Thanks all for great suggestions.
Overall, it went pretty well. I called the hotel to ask about the microwave but the answer was no.
Before checking into the hotel, I made a trip to a grocery store and got some essentials: rolled oats, almond milk, bananas, blueberries, apples, oranges, canned black beans, and salsa. I also brought with me a couple of small glass bows (with lids) and a can opener. I felt a bit awkward checking into a fancy resort with large Trader Joe's paper bags. But nobody noticed/mentioned it - so I guess sometimes we judge ourselves more than others do. This ("I don't want colleagues to make fun of it") had been my excuse for not eating well when traveling. Having done it once successfully, I feel more confident about repeating in future.
My meals:* Breakfast: overnight oats with bananas and berries. I could have gotten steel cut oatmeal from the hotel but making my own allowed me to skip the hotel buffet. I didn't want to get tempted by oily potatoes and sugary pastries.
* Lunch and dinner: I ordered plain steamed brown rice from the hotel and mixed it with the black beans and salsa. Tasted delicious. The first time I called to order the rice, the person on the other end asked me three times if I just wanted just plain rice. The delivery showed up to my room with a side of complementary fries! It was almost as if they wanted me to fall off the wagon so I don't order more special request foods. Needless to say, I sent the fries back and they got my order right for the rest of stay
* When I got hungry beyond these meals, I just snacked on apples and oranges.
I was able to eat like this for 95% of the stay (which is 95% better than what I am used to doing on such trips). The couple of times when I had minor slip-up were during my meetings/conference where the food was brought to the room and I reached for them without realizing what I was doing. But I was able to catch myself in the act and control the damage.
This trip allowed me to escape the deep freeze in Chicago and spend a few days in sunny Southern California. I tried to have a positive attitude about that rather than getting caught up in blaming work and travel for bad eating habits. This helped me tremendously so stay on track.