Eating too much and not exercising may be the main causes of obesity, but it turns out they aren't the only things that build the bulge.

Studies have shown the most unexpected things can pack on pounds — from getting your tonsils out, to having a whole array of “obesity genes.”

These days, 1 in 3 U.S. adults is overweight or obese, according to the Centers for Disease Control and Prevention, so every factor counts in the fight against extra pounds.

Take a look at 11 surprising things that could be making you gain weight.