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The Oils You Might be Cooking with, like Peanut and Vegetable Oils

What's in them: Omega 6 fatty acids

The science: Think of omega-6s as the not-so-healthy yin to omega-3s good-for-you yang. The fat molecules your body makes from omega-6 are pro-inflammatory, while the ones made from omega-3 are anti-inflammatory, according to a review in the Journal of Nutrition and Metabolism. The review authors write that the ideal ratio of omega-6s to -3s is 1 to 4, but in the past few decades, the average person's ratio has shifted to 15 to 1 (can you say yikes?). That could help explain rising rates of chronic inflammatory conditions like cardiovascular disease, non-alcoholic fatty-liver disease, obesity and Alzheimer's disease.

One more thing: Other oils that could throw off your omega-6–to–3 ratio include corn oil, safflower, sunflower, and grape seed, along with condiments like mayonnaise and salad dressings (especially ones that include those oils). If you regularly consume or cook with a lot of these items, shift your fatty acid ratio back in the right direction by cutting back on the 6s and eating more omega-3-rich foods like fatty fish, olive oil and nuts.