Use the microwave. Working in an office all day isn't paleo either!

I'm not as concerned about microwaving, in general, as I am with the CONTAINER I use. Plastics, even deemed "microwave-safe", will leach nasties into your food (BPA, et al). Paper bowls will contribute a nice amount of tasty (GACK) chemical wax, as well.

I keep a microwave-safe stoneware (or glass) bowl/plate at work in which to nuke my grok noms. No more than 3-4 minutes total heating time, and resting period of 1 minute to allow the vibrating water molecules to relax.

A small toaster oven may work for you. Not as fast as a microwave, but it would get the job done.

eat it cold! i almost NEVER reheat my leftovers...for some reason i prefer them cold!

1) Get a portable grilling machine like George Foreman's - a small one that will fit on the counter top. All that needs to be done is whack on your meat (stored raw in the fridge). I also do vegetables like onions and tomatoes on it. Do not discard the fat that gets caught in the tray, pour it back on top of the meat. Pile some salad on the side and voila, paleo lunch.

The only problem I can see with this is that you will get complaints about the smell of the grilling from other workers/the boss (especially if you do not have an office kitchen?) Unless you are the boss, I suggest treating everyone to a grill and/or let co-workers use it too (they can make toasted sandwiches on it) and then you will be facing a win/win situation.

2) If grilling is completely out of the question then a small slow cooker/crock pot would be perfect. Put your (lightly cooked) meat in it in the morning and by lunch time it will have heated thoroughly and evenly and produced a glorious rich sauce. You can get very small crock pots that only need to be plugged in - easy.

Again, you may get complaints about the smell, but if you can position it in the office kitchen, then all should be good come lunch time.

Build a fire outside......sorry couldn't resist. I often bring things that I can eat cold. Leftover steak on salad is pretty good stuff!

You might consider a thermal cooker. They are like a thermos with a pot inside. You heat everything up in the pot and then put the pot in the thermos for long slow cooking. I have not tried it but it is number two on my list of cooking experiments to undertake and the one I think would be most handy for the office.

Depending on what you are eating, certain foods can be put in a container which rests in a bowl of very hot water. I've done this in places where there are no microwaves. Works best on liquids or semi-liquids. Or for meat, you could put in a plastic bag and put in the hot water.

I use the microwave.

I would just fast. I find it much easier to skip lunch than when I used to bring it. saves me some time, and certainly effort. Sorry, not exactly the answer you were looking for!

Why is it unacceptable to keep a toaster oven at work and use glass dishes so you can reheat in them directly? That is what I use. Pyrex dishes with lids and a toaster oven. Why the heck do you need anything like a rice cooker etc.?!?!? Microwaves are not safe, I know folks think the radiation issue is debateable, but I am sure that even if it is not putting radiation into the food, it is killing the nutrients in the food. No point in making my food DEAD AS ALL HECK killing all the beneficial nutrients.

I stay far, far away from microwaves and bring foods I like at room temp to the office. I much prefer cold leftovers to nuked food.

Wouldn't a steamer be perfect? You wouldn't even have to think about cooking, just throw anything in there...

We have a small kitchen with a 2 burner hotplate. I keep a small skillet for rewarming.

was looking for an answer myself!

found this, seems like a brillant idea!!

http://www.chipchick.com/2009/04/usb_lunch_box_warmer_heat_food-2.html

im going to buy it and see how we go. You can get them off ebay or some online shops if you look around.

My experience with being a picky human being and using a microwave is that the whole process ends up being: "heat until some of it is burning hot and I have to use the tablecloth that hasn't seen the world outside of the drawer since the 70's to pull the scorching glass container out of the microwave and throw it dramatically onto the closest non-meltable surface, where I then stir it until the freezing cold semi-frozen parts combine to create a generally luke-warm meal".

My solutions:

1) Really good double-walled stainless steel Thermos (the brand). While heating my leftovers, I pour leftover boiled water from the kettle into the Thermos and seal it off for 10 mn or so, so that when I put my leftovers into the Thermos it is already smoking hot inside. This is the key to maintaining a hot temperature! For a semi-warm lunch I like to fill the Thermos with very hot bone broth, then pour it over julienned raw veg and leftover meat- warm and lovely, but fresh and crunchy all at once.

2) Toaster oven. When you think you may be hungry in 20 minutes, put your glass container in the toaster oven and set the temp. Make sure you bring an oven mit or some kind of hand-protection (that old table cloth comes in handy yet again!) so that you don't have to try and use your fork to pull your container onto an officemates plate who may or may not be unimpressed if you chip it during the process.

Don't do what I do.

I stick it in the incubator in my laboratory...

Granted there's no live stuff in the incubator, we use it as a "dry" area for clean glassware.

Ghetto-none the less.

About an hour before I dig in, I put it on a heat block under the hood.

Don't do this, boys and girls.

You could just leave it at room temp for a few hours and then eat it. I yank mine out of the fridge in the morning and put it in a small cooler alongside one bottle of frozen water. The frozen water keeps the cooler moderately cool inside but not super cool. Most food I bring tastes fine at that temp. I only use the micro once in a while for certain foods that I really like hot. But I think most foods taste better at room temp than partially recooked/heated in the micro.

I've made poached/over easy eggs at work with boiling water before...you have to keep pouring the boiling water on and then let steam...repeat. I assume you could do the same with your meat and veggies.

Seriously, just get a good thermos. I pack soup/pot roast/etc at 6am, and it's still hot at 5pm

I think one of those hot pots (that heat water to boiling) would work if you put your food in a boilable vacuum packed bag. However unless your office allows you to cook over a campfire - you have to use something that has technology involved :-). Draw backs of this method, plastic bags.

my food (usually chunks of corned beef) goes from the fridge in the morning to my bag, and stays there until lunch. I know the "safe temperature" is colder than 4oC, or hotter than60oC, but I have a gut of steel, and i've never given my self an upset stomach, plus it's just the right temperature imo.

I have been looking for a microwave alternative and came across this:

http://www.amazon.com/gp/product/B006H5V7ZY/ref=s9_wish_gw_d7_g79_ir01?ie=UTF8&colid=2MB00J5VYLAYL&coliid=I10XCW4RU50BNG&pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=1C55T769DNMZQKKRVS43&pf_rd_t=101&pf_rd_p=1389517282&pf_rd_i=507846

Have not tried it yet but looks promising.