The Microwave of Death !?!?

August 7, 2008 4:04 PM

Is cooking (or re-heating) my food with a microwave destroying the food, sucking out nutrients that would not be removed by heating on the stove top in a stainless pan? I've heard this here and there, dated an Earth Mother South Austin Woman who was/likely is certain that I may as well put nuclear waste products AND rat poison in my food, pretty much heard the same about twenty minutes ago from a woman working in the vitamin/supplements department at Whole Foods, yet another Austin Earth Mother type; just the fact that I said the word 'microwave' caused her to get a big frowny face, looked like she had gas or something. Meanwhile, back at the ranch, I like to toss broccoli with just a shade of water into the microwave for a couple of minutes, or re-heat my rice and beans or soup or whatever. Related: Does cooking vegetables in a pressure cooker rob them of needed nutrients?

I just Googled and found widely varying opinions, and all of them certain of their validity: Either "Microwaves Are Death !!!" (insert heavy, unhappy music here, music that starts on its own upon opening the page) or "Hey, what the heck, those folks are nuts; microwave cooking is the best thing since sliced bread."

So I'm coming here to get the bottom line.

If you are of the "Microwaves Are Death" community, do you now or have you ever owned Birkenstock sandals, or were you considering purchasing some this afternoon?

If you are of the "Microwaves Are Just Swell" camp, are you smoking a cigarette as you read this, and/or maybe sucking down a MacDonalds Quadruple Bacon Burger of Death supersized with fries and a diet coke?

All kidding aside, I trust this community. Give me the news, gang.

Thanx!

posted by dancestoblue to food & drink (26 comments total)

All microwaves do is move the molecules in your food around (i.e. "heat"). Just roll your eyes at the hippies and continue to heat your food in the way that makes it taste best to you.
posted by Aquaman at 4:10 PM on August 7, 2008

Cooking is cooking. Having said that, I like my veggies steamed, but I also have no qualms about nuking a potato.
posted by konolia at 4:11 PM on August 7, 2008

Yep. Microwaves use NON IONIZING radiation to add energy to polar molecules (mostly water) thus also heats them up. Those molecules then transfer heat and enegry to other molecules and heat them up. Every other cooking technique uses some other method to transfer energy from the cooker to your food.

If vitamin/molecule/substance/whatever is degraded by heat then it will be degraded by microwaves and by any other source of heat. Over microwaving it will do as much damage (though maybe faster) than over baking it. Really it's all about heat delivery and desired texture. Microwaves can't make some food crispy, and boiling some foods may be faster than baking, but nutrients will leech out into the water.

It's all preference.
posted by Science! at 4:19 PM on August 7, 2008 [2 favorites has favorites]

or heat/energy or however specific you want to get for all that.

Microwaves make stuff hot. Just like any other method.
posted by Science! at 4:20 PM on August 7, 2008

Some people choose not to understand science.
posted by gjc at 4:22 PM on August 7, 2008 [2 favorites has favorites]

Oh, and FYI I'm drinking a high life, watching old school Family Guy, and have pizza rolls in the oven. Non of that matters because my actions and preferences have absolutely no impact on the laws of physics and by derivation the laws of biology.
posted by Science! at 4:23 PM on August 7, 2008 [5 favorites has favorites]

Cooking vegetables in water leaches some nutrients, no matter how you choose to do it. If you're going to cook vegies in the microwave, just cook hem in a covered glass vessel without water.
posted by oneirodynia at 4:27 PM on August 7, 2008

It is true that cooking vegetables can reduce their nutrients. Broccoli, for instance, loses the vast majority of its nutrients when boiled, so it's best to steam it lightly if you want to cook it. (Well, at least I read that once. But then I read this and now I'm totally confused.) I don't know for sure, but I think that's probably more a result of its contact with the hot water than with the fact that it's being heated. Maybe heating breaks down some nutrients on its own, but if it does, then that's not going to be any worse in a microwave, which just heats using a different method. In fact, since your broccoli (or whatever) isn't coming into contact with steam that can osmose the nutrients out of it, it would seem to be a better heating method.
posted by Dasein at 4:27 PM on August 7, 2008

Specifically, microwaves excite water molecules within food to heat them up so the food essentially cooks itself. We're talking about physics here.

I don't trust sources--especially those hystperical hippie mom types--who don't have the basic scientific understanding behind how things work. That said, a good trick in weeding out online crap (because there's a lot of crap out there) is to start a Google search at only EDU domains (site:.edu). Hell, if you're scientifically inclined and have taken collegiate biology/physics courses, you can weed through actual scholarly articles from Google Scholar.

If you check Wikipedia for information, always view the cited sources; the same idea holds for Snopes. For example, another item of interest is the use of microwaves on food in plastic containers.

Or that microwaved water kills plants OMG!!

Now. I wouldn't stand in front of a microwave and stare at it while it cooks something for five minutes, mind.

