Prep food ahead of time if you can. Cured meats and things like biltong or pemmican will last without refrigeration. Boiled eggs are convenient too.

On the rare occasion I need to stop at a supermarket, I end up wondering around only to get pissed off at the lack of options where I can't cook something. Usually I'll get some cottage cheese and then fast until I have more options.

Working at an event at a hotel today, I stopped at my butchers this morning because hotel food sucks. I've eaten half a kg of biltong today.