What is the best food that I should eat to be healthy?

Everything. You need to eat 3 times a day. It all depends on your motivation to beat the addiction to eat. You only know the answer. Talk to dietician, but you have to apply the discipline.
Alkaline foods. Learn about epigenomes you can turn them on by eating foods that supply methyl groups - here is to learn more - http://learn.Genetics.Utah.Edu/content/epigenetics/.