PHILADELPHIA (CBS) – If getting in shape is one of your New Year’s resolutions, you may want to put off the diet and exercise until after this bitter blast has passed.

According to research, people who have less body fat are more likely to get sick in the cold.

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A health professor at Ball State University says a body fat range of 15 to 20 percent is the lowest you should go to remain healthy.

“If you have less fat, you have less insulation,” said Community Health Professor at Ball State University Jagdish Khubchandani. “You can have too much cold inside the heart, liver kidney, internal organs, and then they become dysfunctional.”

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The body fat study also found white women, especially those who are athletic or have been diagnosed with an eating disorder, are at the greatest risk of cold weather illnesses.