2. Skim Milk
One of the largest and longest studies of women's health, the Nurses' Health Study, looked at some 77,761 nurses over 12 years. Those who drank more milk as teenagers had higher rates of severe teenage acne than those who drank less. Skim milk was worse than full-fat milk. Besides the lactose, researchers surmised the presence of hormones and bioactive molecules in the milk might have created adverse skin conditions.
Easy swap: Trade the cow's milk for unsweetened coconut or almond milk.
3. Vegetable Oils
"There are some fats that you should avoid, namely manmade trans fats and omega-6-heavy polyunsaturated fatty acids that are abundant in vegetable oils, like corn and soy, abundant in the modern Western diet and guilty of increasing your risk of heart disease," writes Emily Main. Among its damage, these inflammatory oils wreak havoc on your skin. Studies find acne is primarily an inflammatory disease.
Easy swap: Upgrade to olive oil (sautéing), extra virgin olive oil (drizzling), and coconut oil (medium-heat cooking).
4. Wheat Bread
Manufacturers know "whole grain goodness" triggers a halo effect, but that's simply a marketing term that conveniently overlooks the damage gluten does. Dr. Mark Hyman estimates as many as 30 percent may have non-celiac gluten intolerance. Other studies link numerous problems, including psoriasis, with gluten intolerance.
Easy swap: Look for a gluten-free rice or coconut wrap for sandwich alternatives, and give your carbs a veggie swap.
5. Fruit Smoothies
Sure, they offer a few nutrients, but that's where the good stuff ends. Whether you enjoy it freshly blended, prepackaged, or from a chain-juicing vendor, smoothies provide a sugar overload that rivals a milkshake. Much of it comes from fructose, the dominant sugar in fruit. One study with two groups of rats fed high-fructose diets suffered increased glycation, AGEs, peroxidation, and other skin damage. (The antioxidant alpha-lipoic acid reduced that damage.)
Easy swap: Make your own juice using mostly leafy and cruciferous greens, which you can flavor up with a little lemon or frozen raspberries. Try any of this refreshing green smoothie bowl that'll give you stronger and healthier skin, hair, and nails.
This article origianlly appeared on Women's Health US.