Edit: I assume the downvotes are for not contributing to the discussion appropriately. Fair enough:
While people can subsist on beans and rice and/or potatoes, they have a medium to high glycemic index. Also, to get adequate nutrition from them, one will take on a higher glycemic load. These are major contributing factors in diabetes and cardiac disease. It can be mitigated with preventative healthcare, which is something people living on these diets may not have reliable and affordable access to. People subsisting on starchy foods alone live sicker, shorter lives.
Potatoes also have enough nutrients that you can pretty much subsist on them alone.
Diabetes has entered the chat.
Edit: I assume the downvotes are for not contributing to the discussion appropriately. Fair enough:
While people can subsist on beans and rice and/or potatoes, they have a medium to high glycemic index. Also, to get adequate nutrition from them, one will take on a higher glycemic load. These are major contributing factors in diabetes and cardiac disease. It can be mitigated with preventative healthcare, which is something people living on these diets may not have reliable and affordable access to. People subsisting on starchy foods alone live sicker, shorter lives.