Just Quit It!

Okay, here's a no-brainer: Smoking is bad for you. But you probably never suspected some of the ways in which it's bad. This destructive little habit affects a slew of endocrine glands — pituitary, thyroid, adrenals, testicles, and ovaries — in addition to the lungs, heart, brain, and, oh yeah, every other cell in your body. To give you a breakdown of the metabolic risks, smoking helps cause insulin resistance and drives up your cortisol levels. It can make you infertile and throw your body into menopause years before your time. Smoking is also a huge risk factor for problems with your thyroid. Think quitting will make you fat? I have news for you: Smoking fills your body with a number of pollutants that not only won't help you lose weight but will make you fat. Seriously, people, just don't do it.