"More than one or two servings of coffee or soft drinks per day have been shown to dull the complexion, make skin more dry and look older," says Eidelman. "Caffeine is a diuretic," he explains, "You go to the bathroom more often draining you of much needed hydration to your body and skin. It's better to use a good quality skin care cream containing caffeine than it is to consume excessive amounts of it."

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If you find yourself adding extra salt to everything, you might want to cut back, as it can dry out your skin. A recent study found that salt may be a contributing factor to certain health conditions, including allergies and eczema.

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"Vitamin A is a popular supplement in controlling acne. It can help acne prone skin by normalizing oil production," says Eidelman. "In those cases, the skin will be more balanced and clearer." There's a downside, though: "Too much vitamin A, usually resulting from the over use of oral supplements, can create changes in vision, appetite and drying of the skin or nails," he explains.

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As Eidelman noted earlier, sugar can lead to a dry complexion — and he's not alone in being wary of the stuff. Sadly, sugar is reviled by many dermatologists: In addition to being potentially drying, it also contributes to the breakdown of collagen (which keeps your complexion bouncy), can lead to breakouts and can even clog your pores.

A sad day for donuts, indeed.

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White rice, bread, and pasta are all high-glycemic carbs, which are just as bad for you as sugar and contribute to the same skin issues. This is a case where swapping out your white rice for brown rice; your white bread for whole wheat bread, can make a big difference.

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