Are Microwaves Safe?

Why I Don't Own One and How I Reheat Food

When I was a teenager, my mom attended a nutrition class. When she got home from said class, she grabbed our microwave and threw it away. From that day on, she reheated our leftovers on the stove or in the oven. About six months later, my dad grew tired of the “inconvenience” so he bought another microwave, but my mom continued to reheat our food without using it. (Funnily enough, in recent years, my dad has also become “crunchy”—raw milk and everything!—and gave his microwave away! LOL sometimes, we just gotta trust the moms in our life.)

After leaving my parent’s home when I was 18, I continued to be suspicious of microwaves but I used them anyway for several reasons: living in dorms, not wanting to dirty a pan, wanting the convenience of a quick heating source, etc. It wasn’t until my full-blown crunchy conversion that I decided to stop using my microwave. And when we moved last August 2023, our new home didn’t even come with one and I never bothered to buy one.

How Microwaves Work

Microwaves heat food very differently from a regular oven, convection oven, or stove top. All of the latter options slowly heat your food from the outside in. That’s why you can stick a casserole in the oven and after 20 minutes, the outside might be warm, but the inside is still cold. Hot air is circulated around a food until it becomes hot, it’s that simple.

On the other hand, microwaves heat food from the inside out. The mirco-waves in a microwave force the water molecules in a food to violently bounce around the food so quickly that the entire meal is steaming hot in 30 seconds to one minute.

Some “experts” believe that microwaving foods is actually a better way to preserve nutrients in food because the food is exposed to heat for less time. But I don’t buy that. The food is exposed to heat for less time because the bouncing/vibrations are so violent and fast, as opposed to an oven that heats a food slowly and more gently.

It’s the same reason milk that is pasteurized at a lower temperature retains more of its original nutrients even though it is heated for a longer amount of time (30 minutes vs. 15 seconds), while pasteurized and ultra-pasteurized milk is heated for a lot less time but at a higher temperature. The latter two are completely sterile (which is why a synthetic version of vitamin D is added back in) and shelf-stable (if unopened, they could sit on your counter—why do you think some milk in the grocery store is not refrigerated? Ultra-pasteurized milk sits in a fridge at the grocery store for show because customers would be suspicious if all of it sat on an aisle shelf).

Let’s look at more research before you take my word for it . . .

Are Microwaves Really That Unsafe?

Here’s the truth: I don’t know for sure. BUT, I have found a lot of good evidence from research (and critical thinking) to convince me that, because of the more aggressive form of heating, microwaves denature our food and destroys it’s nutritional profile.

Let’s look at that research . . .

This one is probably the most convincing for me: According to this peer-reviewed scientific journal, microwaving milk caused oxidative damage to the proteins in the milk. Microwaving the milk caused more damage than simply boiling it. This makes it obvious to me that microwaving food isn’t completely harmless. At the very least, microwaving changes the structural makeup of the nutrients in our foods and denatures them into something our bodies don’t recognize.

But the most concerning part of this research was what happened to the rats after consuming the milk that contained milk proteins with oxidative damage:

“Feeding diets containing oxidized milk powder to SD rats caused increased oxidative stress in the brain, deposition of protein oxidation products, downregulation of learning and memory-associated genes, and upregulation of inflammation and apoptosis genes, which eventually led to problems with behavioral spatial learning and memory.”

Whoa . . .

Let’s sidebar super fast and talk about what oxidative stress is because I think it’s important to this conversation.

What is Oxidative Stress?

If you’ve ever heard the terms “free radicals” (bad) and “antioxidants” (good) then you have an idea of what happens when our bodies experience oxidative stress. I think the National Cancer Institute has the easiest to understand definition:

“A condition that may occur when there are too many unstable molecules called free radicals in the body and not enough antioxidants to get rid of them. This can lead to cell and tissue damage.”

This is why we’re always told to eat the fruits that are high in antioxidants, because they can help detoxify these free radicals that might be roaming around in our bodies.

