7 of 19

Guzzling diet soda

Do it right
Does diet soda make you skinny? One study suggested diet soda drinkers may gain more weight over time than those who don't drink it. It's not clear why, but the brain may anticipate calories when foods taste sugary or fatty, so calorie-free sweeteners may spur people to overconsume later on.

But Burge says awareness is key. "If a dieter were aware that drinking diet sodas may cause cravings later on, I don't think there would be harm [in having one]," she says.

Did you hear that? One a day—meaning you probably shouldn't invest in a diet Coke tap for your kitchen counter if you're serious about weight loss.

Next: Chugging water