I came upon this alternative healing webpage. Interesting enough, there is a section there about what food should be eaten by a dengue patient. It did not state why specific foods are allowed or not. Anyway, it is always best to ask a doctor first.

Although Dengue fever can be extremely unpleasant, it is not usually life-threatening. However, whilst this disease might not have you taking out life insurance policies at sites like http://www.aviva.co.uk/life/ it is more than likely to make you consider what foods you can eat to help improve your condition. After all, it is always a good idea to supplement medical treatments with more natural remedies.

This site makes a number of useful suggestions for those suffering from Dengue. Many of the items listed below are everyday foods, that would not be difficult to incorporate into a patient’s diet. Here are the recommendations from The Ayushveda.com:

Dengue patients main meal should consist of rice gruel and boiled vegetables. Oil is a no-no and so are spices, including salt, although lemon juice may be used to flavor bland dishes. Porridge, baked toasts, or biscuits can be eaten for snacks throughout the day. Tea must be made of fever reducing herbs such as ginger and tulsi. The only fruits that can be eaten are apples and plaintain.

Source: The Ayushveda.com