What Happens to Your Food When You Microwave It?

Microwave ovens are household products that use a form of radiation to heat food quickly and conveniently. Despite the decades-long popularity of microwave ovens, many people still wonder how microwave ovens affect food and whether they are safe to use.

1. Electricity Produces Electromagnetic Waves

A magnetron in the microwave oven uses electricity to produce electromagnetic waves. These waves, called microwaves, cause particles in food to vibrate and absorb power. These vibrations produce heat and cook the food.

2. Water Molecules Are Affected

Water molecules in food are most affected by microwaves. Foods with high water content will usually heat up quicker than foods with low water content. However, fats, sugar, and other food molecules can also absorb microwaves.

3. Conduction Warms the Food

Food is cooked in a microwave through conduction. In this process, food is cooked from the outside in as heat is transferred from the hot outer layers of food to the middle of the food.

4. May Alter the Texture of Select Foods

Microwaving changes the texture of certain foods. Water in foods turns to steam as it is heated. While foods with high water content, like veggies, may become softer, other foods may become too dry if heated in the microwave oven for too long.

5. Help Preserve Nutrients in Food

When used properly, microwave ovens help preserve nutrients in food. Microwaves may also increase certain nutrients, including resistant starch and antioxidants. Some other cooking methods, like boiling, may lead to nutrient losses.

Overall, microwave ovens are considered to be safe and convenient. Plus, there is little concern that using microwave ovens leads to less nutritious foods.

Does Microwaving Food Change Nutritional Value?

A food’s nutritional value may change depending on how it is cooked. However, the degree to which nutritional value changes depends on the food and the cooking method:

• Microwaving food preserves nutrients better than other cooking methods. Compared to high-heat cooking methods, like boiling and frying, microwaving may preserve nutrients better due to its lower temperature and shorter cooking time. One study found that microwaving vegetables retains vitamin C better than blanching and boiling.
• Microwave ovens may cause nutrients in some foods to increase. Some research shows that microwaving increases polysaccharides and antioxidants in certain foods. Microwaving may also increase the amount of resistant starch in some foods, which is beneficial for digestion.
• Some nutrients may be lost if foods are overheated. Water-soluble vitamins, like vitamin C and B vitamins, are especially susceptible to heat and may be degraded if foods stay in the microwave for too long.

The bottom line is that microwaving foods does not cause significant nutrient losses. In some cases, microwaving may even increase the nutritional value of some foods.

Are Microwaves Harmful?

Microwave ovens are generally considered to be safe household appliances, especially when used correctly.

The U.S. Food and Drug Administration (FDA) regulates the manufacture of microwave ovens. This regulation ensures that microwave ovens that you put in your home have passed certain tests and meet FDA standards.

However, despite these regulations, confusion remains surrounding radiation and other safety aspects of microwave ovens:

• Radiation from microwaves is not considered a risk to human health. Microwave ovens use non-ionizing radiation to heat food, which cannot damage cells or DNA like other forms of radiation may. This means that food does not become “radioactive” once it has been in a microwave oven. Ionizing radiation, on the other hand, may cause potential damage when humans are exposed to it at high levels.
• In very rare cases, a leak may increase the risk of radiation exposure. A damaged microwave oven may contain cracks or holes that leak radiation when in use. For this reason, it’s recommended that you discard damaged microwave ovens.
• Proper food containers and dishes should be used in microwave ovens. Plastic containers in particular pose of risk of melting and even leaking potentially harmful chemicals into your food if heated. Research shows that microwave heat releases more microplastics than other forms of food storage or usage.

How to Safely Use a Microwave Oven

Like other forms of cooking, microwaving must be done properly to ensure food safety:

• Microwaving may cause some foods, including meats and large servings of food, to cook unevenly. Uneven cooking may allow potentially harmful bacteria to grow in food. Therefore, it’s important to use a food thermometer to ensure foods have reached proper temperatures after cooking.
• Foods continue to cook even after the microwave oven has turned off. Sometimes, it may be necessary to let foods that have just been microwaved stand for a matter of minutes to allow them to finish cooking. Be sure to follow cooking instructions when using a microwave oven.
• Not all foods or dishes can go in the microwave oven. Metal utensils, aluminum foil, and other materials should not be microwaved. Some foods, like raw vegetables, fruits, and even hot dogs, may cause arcing (sparking) if microwaved.
• Burns are possible when handling microwaved food. Microwaved water may get especially hot and has been known to cause burns and scalding in the cases of improper handling.