Help me not go to Mars and get more candy bars

Maybe you could order a http://www.peapod.com delivery to your hotel? McCormick Place is sort of in a dead zone, amenities-wise.

You are staying very close to Chinatown. There will be tons of Chinese restaurants and markets, but that doesn't help you much if you're avoiding factory-farmed animal products. There's a Trader Joe's a mile and a half from the hotel at Roosevelt & Wabash. Grabbing a cab is trivial: if the light on the roof is lit up, the driver is looking for a fare. Just put your hand up and make eye contact when a cab comes by. Or let the hotel hail one for you. Program a cab company's number in your phone contacts and you can call one from anywhere - I like Flash cab - (773) 561-4444 (no affiliation). For traveling, I really like those soup cups that you just add hot water to. You can get hot water on the plane, at the conference, from the coffeemaker in your hotel room... the McDougall's varieties are vegan (http://www.amazon.com/exec/obidos/ASIN/B000FFIEL2/metafilter-20/ref=nosim/) and you could even have Amazon deliver them straight to the hotel for you. There are tons of instant oatmeal cups, too, for breakfast - not sure if this will result in a carb crash.

This doesn't directly address your request, so forgive me if this is unwelcome advice, but the image of you coming to Chicago and spending your entire time at a conference center and its attached hotel, gnawing on granola bars, is a little heartbreaking. Chicago's a fantastic restaurant town and your dietary restrictions aren't hard to accomodate here. Here's a http://www.yelp.com/search?cflt=vegetarian&find_loc=Chicago%2C+IL%2C+USA to get you started. (My two cents: I've heard great things about Mana; skip Handlebar). These really don't have to be expensive meals. In Chicago, you can use the https://www.uber.com/ app to request a cab at their regular rates. It works great, and the fee and tip is included in the service fee that's charged to your card, so there's no awkwardness at the end of your ride - just say thanks and leave. I don't love travelling for work myself, but getting out, trying some restaurants, and seeing the sights makes the whole experience a lot more worthwhile.

Call the hotel to see if you can get a mini-fridge in your room. Usually one can be provided at no charge. Mapquest says there's a Publix up the street, but that's not right (and how WEIRD is that?) When you arrive, get a cab to Whole Foods and check out some of their prepared foods, lunch meats, etc. I'd do line caught tuna over a salad that you can procure from the restaurant in the hotel. Breakfast can be nut butter on dense grain bread and a greek yogurt. They may have hard boiled eggs. You can make this work and it won't even be that hard.

Chicago is a great place in general to find restaurants that cater to specific needs and tastes. To add to the great advice above, talk to the hotel staff or conceirge and mention your needs, and ask about advice or directions.

Also, if you find a compelling restaurant that works for you, make an adventure of going there, and drag someone along.

I realize that your normal routine is to eat at home. But it sounds like much of that comes from living in a small town where restaurants have difficulty accommodating your dietary needs. There are soooooooo many places in Chicago that will be more than happy to accommodate you... wonderful places with wonderful food, many of them close to your hotel/convention. For example, while I understand that you eat cruelty-free eggs and fish, try a quick Google search for "vegan restaurants." There are dozens. http://www.karynsongreen.com/menu.htm is a beautiful place with terrific food that is a quick cab ride away from McCormick. It's adjacent to Greektown, too, so you might be able to talk co-workers into a group trip out that way. And, while they have their steaks and saganaki, you can drop in on Karyn's and meet them for drinks before or after. If you want to eat quietly in your room for social reasons or simply out of habit, there are good bits of advice in this thread. But if it's simply because you're not used to being able to find options that suit you... welcome to Chicago. We can help you here.

I don't have Chicago specific info, but many http://www.kindsnacks.com/ are good on protein, lower in carbs than nearly all energy bars (bonus: no maltitol!), and travel very well.

BTW, taking taxis in Chicago is easy, even without the Uber app (but that might make it easier). Your hotel will likely have a taxi stand at one of its doors, and/or doorman or porter who can get one for you. When you're heading back to the hotel, you can walk out to the curb and stick your arm out above your head when you see a cab 1/2 block away (or closer).