Image: Overweight © Image Source, Getty Images

Robin Hinch of Long Beach, Calif., didn't have gastric bypass surgery to save money. She did it to be able to move.

At 63 years old and 400 pounds, Hinch couldn't walk more than a few feet without getting winded. She hobbled around with a cane, because her weight was crushing her arthritic knees. Traveling was an ordeal.

Now, six years later and 210 pounds lighter, Hinch can take long walks with her dog "and bend down to pick up his poop." She can fly to visit her partner's family in New Mexico without buying an extra seat. She can run around with her grandchildren, ages 4 and 2. Before, "I didn't have a lap for the baby to sit in."

There was some unexpected financial fallout from Hinch's surgery, though. As the weight dropped off, she spent a small fortune replacing her size 6X clothes.

"I went nuts," she said, chuckling. "I racked up incredible credit card bills. . . . To put on clothes in the morning and have them fit -- what a gift."

Hinch is a friend. We've known each other since we were both reporters at The Orange County Register in the 1990s. And while I'm no fan of overspending, I can tell her this: A few thousand bucks spent on new clothes is a bare fraction or what researchers say her excess weight likely cost over the years.

A George Washington University study added up the medical, disability and lost-productivity costs associated with obesity. The researchers came to this conclusion: Being fat costs a ton of money.

  • The individual cost for being obese is $4,879 a year for women and $2,626 for men. If a woman invested that much every year over a 40-year working career, she'd have more than $1.2 million at retirement, assuming 8% average annual returns. The man would have nearly $700,000.
  • Obesity carries dramatically higher costs than merely being overweight. The researchers found the annual costs of being overweight are $524 for women and $432 for men. "Overweight" is defined as a body mass index (BMI) between 25 and 29, while those with a BMI of 30 or higher are considered obese.

Liz Weston

Liz Weston

The researchers didn't capture all the costs of obesity. For example, they didn't factor in the extra airplane seat many people of size have to buy to travel comfortably -- or the opportunities to travel they simply skip to avoid the hassle.

Although researchers calculated the extra gasoline it takes to haul around overweight and obese people ($8 to $36 a year), they didn't factor in the cost of buying bigger cars. (Hinch bought a minivan, even though her kids were long grown, just to have a vehicle large enough to accommodate her size.) The studies didn't try to track the bigger food and restaurant bills that can come with compulsive eating or the cost of diets or counseling that attempt to address the problem.

Also, the annual costs don't reflect what people actually pay out of pocket. Medical costs make up a big chunk of the total -- 66% of weight-related costs for women and 80% for men -- but insurance may cover much of the expense.

Meanwhile, employers often bear the costs for higher rates of absenteeism and lower productivity related to obesity.

The studies the researchers reviewed all concluded that obese employees are more likely to be absent from work as a result of illness or injury than are normal-weight employees. One study found that in comparison to normal-weight men, severely and morbidly obese men miss two additional days of work per year. Severely and morbidly obese women miss between an additional one and five working days annually.

But obesity is also associated with higher rates of disability, which often leads to lost wages and earlier-than-normal retirements.

Obese workers had a 76% increase in risk for short-term disability compared with a normal-weight employee, the researchers found. (The risk rose 26% for overweight workers compared with their normal-weight colleagues.) Obese employees were more likely to suffer from long-term disabilities and to retire early. Early retirement results in lost wages and lower retirement benefits for most workers.

And then there's the loss of life. Being overweight can shave a few months off your life. Being obese can shave off years. A morbidly obese male's life expectancy is five years less than that of a normal-weight man, while a morbidly obese woman loses four years, on average.

Yet another study (.pdf file), by Ohio State University researcher Jay Zagorsky, found that obesity cramps your wealth, as well. Zagorsky found every one-unit increase in a young person's BMI (from 30 to 31, for example) was associated with an 8% reduction in net worth.

But these, really, are just statistics. Anyone who has suffered from compulsive eating knows that the addiction to food can be far more powerful than any consequences that result. Hinch sees it in the weight-loss surgery support group she still attends, when people who have had the same procedure as she did continue to overeat. Doing so stretches out the pouchlike stomach the surgeons created, and the overeaters gain back weight they'd lost.

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Hinch takes those as cautionary tales and focuses on the many positives of her massive weight loss: her new physical freedom, higher energy levels, lower blood pressure and the fact that she's no longer the target of stares or rude comments. The first time she walked through a department store and realized no one was staring was a revelation.

The daily vigilance her weight loss requires is, she says, a small price to pay for the new life she's been given. She's now a bit of an evangelist for weight-loss surgery.

"My only regret," Hinch said, "is that I didn't know about it earlier."

Liz Weston is the Web's most-read personal-finance writer. She is the author of several books, most recently "The 10 Commandments of Money: Survive and Thrive in the New Economy" (find it on Bing). Weston's award-winning columns appear every Monday and Thursday, exclusively on MSN Money. Join the conversation and send in your financial questions on Liz Weston's Facebook fan page.