Sneaky culprits—like the night shift, secondhand smoke, and more—could be affecting your weight


Every day, something new is added to the list of factors that pack on the pounds. People are trying to avoid everything from pesticides to strength training and anything in between. But before you go taking any drastic measures, see what science says. We know the research is out there on the negative effects of junk food, inactivity, and weight gain, but here are some surprising factors that could be affecting your waistline. Science says so! (Stress Eating Adds 11 Extra Pounds a Year.)

Secondhand Smoke



Not only does smoking not make you thin, it can cause weight gain. The American Journal of Physiology has published the evidence on the fattening effects of secondhand smoke. Basically, the lingering smoke in homes triggers ceramide, a small lipid that disrupts normal cell function. How can you avoid this? "Just quit," says Benjamin Bikmam, professor of physiology at Brigham Young University. "Perhaps our research can provide added motivation to learn about the additional harmful effects to loved ones."

The Night Shift



If you're on second shift, you're more prone to gaining weight, says a University of Colorado-Boulder study published in the Proceedings of the National Academy of Sciences. Night workers may expend less energy, so unless people reduce their food intake dramatically, this in itself could lead to weight gain. Mostly though, the dangers of the night shift are linked to our circadian clocks: the natural instinct in all of us to be awake during the day and asleep at night. Shift work goes against our fundamental biology and therefore our ability to regulate fat burning processes. (Sleep Eating is a Real and Dangerous Thing.)




The scientific study of the effects of antibiotics on our bodies is exploding. There is growing speculation that rising rates of obesity, especially in children, may be due in part to increased used of antibiotics, which wipe out the bacteria we need to convert food into energy. New York University is one of the many universities and organizations studying this phenomenon to help people realize that antibiotics have long-term consequences.

(Lack of) Gut Bacteria



A healthy digestive system is loaded with microorganisms and bacteria that not only digest food, but help fight off sickness, produce vitamins, regulate your metabolism, and even your mood. If you're naturally low in these bacteria, or have become low over time due to antibiotics, stress, or poor dietary habits, this will change your body weight regardless of diet and exercise levels, says the study published last year in Science.

By Katie McGrath, CPT-ACSM, HHC