Secondhand Fat

On top of suffering from secondhand smoke, research suggests that people who live with smokers may also suffer malnutrition.

After examining data culled by the U.S. Department of Agriculture, Jeffrey S. Hampl, an Arizona State University assistant nutrition professor, found that spouses of smokers' consumed on average three more grams of total fat per 1,000 calories than spouses of nonsmokers'. Their diets were also lacking in fiber and certain vitamins and minerals.

These findings may be partially explained by smokers' tendency to have lower incomes than nonsmokers. "When people have low incomes, they often don't make the best dietary choices," says Hampl. Lower income may also mean lower education and less access to health information—all of which may hinder healthful eating.

What's more, "[smoking] goes hand in hand with unhealthy behavior," Hampl says. "When people smoke, they often rush through their break or take a snack outside so they can smoke."

Smokers' husbands fared the worst, consuming more alcohol and cholesterol than their counterparts with non-smoking spouses. "Women are more health-conscious, more likely to learn about nutrition, and are still reminding their husbands to go to the doctor," Hampl reasons. So when the women step outside for a smoke, their husbands reach for a drink.