If I had to choose, I would probably give up coffee because I honestly never drink coffee anyway. I wouldn’t feel that afflicted and could try and make teas with herbs I find on the battlefield as a substitute for a warm drink.
What I found to be fascinating about a Civil War soldier’s diet was their drastic desperation and dependence on coffee. From what I’ve read in the given articles, coffee seemed like the one part of these soldiers’ lives that kept them motivated to make it through another day of the war. It makes me wonder what the morale of the Union soldiers would have been if coffee had been just as scarce up north as it was in the south. It also makes me wonder whether coffee reminded them of their lives back home where they would have their wives or daughters to cook for them.
This also makes me wonder how almost none of the soldiers had any knowledge of how to cook anything while enrolled in the army. The thought of not knowing the basics on how to cook baffles me personally, but I can understand that they wouldn’t know if they literally left all of the cooking work up to the women in their lives.
Rice is the food I don’t think I could live without. 
This is because rice is what usually ends up satisfying me and you can eat it with almost anything or by itself. It’s an extremely versatile food that’s also simple to prepare and make in large quantities. So it would be a food that I would definitely miss.
I think it’s interesting that you focused on your fulfillment when it came to explaining your favorite food. I didn’t put much thought into whether food is satisfactory in terms of fulfillment. I too am very tied to my culture.