Why we are normally advised to take bland and nourishing food when we are sick?

When we fall sick, one or more organ-systems do not function normally. As a result, we lose appetite and do not have proper digestion ability and absorption of food is slow. Sickness makes us weak and it takes long time to recover. Therefore, we are advised to take bland and nourishing food during sickness. Such a food is easily digested and replenish our lost vitamins, minerals and other nutrients along with energy.