In my list of Top 100 Hairy Chestnuts I Get Confronted With When I Talk About Cooking, “But aren’t microwaves bad?” comes in at about #25. I’m a fan of getting more people cooking, first and foremost. For some this involves using a microwave. Thus, my short answer to the above question is: If it gets you cooking with real food, go ahead, use a microwave. Indeed, I use a microwave from time to time. We have one at the office for heating our lunch, for instance. The longer answer, however, follows here…

Paleo Choc Muggin: a one-minute microwave meal
Julie Van Rosendaal’s 2-minute microwave mug brownie. I have a sugar-free Paleo Choc Muggin (a muffin in a mug!) version, available from I Quit Sugar For Life

Microwaves don’t radiate you

Microwave ovens use radio/microwaves to make the water molecules in food vibrate, which produces friction, which heats the food. It uses a form of non-ionizing radiation (it can’t directly break up atoms or molecules). This means it can’t damage your DNA like, say, X-rays do.

But they do emit EMFs

Building biologist Nicole Bijlsma says: Microwaves do emit EMFs three types of electromagnetic fields: electric field (minimal), magnetic field (can be high from the digital clock and also where the transformer is located) and radio/microwaves. The electric and magnetic field (from the digital clock) will be present even when the microwave oven is not heating. The magnetic field will increase when the microwave oven is in use and will drop off to background levels within one metre. The World Health Organisation has classified radio/microwaves and magnetic fields in 2011 and 2002 respectively as “possibly carcinogenic to humans”. However, unlike the pulsing nature of the radio/microwaves used in the telecommunications industry (mobile phones and Wi-Fi), the microwave oven uses continuous wave fields so the biological effects are not likely to be as bad.

Do microwaves kill nutrients?

Any cooking will change the nutrients in food in some way. Low and slow cooking preserves the most nutrients, as I’ve shared before. The faster you cook (or heat) your food, the more nutrients and enzymes you destroy.

A study published in The Journal of the Science of Food and Agriculture found that the amount of nutrients lost depends on the duration and way in which the food is cooked – steaming broccoli in the microwave for 90 seconds is better than zapping it for 4-5 minutes.

Research from the University of Oslo found that microwaving carrots, spinach, mushrooms, asparagus, cabbage, green and red capsicums and tomatoes led to an increase in the antioxidant content of the foods (in that the antioxidants become more available for absorption).

Some sources also claim microwave ovens can cause issues because:

  • They can heat food beyond their natural boiling point, thus scalding it.
  • They can leave cold spots from uneven heating, causing bacterial growth.
  • Overheating dairy can destabilise proteins

I tend to take these claims with a grain of …salt…or something. I think any kind of cooking can cause these issues if you’re hasty or lazy.

How to use microwaves safely

* Stand back. Because the radiation diminishes quickly over distance, standing further away from the microwave during operation cuts your exposure even more significantly. One metre is about right. And keep your distance even when the microwave isn’t in operation.

* Don’t put plastic in your microwave. All plastics leech chemicals (hormone disrupting chemicals such as phthalates and BPA, benzene, acrylamide) and/or metals (such as antimony, if PETE or number 1 plastics are used) into the food the hotter they become. Says, Nicole, “When the Milwaukee Journal Sentinel tested plastics labeled “microwave-safe” and advertised for infants, they were found to release “toxic doses” of Bisphenol A. The amounts detected were at levels that scientists have found cause neurological and developmental damage in laboratory animals.”

* Use glass or ceramics instead.

* Keep the microwave clean, especially around the seal.

* Don’t be hasty and lazy. Cook food low and slow.

The upshot, I ‘spose, is this: as with everything in life we have to weight up costs and benefits. Me, personally, I use other methods of cooking when I can (in part because I prefer to be able to see and smell and touch food as it cooks, to keep an eye on it). When I can’t, a microwave is fine, but I take the precautions (I always stand back, cook in ceramic etc.). No big deal.

We can get a bit too worked up about these kind of “hot topics”, but then forgot bigger and dirtier pictures. Like, who really knows how the food at their local cafe is cooked? Which oils? How much sugar? Who really  gets fired up about how their banana bread is made? I’d be far more concerned about these factors than the small impacts of microwave cooking.

Do you agree?

Have your say, leave a comment.

  • Lucy Travers

    Not sure if it’s just me, but I almost feel like microwaves are redundant. I have one however perhaps only use it once a quarter, mainly to reheat leftovers from the night before if I don’t have time to heat them in the oven. I could happily go without one all together.

    • Totally the same Lucy. I would like to get rid of it permenantly, but Husband thinks it is too convienient for reheating left overs. Next time we move house, though, it won’t come with us. Or if it dies, we won’t replace it.

      • Last resort in our place as well.. Like you Sarah my husband tends to use it the most for reheating. Warming drawer makes everything dry!

