Is Microwave Cooking Unhealthy?

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A microwave often serves as a mom's best friend when juggling kids' busy schedules. If you're worried that microwaving is an unhealthy or unsafe cooking method for your family, put your fears to rest. Other than problems with uneven heating, microwave cooking presents no health risks, according to the U.S. Department of Agriculture. Microwaves produce waves of energy that have a frequency of about 2,450 MHz. The waves cause food molecules -- specifically, water, fats and sugars -- to vibrate about 2.5 million times per second. The friction resulting from these vibrations generates heat, cooking the food.

Thick Foods

The waves of energy in a microwave penetrate food about 1 to 1 1/2 inches, presenting a health concern if you're cooking a thick piece of food, such as a roast. If you microwave on high power, the outer layer of the food will cook faster than its interior. Consequently, you might fail to kill dangerous food-borne pathogens in the center of the food.


Use a low-power setting to cook large pieces of food. For example, a 50-percent power setting is suitable for cooking large cuts of meat, according to the USDA. On high power, a microwave's magnetron, which generates the waves, operates at full capacity. On low power settings, the magnetron cycles on and off. Consequently, low-power settings allow the heat building up in the outer layer of food time to spread to the interior. Power settings on microwaves vary, so consult the manual or contact the manufacturer to determine recommended settings and cooking times for various foods.

Uneven Cooking

Uneven heating can occur at any power setting if you don't shift the position of the food periodically. The waves can heat certain ingredients or sections more than others, leaving some areas undercooked, which presents the health risk of food-borne pathogens. Shift the position of the food halfway through cooking or according to the manufacturer's instructions. For example, turn over layers of food with a spoon to promote uniform heating. Note that uneven heating can occur even in microwaves with rotating turntables. Another way to promote uniform heating is to cover food with plastic wrap or a microwave-safe cover, which traps warm, moist air to cook food evenly. If using plastic wrap, turn back a corner to allow steam to vent.

Radioactivity Debunked

Microwaves use short radio waves to cook food. While this is a form of radiation, it doesn't mean your food becomes radioactive. Microwaves are more similar to television and radio waves than they are to dangerous forms of radiation, such as X-rays and nuclear radiation. In short, microwaving poses no danger of radioactivity in your food.


Allow microwaved foods sufficient time to cool to ensure there are no hot spots. Food manufacturers often supply recommended standing times. Follow these to give heat time to disperse and finish cooking the food. For maximum safety, always use a thermometer to check microwaved food before serving it, as you should with any form of cooking. If you're adding sauces to your meal, such as spaghetti sauce, ranch dressing or Alfredo sauce, pour it onto the meal during the last 30 to 45 seconds of cooking, as sauces cook faster than other foods. Overheating sauces can cause them to pop or burn.