The UA forum has some recent threads on cancelled flights within a MR, including this one, so the airline FFP forums might be a better starting point for program specific information such as compensation or help as an elite with IROPS.

As to the food recommendation, I've stuck a handful of granola bars in my carry on as my go-to food as they're individually sealed & wrapped, provide some healthy energy and even if squished and broken are still edible if slightly messier.