Man cannot live on bread alone – not least because man would develop scurvy about a month or so into that little experiment. The best diets have plenty of variety in them. In the extremely unlikely scenario that you had to live on just one food, are some nutritionally more complete than others? Could you get what you need from, say, just potatoes, or just bananas, or just avocados?
http://www.bbc.com/future/story/20170224-what-food-would-keep-you-alive-the-longest
