much as $22,000 more than women of average size. Average size, at the time of the study, was 164 pounds. One theory states that employers may believe that a woman who cares enough to look polished and physically fit would take the same care if they were to work at their company.

Unfortunately for the fairer sex, the standards are different for men. Men can lose the battle of the bulge and earn just as much as their thinner counterparts. In fact, the magic money making weight for men is 207 pounds.

Why the unfair perceptions? Probably because it's generally accepted that men not only gain experience with age but also gain inches on their waistline. While many would say that this is clearly unfair, studies are clear in the fact that your extra pounds could be costing you money, especially if you're female.

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Your Weight Shortens Your Life
Another factor that goes into calculating the cost of obesity is the loss of income due to a shorter life. Severely obese people die 10 years earlier than their normal weight counterparts. Those who are moderately overweight die three years earlier.

This study doesn't take in to account what we already know: Those who are obese miss more work and, on average, cost insurance companies $1,400 extra per year because they are overweight. (For related information, check out Are You Unknowingly Committing Health Insurance Fraud?)

More Weight, More Fuel
Finally, in a very small way, obesity costs more in fuel. The same study that found the financial impact of obesity found that nearly 1 billion extra gallons of gas are consumed each year because of the extra weight in automobiles.

The Bottom Line
Obesity is not only unhealthy for your body, it's equally unhealthy for your bank account. Think of weight loss as an investment. If you were to spend $250 on a gym membership and even $2,000 on a personal trainer each year, you could potentially triple your return on that money. Any investor would get in on that opportunity in a heartbeat.

For the latest financial news, check out Water Cooler Finance: Conflicting Job Reports And A Facebook IPO.