As others have said, cooking in water can certainly leech out nutrients from food, but this is hardly limited to microwaving. And cooking also makes other nutrients more available and easily digested by the human body. I wouldn't worry about it so much.
posted by Ky at 4:34 PM on August 7, 2008 [1 favorite has favorites]

This page from Ask A Scientist has a bunch of PhD's answering the question. Microwaves do destroy enzymes because heat above 50 deg C destroys enzymes and microwaves make things hot. But it's not really any different from boiling or frying.
posted by GuyZero at 4:36 PM on August 7, 2008

Oh, and while I'm in the "nukers are fine" camp, I don't smoke or drink or eat fast food. But I do have a science degree (unused, slightly old and wrinkled, possibly with coffee stains). ;)

In this recent mainstream article, nuking preserves a lot more vitamin C than boiling or frying, for example. It's a decent read--but not something that some people like myself didn't know from several years ago.

Things should balance out among cooking type, raw/cooked, food types, and whatnot. Big picture.
posted by Ky at 5:04 PM on August 7, 2008 [1 favorite has favorites]

Well, I'll tell you this: regardless of whether or not your Austin Earth Mother is right, microwaved broccoli is better for you than a pre-cooked microwavable cheeseburger, so the point's more or less moot.
posted by ten pounds of inedita at 6:05 PM on August 7, 2008

Microwaves are fine. I have a Ph.D. in biochemistry and I'm eating pasta with zucchini and garlic breadcrumbs. So there.

Now to the actual answer part: microwaves have been covered pretty well but regarding pressure cookers, they can destroy more nutrients than other cooking methods (other factors being equal) because they allow food to get hotter. Heat can destroy vitamins, and the higher the temperature, the faster the degradation. Water heated in an open pan or microwave will only reach its boiling point, with a few extra degrees thrown in for boiling point elevation due to other stuff in solution.

Water in a pressure cooker is kept under pressure precisely so it will reach a higher temperature before boiling (so food cooks faster and gets softer). Food gets hotter in a pressure cooker and, if left at high temperature for too long, you can lose vitamins due to thermal degradation. I still cook certain things in a pressure cooker because they take too freakin' long (chickpeas) or stay tough forever (goat meat) at one atmosphere, but it's not my preferred method of cooking. I don't worry at all about heating stuff in a microwave, though.
posted by Quietgal at 6:12 PM on August 7, 2008

I read something from Dr Andrew Weil recently (checked it out of the library, so I can't remember which book exactly, maybe this one). He said that microwaving itself was fine, BUT DON'T use plastic containers, plastic wrappers, plastic bags, etc. Only glass and ceramics. He is concerned that plastics in the microwave may leach chemicals into your food, but otherwise microwaving is fine.
posted by marsha56 at 6:18 PM on August 7, 2008 [1 favorite has favorites]

Conventional cooking has its downside too. When you toast bread or roast meat, the process you're using to make these things taste good is called the Maillard reaction. Essentially sugars + amino acids = tasty stuff. However, some Maillard reaction products are carcinogenic, which isn't so good. (This isn't a big deal, but they probably do increase risk of cancers of the digestive system very slightly).

But as everyone knows, you can't toast bread in the microwave. Due to the lack of dry heat and the shorter cooking times, microwaves don't cause the Maillard reaction to happen nearly so much as conventional ovens do. This is why some things are less tasty when cooked in the microwave and why things specifically intended to be microwaved tend to be filled with salt and chemicals - microwaves cause less flavour to be developed in certain foods. But it also means that the carcinogenic byproducts of the Maillard reaction don't get created.

This means that (some) foods cooked conventionally will have more carcinogens present than foods cooked in the microwave. Like I said, it's not something to worry about, but it's definitely a handy fact to know when dealing with people who claim microwaves are unhealthy.
posted by xchmp at 6:44 PM on August 7, 2008

Hey, what the heck, those folks are nuts; microwave cooking is the best thing since sliced bread.

No, I don't wear Birkenstocks, but I do drive a Prius.
posted by mmoncur at 7:28 PM on August 7, 2008

Now. I wouldn't stand in front of a microwave and stare at it while it cooks something for five minutes, mind.

They're shielded, don't worry. Also, you'd probably notice yourself getting warm if they weren't, and you could just step back.
posted by you're a kitty! at 9:01 PM on August 7, 2008

I stand in front of the microwave and watch it cooking for minutes at a time sometimes, my hair hasn't started falling out yet. And I've never noticed any sensation of getting warm, either.
posted by jacalata at 9:54 PM on August 7, 2008

Another common story/myth that I've heard is that you should always leave microwaved food for a few minutes after removing it from the oven, because the molecules will re-emit microwave radiation and (OMG!) cook your insides. I've even heard this rumour from friends who work in the sciences.

