Yes it is true.You should eat more when you are ill because you will be tired or you will lose your energy when are ill so you need energy that time and the only things that will give an energy is the food and fruits so you need to eat more when you are ill.I am doing this and you can also do this.The doctors also gives you like this advice.

Its normal , dont feel bad, just eat and enjoy

I can not eat any thing while i am ill, i take just few drinks and nothing els,
but when i recover i feel i eat more then my normal routine.

Of course it is fact as at the moment when we get ill, we need more energy and power so we have to eat more. And unconsciously we do so many times.

well that is normal may be. when my sis and my dad gets ill they eat all the time but not too much i mean when they feel hungry they say they want to eat something good to taste. but when i got sick. i stop eating any thing even if i am feeling hungry when i was completely well then i start eating things. well every one is different you are unique piece. :)