  • I have not had a microwave for nearly three years and I can honestly say I have never missed it. More space in the kitchen for my new juicer 🙂

    • Debs

      me too. They are so unnecessary

  • Rosie

    Thanks for the info Sarah. I sometimes use a microwave at work to reheat my lunches or sometimes at home I’ll cook veg in it. I do prefer other options but for me it’s handy. It’s also handy for my dad. He uses his quite a bit. But then again he lives on his own and is nearing 91. I would much rather he use the microwave than his oven or even his stove. Being a bit older I think its safer for him he doesn’t have to remember to switch it off.

  • Lola

    Thanks for the info, Sarah. I’ve been leery about microwaves for years, and you’ve pretty much confirmed what I already knew. Think I might continue to leave the microwave for crap-the-kettle/stove-isn’t-working emergencies!

    P.S. I might be wrong, but I think microwaves ’emit’ EMFs, not ‘omit’ them, and plastics ‘leach’ chemicals, not ‘leech’ them…?

  • Anna Sheppard

    Thank you for a concise explanation. I only wish the study comparing microwaving broccoli stated how long each method was used for – e.g. 1 minute in the microwave? Or were most nutrients lost after blitzing for several minutes (i.e. overcooking it anyway.)

  • I got rid of my ‘science oven’ a few months ago and am much happier without it, but that is probably due to having more available bench space! I definitely don’t miss it when it comes to cooking though!!

  • Cristie

    I like to use the example of boiling an egg; if you boil it in water in a saucepan on the stove what does it do? It cooks and stays in it’s shell.
    If you do that by putting an egg (in it’s shell) in the microwave, it explodes.

    • Sara

      I always wondered why it did that – what do you extrapolate from that?

    • Barbara

      If you boil an egg in water it actually will sometimes crack the shell, if the egg was from a fridge and you heat the water too fast. The inside, being liquid, expands faster than the outer, brittle shell. But if you warm it up gently it won’t. Similarly If you heat your egg in a microwave slowly enough, it won’t explode. In fact a friend of mine cooked his eggs in the ‘wave all the time.

      • alien

        Poach eggs work well in the microwave just prick the yolk. 40 secs

  • Becki

    we have one mainly used by my elderly father to reheat tea and coffee as he drinks it slowly / forgets it

    • August

      I do this all the time too!

  • Bec

    When my partner and I were in Germany last year we stayed with really varied types of people-a couple, a large extended family (two parents, grown adult kids as well as a couple small kids + lots of entertaining) a young family, and an older family who lived with ther grandparents. One thing ALL of these people from the couple to the large extended family had in common is that NONE of them had a microwave! Coming from Australia I found it a really notable difference in cultures-however we never once missed the microwave in the whole time we were there.

    • Bec

      *their Grandparents.

    • Rosie

      Yes and did you also happen to notice that someone is almost always home and cooking? Some may be able to share thesr chores but like I noticed with my italian relatives in Italy was that no sooner do the finish breakfast when they are organising and preparing for lunch and then the same again with dinner. Perhaps if it’s a one or two person household you wouldn’t have to cook so much.

  • Danielle

    This is an excellent point “If it gets you cooking with real food, go ahead, use a microwave.” and what I recommend, as well!

  • Rebecca

    Hi Sarah, I don’t have a microwave – I just don’t need it. Even for reheating, how long does it take to throw a pan on the stove and stir? Also, to me, leftovers taste better cooked on the stove. What I find fascinating is that nobody seems willing to eat leftovers cold now that there are microwaves. If I can’t be bothered reheating leftover food, I just eat it as it is. There’s nothing wrong with cold cooked leftovers every now and then! PS Your comment about microwaves & cafes is right on the money …

  • niki

    I try not to use my microwave but cave whenever I need to defrost a couple of sausages for a super fast dinner. This post got me thinking though – are things like FitBit and other GPS devices that track your calories and running distance etc (wearable tech) bad for you? One item I was looking at clips onto your bra and I chickened out having a gadget so close to my heart. Am I overreacting?

    • Cassie Hower

      Have you tried filling the sink with some hot water and putting your sausages in it to defrost? In a sealed plastic bag so water doesn’t get to the meat. This actually works quite well. Then just cook them a bit slower than you normally would in case they’re still a little frozen in the middle. You could do this with any meat. Just make sure to cook it soon after. The positive here is you don’t get any cooked bits like you may in the microwave.

      • niki

        No I haven’t tried this but I will! Thanks Cassie. 🙂

      • feliss

        This makes me laugh because it sounds like such a novel idea to us but it’s what my mum used to do when I was a little girl (I’m 49). Plus ca change ….

    • alien

      Love it for defrosting very handy

  • Sara

    Thanks for this logical, evidence based and rational post Sarah. I love cooking but frankly have never mastered ‘microwave’ cooking simply because it does not allow me to tinker which is how I’m used to cooking. But I do use one for reheating, cooking my dogs food sometimes and the occasional water reheating. While I wouldn’t be devastated if I no longer had it I think getting hysterical over microwave use is probably more detrimental than…using a microwave. Balance is the key.

