No, microwave ovens don't destroy the nutritional value of foods and turn them into toxins

What is the claim?

A viral video shared on Instagram on March 17, 2024 claims that cooking food in a microwave oven is "basically destroying every food value that's in the food and turning it into a toxin." The video has accumulated over 11,000 likes. 

The video shows an interview in which the man being interviewed claims that microwaved food becomes "highly toxic" with zero nutritional value. 

"So it doesn't really matter if you have a bowl of vegetable soup that you warm up in the microwave oven or if you eat cardboard," he says. "It makes no difference. Because the food value is not there anymore and it also becomes toxic." 

This claim is a version of a false claim that repeatedly resurfaces, known in fact-checking as a zombie claim. We have previously debunked similar claims that microwaves can cause cancer and create dangerous radioactive compounds within food. 

And just like those others, this one is also false.

What we found

Logically Facts identified the man being interviewed as Dr. Leonard Coldwell, a motivational speaker and author of numerous books on self-help and natural medicine. Coldwell's official website lists numerous accreditations in the fields of naturopathy and alternative medicine, but he does not appear to be a practicing medical doctor or have any formal medical qualifications.

We found a longer version of the interview uploaded to a YouTube account called iHealthTube.com in August 2012. 

Microwave ovens work by emitting microwaves, a form of low-power electromagnetic radiation similar to radio waves. These waves are absorbed by the water molecules in food, causing the molecules to vibrate and heat up. The radiation is non-ionizing, meaning it does not pose the same health risks as X-rays, which emit ionizing radiation.

The U.S. Food and Drug Administration (FDA) has published an article stating that microwaves are perfectly safe for cooking. "Microwave cooking does not reduce the nutritional value of foods any more than conventional cooking," the article says. "In fact, foods cooked in a microwave oven may keep more of their vitamins and minerals, because microwave ovens can cook more quickly and without adding water." This is because nutrients, particularly vitamin C, are affected by heat. 

Logically Facts has contacted the FDA for comment.

There is data available that indicates that microwave cooking can lead to a higher concentration of a neurotoxin named acrylamide forming in foods than conventional cooking methods. Acrylamide is a chemical compound created during high-temperature cooking formulated from the sugars and amino acids in food. It has been found to cause cancer in animals in studies where animals were exposed to much higher doses than those found in food. 

However, a 2020 paper that looked into the available data found that this depends on the length of time and heat that food is cooked for.

"The published studies showed that microwave heating at a high power level can cause greater AA formation in products than conventional food heat treatment," the paper says. "At the same time, short exposure to microwaves (during blanching and thawing) at low power may even limit the formation of acrylamide during the final heat treatment."

The researchers add that conventional forms of cooking have also been shown to lead to acrylamide formation. In particular, potato frying and roasting, cocoa and coffee roasting, bread and pastry, and cereal heat treatment were linked to the highest levels of acrylamide.

But this doesn't make the foods unsafe for consumption. The FDA advises that consumers adopt a healthy eating plan with a varied diet that "limits saturated fats, trans fats, cholesterol, salt (sodium) and added sugars." 

When it comes to microwave ovens, the agency suggests that consumers adopt "common sense precautions," including using microwave-safe cooking equipment and following the manufacturer's safety instructions. 

The verdict

Claims about microwave safety have been circulating for years, with a recently posted version claiming that microwave cooking reduces the nutritional value of food to zero and turns food into a dangerous toxin. Like the others, this claim is untrue. While some nutrients are lost in the cooking process due to heat exposure, microwave ovens may help some food retain nutrients due to the shorter cooking times. They have also been associated with lower levels of acrylamide formulation than some other high-heat cooking methods. Therefore, we have rated this claim as false.