Lose weight and get promoted in 2013

(MoneyWatch) Research has suggested that women who are overweight are less likely to be promoted than their fitter counterparts. Furthermore, being obese (packing an extra 30 pounds) negatively impacts both genders in terms of success. Here are five reasons that may inspire you to get into better shape this winter -- and in line for career success this year.

You'll look like a leader.

It's not fair, but people have a picture in their minds of what a leader looks like -- and they look like they're in fighting shape. "Shedding a few pounds thus is likely to promote positive prototypes, such as disciplined or professional, which can only help one's promotability," says Angelo Kinicki, PhD, professor of management at the W.P. Carey School of Business.

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You'll be "the face" your company wants to portray.

Employees need to represent their company, and managers consider this when they hire or promote you. "If heavier employees are being considered for a client-facing role or to represent the company in a leadership capacity, the issue may have nothing at all to do with their talent, ability, or motivation. While their weight may be tolerated within the company, it may be an embarrassment when it comes to meeting potential new clients," says Roy Cohen, career coach and author of "The Wall Street Professional's Survival Guide."

You'll fit into the company culture.

Is your company promoting wellness initiatives, like offering free yoga or flu shots? Then get on board, and lose the belly. "For companies that are committed to supporting good health and wellness initiatives, being fat defies the company mission and its core values. Fat employees will stand out and apart as an example of failure," says Cohen. Get fit, and fit in.

You'll show that you're mentally strong.

Losing weight and keeping it off isn't easy, and doing so shows discipline. But falling off the wagon can have the opposite effect. "One of my clients, a banker, lost a lot of weight quickly. Only a few months later her weight ballooned and she was heavier than before. Her boss, a fitness fanatic, assumed she was unable to handle the stress of the job and began systematically to shrink the scope of my client's role. When cutbacks were announced, it was not a surprise that my client's name was on the list," says Cohen.

You'll look less like a liability.

Someone who doesn't keep themselves at a healthy weight may seem more likely to use sick days, and this will cost your company time and money. That's why corporations fund preventative measures like reduced-price gym memberships. "Extra weight means someone will most likely be limited in what they can do and accomplish. It usually causes health issues from diabetes to cancer to heart problems, along with a lack of energy and often difficulty concentrating, focusing, and in thinking optimally," says Ronald Kaufman, author of "Anatomy of Success." So take this winter to get your weight -- and your career -- back on track.