I have sung professionally in the past and this suggested diet would not provide you with enough nutrient to be able to give you enough stamina to sing for one night, let alone everyday. Singing takes a lot of energy.
Balance is best, in diet and everything else in life.
Raw honey is great for singers, a spoonfull before performing and several over the length of the performance, really helps.
I also found that salt water gargling before and after performing was very helpfull.
Silica for vocal chord strength is a must.
Hopefully this problem you are having is a temporary thing.