So, back to our microwave conversation: after consuming milk that had been microwaved (and thus contained denatured proteins), the rats in the study above experienced increased oxidative stress in the brain. Can you imagine what kind of symptoms you would experience if you had oxidative stress in your brain? I’m imagining brain fog, memory loss, ADHD symptoms, dementia, even cancer. And this was just ONE of the many adverse reactions the rats had.

More Clues That Led to My Decision Not to Use Microwaves

The research by RCS above wasn’t the only factor in my decision. Here are a few other reasons I became convinced that microwaves just ruin our food:

• The CDC advises parents not to microwave breastmilk “because microwaves can destroy nutrients in breastmilk.” If it destroys nutrients in breastmilk, why wouldn’t it also destroy nutrients in food? The FDA contradicts this advice by telling us that microwaves do not reduce nutritional value of food . . . so who’s correct, here?

• Also connected to breastmilk: I remember as a breastfeeding mom, pediatricians and lactation consultants advising me to “gently swirl” my breastmilk that has been sitting in the fridge in a figure 8 motion before serving it. It must be stirred because, like non-homogenized cow’s milk, the fat of the milk will separate and rise to the top. The fat is a super important nutrient for your baby, so you definitely want it included. These professionals always advised against shaking the breastmilk up and down too quickly because it could damage the sensitive components of the milk. I believe the same idea is true for all of our food. Gently reheating food allows it to slowly warm without too much damage.

How I Reheat Food

Okay, so I don’t own a microwave, that must mean I eat cold food all the time, right? Nope. I cannot stand cold food—I won’t eat it 😂 and it doesn’t just have to be warm, I want my food hot. So what do I do instead?

1. If it’s soup or another food that has a decent amount of liquid in it (whether it be a sauce or broth), I reheat it on the stove on medium to low heat. I have a ceramic pan that is solely used for reheating food. This method works great: it heats food evenly and is relatively fast compared to the oven.

2. If it’s a casserole type meal (that doesn’t have a ton of liquid in it) or something like our favorite sausage muffins, I put them in a glass dish, cover it will foil (so that the top doesn’t get dark) and reheat it in the oven or in my Instant Pot Oven. This can take a lot longer, but I appreciate that it often tastes like it was cooked fresh.

3. For drinks like coffee, I either reheat it in a small saucepan on the stove or I use my Ember mug.

4. Outside of frozen vegetables, I don’t buy microwavable food/T.V. dinners. If I buy frozen veggies (or any veggies) that come in one of those plastic bags that are supposedly “microwave safe,” I either steam them on the stovetop or dump them onto a sheet pan and roast them like I would any fresh veggie. (I highly advise against ever microwaving food in plastic, and this research agrees.)

But What About Life in an Office Everyday?

If you go to an office job everyday and are now wondering what the heck you should do to reheat your lunch, let me offer a few suggestions:

1. Two of my former workplaces had convection ovens available to reheat food in addition to the microwaves, and one place even had a stove. Consider using those instead.

2. If your office doesn’t have a microwave-free option:

   1. Ask them to supply one because of your concern with the safety of microwaves. Send them some research, but ask with grace.

   2. Offer to buy one for the office if budget is a hinderance.

   3. If you have your own personal office, buy a small convection oven to use for yourself (although this might be considered a fire hazard, not sure!).

3. Pack fewer lunches that require reheating. Here are some ideas:

   1. An adult lunchable/charcuterie: cold meats, raw cheese, fruit, sourdough bread, and even a protein shake/smoothie on the side would be delicious.

   2. Homemade chicken salad on sourdough with a side of fruit, veggies, hummus, etc. I love this recipe.

   3. Wraps with all your favorite fixings.

   4. Cobb salads loaded up with all the protein (chicken, hard boiled eggs, etc.)

   5. Warm up your soups in the morning and store them in a stainless steel thermos.

This can be a controversial topic, so I’d love to know your own personal experience with microwaves. Do you use them? Do you have suspicions? Have you lived microwave-free for years and have some wisdom and ideas to pass down? Do you have a list of recipes you keep handy for office days that don’t require reheating? Please share them in the comments below!