In general, microwaving is the healthiest cooking method. However, for individual vegetables, optimal cooking methods vary. The benefits of raw broccoli can be replicated by pre-chopping and letting it stand before cooking. It is a myth that raw foods are always better. Although some nutrients are partially destroyed by cooking, others may become more absorbable. Kale, for instance, may be healthier cooked. In fact, too many raw cruciferous vegetables can be dangerous (but only taken to an extreme). There are several carcinogens created when cooking at high temperatures, though. Cooking animal foods may drive the production of harmful advanced glycation end-products. Frying or cooking meats also makes them particularly carcinogenic. Roasting chicken produces carcinogenic compounds (but not coffee or veggie burgers). Deep frying pollution can in fact be toxic to breathe.
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