    I have a friend who is so panicked about getting cancer that she is in a contestant state of stress. Did that sunscreen give her cancer? How about those 4 times in her life she had a spray tan? That microwaved gluten free muffin? Did walking past that construction site with dust give her cancer? Was swimming in that overly chlorinated pool a risk? And on and on and on. She often asks me about beauty products and if they’ll give her cancer. My belief is that unless there’s good evidence for a product being unsafe, worrying about what’ll give her cancer is more likely to give her cancer than the stuff she worries about giving her cancer, particularly as she is such a cautious consumer anyway. I’m all for educating yourself but when it becomes obsessive I think it’s actually doing more damage than good.

    It’s great to see your sensible approach to something that I find a lot of people get disproportionately worried about.

  • Kathryn

    The issues with microwaves are not just the health implications and what it does to food but also the environmental impact. Appliances like microwaves are designed to only last a certain amount of time and disposing of all these unnecessary appliances has become a massive environmental issue. Using a microwave is a complete contradiction to cooking “low and slow” when all homes have ovens and stoves. I haven’t had a microwave for almost 10 years and like Philippa have honestly never missed it.

  • A logical and balanced approach. Microwave use is better than not cooking, but getting into the habit of easy stovetop or other cooking methods will long term be better.

  • Amelia Hill

    100% disagree, Sarah.
    I’ve been confined to ONE ROOM for 5 years due to severe Environmantal Illness/Multiple Chemical Sensitivity, ElectroHyperSensitivity & Chronic Fatigue.
    I’ve read plenty of research but the most convincing evidence anyone needs is personal firsthand experience – & that, I have a HEAP of.
    Walk a day in the shoes of someone living with MCS or EHS (Electrical Sensitivity and you will know the truth.
    The things that make me (& all the others like me) the MOST ill? microwaves, wireless Internet, cordless landline phones or baby monitors, Smartmeters.

    I share my story on social media & tv/news/online interviews to raise awareness – happy to forward deets if you are interested in learning more. ??

    • TeTe

      I would have to suggest Amelia, that Sarah’s advice isn’t for everyone. i think she would be the first to admit, if anything is an issue for your personally, then stick to your own instincts and medical advice (from wherever you choose to source it). Most people don’t suffer from MCS or EHS and therefore Sarah’s advice could quite sound for them.
      Just like when her recipes list an ingredient you might be allergic too, she’s not saying you should eat it regardless.
      I think we’re all adult enough to know when to listen and when to judge for ourselves.

  • Chickstar

    The Tupperware Microsteamer actually uses the microwaves to heat and boil water in the base which in turn steams your food rather than microwaves your food! (The microwaves are bounced off the other components and directed into the water due to metal enclosed in the design of the lid and steamer shelves) Microwaves are also very energy efficient and use much less electricity than a conventional oven…my microwave would have to be over 15 years old and still going strong! Oh and by the way, Tupperware is BPA free..

  • Nik

    With you 110% – I use my microwave about 5% of the time to cook. Good glass or pyrex dishes are available from any supermarket. Thanks, as always, for laying out the facts in an easy-to-read digestible and practical.

  • Angela

    I don’t have microwave…you don’t need it! Plus I can use the space for my thermomix!

    • alien

      I have both!

  • i’d be more concerned about holding a mobile phone to your head all day or sitting with a laptop on your legs.

  • Erin

    I still have a microwave but have replaced the space it used to be with a dehydrator. The microwave had been delegated to the junk room and only gets used when I need to warm up a heat pack. I have never felt comfortable using a microwave for anything other than reheating, it just doesn’t seem natural to cook food in it.. Stove top or oven now does the trick for any reheating- yes, it is a little more time consuming but it makes me feel better!!

  • Mel

    This is an irresponsible article that has been skewed to falsify the effects of microwaving food. Even the University or Olso study you refer to (obviously gleaned from another blog) speaks about the nutrient increase of some vegetables in microvawes but we all know this to be true of stovetop steaming of said vegetables. Microwaves kill nutrients, and simply encourage people to ‘cook’ their pre-prepared bought food… Saying people should use a microwave because at least they are cooking or in the kitchen is like saying they should drink cordial just so they can get the water…

  • Maria

    I have never owned one. I grab a saucepan to reheat and made all baby food from scratch. Just the thought of the whole process of microwaves (even the name) scare me…

  • Evie

    Yes, I agree with your sensible advice. I know some people who are quite hysterical about ‘evil’ microwaves. We use ours for some things because they are quick and easy.

  • I have been wondering about this for a VERY LONG TIME! Thanks for clearing this up. Good to know they are not quite as bad as many say they are. I guess a large part of the issue is what we put in them…so if we are using frozen, packaged food alot then this is not good for our health, however if we’re simply heating up ‘healthy’ leftovers then not such an issue.
    Zoe B