Losing--and not in the happy sense.

If your work offers a meal plan, I think it's completely reasonable for you to work within that rather than taking the time/energy of packing. Portion control and making good choices are the major obstacles that you outlined, so work on tackling those! You could make a rule that you only have dessert on Wednesdays or odd numbered days or something--it sounds like "never" is not reasonable, so work with what you can stick to. A portion control option might be to have a small container (like a half cup sized) that you can put anything in you want at a meal -- anything! bread! mac and cheese! cake! -- but the rest of the meal has to be veggies or salad or lean protein, etc. so you always get a treat, but you don't ruin the meal. You're on the right track to focus on calories now, you just need to build good habits until they become second nature. :)