Nuts in their raw form are completely healthy, but the minute they are heated in the roasting process, they lose most of their health benefits, explains Traci D. Mitchell, a certified sports nutritionist based in Chicago, Illinois. Why? “The fat in nuts is largely polyunsaturated. Polyunsaturated fats are extremely fragile and oxidize (go bad) very quickly when they're exposed to air and heat. Oxidized fats are a breeding ground for free radicals, and free radicals damage our body much in the same way rust damages a car.”
The Better Pick: Keep eating nuts, says Mitchell; just go for the raw, unroasted varieties for a healthier option.