10 worst foods for your skin

The old saying "you are what you eat" holds true for your health. And, it turns out, your skin. Fill up on junk like refined carbs, sugar, and trans fats, and well, your skin is going to look like it.

"We’re actually learning that poor nutrition is just as bad for your skin as cigarette smoking," said Dr. Patricia Farris, dermatologist and author of “The Sugar Detox.”

A poor diet can cause inflammation, which triggers oxidative stress and in turn damages collagen and DNA, making you look older. Here are the top 10 food offenders to keep off your plate.

MORE: 10 Smoothies For Prettier Skin

Rice Cakes
Once hailed by supermodels--and the women who wanted to be them--as the quintessential fat eraser, we now know that rice cakes cause your blood sugar to soar, which speeds up the formation of wrinkles. How? Your body metabolizes the simple carbs in the cakes the same way it does sugar--by converting them to glucose. Once they've been converted, they stick to wrinkle-fighting proteins like collagen and damage them, said Dr. Valori Treloar, dermatologist and author of “The Clear Skin Diet.”

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Candy
In our candy-heavy culture, adolescence is synonymous with pimples.

"But in countries without diets heavy in processed sugar, kids go through puberty without acne," said Farris.

Even if you're well (well) out of your teen years, this finding is a pretty good indication that the Snickers bar you stash in your desk drawer may be a culprit for your adult breakouts. And to add insult to injury, sugar also degrades collagen and elastin, the proteins that keeps skin soft, supple, and springy. (Need more incentive to kick the sugar habit? Check out our Your Body On Sugar infographic.)

"Healthy" Cereal
Don’t let the virtuous packaging deceive you. While whole grains are generally lower on the glycemic index (a measure of how a food affects blood sugar) compared to white ones, many "healthy" cereals are often highly refined and full of added sugar. And that means they can lead to wrinkle-inducing glucose spikes, said Treloar. (These 19 clean, healthy breakfast foods earn our seal of approval.)

Milk
It may do a body good, but your skin? Not so much. Especially the skim variety.
"Milk can be full of growth hormones and growth factors that remain biologically active even after pasteurization," explained Treloar. "Studies show that they appear to make their way into our blood stream where they can affect insulin, cause inflammation, and ramp up oil production."
The result: breakout city. Population: you. Organic milk may be a good alternative, as it contains only regularly-occurring hormones instead of added ones that are found in non-organic options, though more research is needed to say for certain whether organic options won’t negatively impact skin.

MORE: The Best Sources Of Calcium

Chips
Teeming with refined carbs, these noshes increase the inflammation that triggers DNA- and collagen-damaging oxidative stress. Over time, you’ll notice more fine lines, wrinkles, and aged appearance, said Farris. Plus, according to a 2014 study in The Journal of Drugs in Dermatology, refined carbs are the main culprit in the rise of adult acne cases.

MORE: 10 Highly Effective Solutions For Adult Acne

Secretly Sugary Smoothies
Americans consume an average of 22 teaspoons of sugar per day--roughly three times the recommended amount. Most come from hidden sources of sugar, and one of the biggest culprits is smoothies. But it’s not the natural sugar found in fruit that’s the problem. Store-bought bottled smoothie versions or made-to-order options from chains may include juice, frozen yogurt, or even sherbet in the recipes, all of which are packed with added sugar. If you're making them at home and using only good-for-you ingredients like unsweetened nut milk or yogurt, you're safe from the sugar bomb.

Agave
Billed as a better-for-you sugar alternative, this sweet syrup made from several species of agave plants often packs more fructose than even high fructose corn syrup.

"Fructose is metabolized by your liver where it not only turns into fat, but is much more efficient at breaking down collagen than regular table sugar," said Farris. Meaning that seemingly healthy switch you made by swapping sugar for agave may make crow’s feet more noticeable.

Juices and Sodas
You know that most juices are just sugar delivery vehicles, with many packing as much as a soda. But you may not know that it’s their lack of fiber that makes them such bad news for your skin. Fiber is essential for preventing blood sugar swings that prematurely age skin. Without it, wrinkles will follow.

Fast Food
Choosing drive thru lanes, with their high GI and saturated fat-laden menus, can put you at risk for blemishes. Compared to a low-GI, high protein diet, Western diets (traditionally high GI and heavy on the fast food) were linked to more acne lesions, suggests a study in the Journal of The American Academy of Dermatology.

Margarine
While fats are essential for maintaining supple skin, they’re not all created equal. And some, like the trans fats often found in margarine, may zap hydration. A study in the Journal of the American College of Nutrition found that higher intake of margarine was associated with increased skin wrinkling.