The truth of it appears to be that it's common sense to allow a minute or two for the heat to distribute itself more evenly in the food, thus avoiding searing hot-spots - although stirring probably does the job just as well. Technically (correct me if you physics is rusty) it's possible for a water molecule to absorb then re-emit radiation at the same frequency, but this would happen pretty much instantly and wouldn't continue after the over is turned off. Once the over is off = no more microwaves, just heat.
posted by le morte de bea arthur at 2:38 AM on August 8, 2008 [1 favorite has favorites]

Terrible, terrible lack of proofreading. I'm so ashamed.
posted by le morte de bea arthur at 5:37 AM on August 8, 2008

I have to admit I have cooked things like broccoli and potatoes in the microwave, but a steamer is better IMHO. Doesn't need to be one of the appliance ones, the stainless 'widgets' which go over a pot of water work fine, heck, even a pie crust tin with holes poked in it works as well. Both require an appropriately-sized pot with a lid.

The thing I love about steaming is cooking time is less essential, and it's basically one-pot, just toss in the broccoli, chopped-up potato, fish or something else steam-able, at reasonable intervals, and voila, dinner. Without the hassle of keeping much of an eye on it. It's not going to burn, and the steam keeps it from drying-out. Probably wouldn't work too well for families, but for singles, or possibly couples, it's just fine.

I've gotten wary of the microwave since it interferes with my wireless network completely (open concept apartment), there's definitely some sort of emissions being radiated by it.
posted by hungrysquirrels at 6:04 AM on August 8, 2008

They're shielded, don't worry. Also, you'd probably notice yourself getting warm if they weren't, and you could just step back.

Oh, I'm sure this is true. I didn't mention that my parents still have and are using an early generation microwave from the mid-'70s. That thing does make me nervous, which could be silly, but I remember my mom yelling at us all the time to get away from it. Perhaps it's a learned behavior on my part.

I'm not terribly worried about the newer models, though. :)

If there's one thing solid about the American economic model, it's that consumers do have recourse if particularly unsafe things are making it to market.
posted by Ky at 6:55 AM on August 8, 2008

Re: Microwaving in plastic fears--

Yes, this is a popular one for people to be freaked out by (excuse the terrible grammar). I had linked the Snopes article about the cancer scare that marsha56 talks about up there, but I'll cite the original source for people who didn't bother to read it and other sources and just favorited the warning out of instinct:

Johns Hopkins Bloomberg School of Public Health:

Email Hoax Regarding Freezing Water Bottles and Microwave Cooking

The Internet is flooded with messages warning against freezing water in plastic bottles or cooking with plastics in the microwave oven. These messages, frequently titled “Johns Hopkins Cancer News” or “Johns Hopkins Cancer Update,” are falsely attributed to Johns Hopkins and we do not endorse their content.

Freezing water does not cause the release of chemicals from plastic bottles.

In general, it is best to follow the manufacturer’s recommendations when using any plastic products. When cooking with plastics, only use those plastic containers, wraps, bags and utensils for their intended purposes.

The U.S. Department of Agriculture Food Safety Inspection Service (FSIS) has some helpful guidelines for cooking with plastics in microwave ovens.


Other sources about cancer-inducing plastics in microwaves:
No Link Between Microwave Cooking and Cancer, Expert Says

Does the Plastic in Water Bottles and Plastic Wrap Cause Cancer?

Microwave Myths

Harvard Medical School: Microwaving food in plastic: Dangerous or not?

So the bottom line is: Plastics tested by the FDA and labeled "safe for microwave" are thus. It's not like you can just put anything into the microwave, but I assume most of us knew that.

Exact Google search terms: dioxin plastic microwave oven site:.edu -.pdf -waste -doc
posted by Ky at 7:15 AM on August 8, 2008

I microwave stuff pretty much every day, especially my lunch at work, just so you know that I'm not really an "OMG death rays!" person. But I do totally notice that food cooked in a microwave just does not give me the same feeling of having eaten something wholesome that I get when eating the same food cooked by traditional methods. I'm not talking about frozen entrees, either--I mean things like steamed broccoli. I don't purport to know anything about the science of microwaves. All I know is how I feel. I think a lot of people have this same perception, and that is probably what gives rise to the widespread notion that microwaving is not as healthful as stovetop/oven cooking.
posted by HotToddy at 8:10 AM on August 8, 2008 [1 favorite has favorites]

...food cooked in a microwave just does not give me the same feeling of having eaten something wholesome...

Could it conceivably be that you mentally associate speed and convenience with 'bad' food? And likewise, could you be associating traditional methods of food preparation with 'wholesomeness'?

I demand a blind taste test! But not broccoli please.
posted by le morte de bea arthur at 9:07 AM on August 8, 2008

Could be. I'm willing to eat any meal you pay for and report back on my feeling of having eaten something wholesome!
posted by HotToddy at 3:02 PM on August 14, 2008