When you were a teen, your mom probably told you that chocolate causes pimples. Well, she was right, sort of. Chocolate, as in the actual cacao bean itself, doesn’t cause acne. But there is evidence that both sugar and dairy can cause hormone fluctuations and increase inflammation, and both of these things are bad news bears for your skin. So if your mom was thinking of sweet milk chocolate when she warned you away, she was the bearer of wisdom.

It’s the holiday season, which tends to be a time of indulgence for food and drink. But a lot of our favorite goodies—pies, wine, cheese, pastries, hot chocolate and egg nog, to name a few—are full of ingredients that can be common messy skin culprits.

Let’s start with dairy. The older we get, the less effectively our bodies break down lactose. This means that dairy can leave you feeling bloated and sluggish. It can also contribute to mucus build-up and sinus problems, and it can leave your skin red and blotchy. There is some evidence that skim milk is more disruptive to skin than whole milk, so your first move may be to switch to full-fat dairy products. But if you have stubborn acne on your chin, cheeks, or forehead, you may want to try cutting dairy altogether for two weeks, to see if the issue resolves. Additionally, dairy can cause your eyes to appear swollen or ringed with dark circles.

On to gluten. Oh gluten! We love you, and we hate you because we love you! Forehead blemishes are a tale-tell sign that you and gluten may not perfectly gel. Gluten may also cause acne or dark patches in your chin or cheek area. And gluten tends to make you feel puffy—in the belly and in the face.

A small percentage of people have celiac disease, which is a severe and potentially dangerous gluten intolerance. About 15-25% of celiac sufferers break out in dermatitis herpetiformis, an itchy, burning rash, when they consume gluten.

Gluten has also been shown to aggravate psoriasis and eczema, two other skin diseases.

Many of us are slightly gluten-intolerant. This means that gluten may cause inflammation in our digestive systems, which hypes up our immune system. This, in turn, causes our skin cells to produce pigmentation. And random pigmentation leads to uneven, patchy skin. Digestive inflammation may also lead to poor nutrient absorption, which can make skin dull and dry.

Ok, sugar-face! It sounds like a term of endearment, doesn’t it? But there’s nothing sweet about sugar-face. More and more evidence indicates that sugar is bad for us, period. And sugar straight-up contributes wrinkles, particularly on the forehead. Excess glucose molecules cling to collagen, causing it to become stiff and oddly shaped. Consuming lots of sugar can lead to hollow cheeks, eye bags, and thin, pasty skin. It can also aggravate acne, because hello inflammation! Refined sugar has no nutritional value. Whenever possible, steer clear!

Wine & cocktails & beers, oh my! It’s party-season, and for many of us, parties mean an uptick in our alcoholic beverage consumption. But before you sip, consider your skin. When you metabolize alcohol, your liver releases something called acetaldehyde, which is toxic to body tissues. Acetaldehyde results in inflamed, dehydrated skin—and dry skin leads to premature wrinkles. Alcohol also causes your body to release a histamine that dilates the blood vessels just beneath your skin, which is why your face may appear flushed while drinking. If you drink often enough, this redness becomes your skin’s permanent hue. And alcohol dilates pores, which can lead to whiteheads and blackheads.

If you know you’re not going to give up drinking, drink wine rather than beer. Wine has less additives, so it’s easier for your body to process. And drink water while you drink alcohol, to minimize the dehydration effects. You should always avoid drinking before bed, because alcohol definitely messes with your sleep cycle. And your body needs solid sleep to repair and replenish skin.