I think GC last fell ill around the same time this year. (I cant recall one day when he fell during this last year). Due to seasonal changes a lot of people catch the viral during this season esp if the climate of the regiona does not suit you. I was in Mumbai last month and believe me there was 3 days of continuous rainfall (it did not stop even for a minute), so u tend to get infection soon, esp if your immunity is low.
Young people who are into body building and workouts try to stick to a low carb diet with more of protein and vegetables, with less spices and oil. It is just not GC, i recall in an interview even Karan Tacker and Karan Wahi said the same thing about their diet. GC must be following a dietations plan so i dont think his diet is responsible for his illness. During the rest of the year he looked perfectly hale and hearty to me and full of energy in his acting, dance etc.
So stop find faults with him again.