There are lots of ways to damage your skin. You can barbecue it for hours in the sun. You can dry it out by washing it with harsh soaps. You can clog your pores by sleeping with your makeup on. However, one of the fastest ways to irritate your skin isn’t from the outside, but from the inside. Eating the wrong foods can wreck your skin—here are the worst culprits:

1. Sugary, high-carb foods. Why are carbs bad for your skin? Because carbs turn into sugar in your body. Sugar, in turn, ramps up your production of AGEs, which stands for advanced glycation end products. These “stiffen” collagen and elastin, damaging your skin and making it harder to repair. The result: You look years older than you are.

What’s more, carbs don’t just age you quickly. In addition, they’re a big contributor to acne.

That last claim may surprise you, because many doctors will tell you that the food-acne connection is a myth. However, several years ago, researchers conducted an extensive literature review and determined that high-carb foods do indeed contribute to acne. They appear to do this by promoting the production of sebum—the oily secretion that fosters acne.

Here’s what Jennifer Burris, the lead author of the study, had to say:

“High glycemic index foods, like white flour, sugary sweetened beverages, and sugar, increase blood glucose more, compared to low glycemic load foods. High glycemic load foods trigger an increase in blood glucose and insulin as well as an increase in insulin-like growth factor-1. These hormones and hyperinsulinemia in turn increase sebum production. It’s like a domino effect.”

So if you want clearer, younger-looking skin, avoid loading your diet with bread, pasta, rice, and other carb bombs. Your skin will thank you—and, as a bonus, you’ll lose extra pounds.

2. Dairy foods. Burris and her team also uncovered another big culprit in acne: dairy. This doesn’t surprise me at all, because for years I’ve been telling my patients with acne to eliminate dairy products—and frequently, the results are amazing.

Interestingly, a new study indicates that consumption of low-fat or skim milk, but not full-fat milk, is associated with acne in teens. This, too, is in line with the advice I give my clients: If you’re going to include dairy in your diet, go for full-fat rather than reduced-fat or fat-free products.

3. Seed oils. Seed oils are high in pro-inflammatory omega-6 fatty acids and low in anti-inflammatory omega-3 fatty acids. (For instance, safflower oil contains no omega-3 at all.) As a result, they contribute to chronic inflammation—and that inflammation translates into blotchy, sick-looking skin.

Moreover, when you use seed oils, you’re skimping on healthy fats that feed your skin cells and make them “bouncy”—for instance, avocado and coconut oil.

And finally, seed oils are over-processed and they’re usually going rancid by the time they reach the grocery store. And needless to say, a rancid food isn’t going to make your skin glow. —

Bottom line? Don’t torture your skin with a high-carb diet, acne-promoting dairy, or inflammatory seed oils. Instead, eat lean proteins, healthy fats, and loads of veggies. Mainline the building blocks of collagen to your skin by drinking bone broth every day. And load up on berries, which are incredibly anti-aging. Show your skin some love, and it’ll love you back by looking younger, clearer, and more radiant.

Keep thinking Big and living BOLD!