Is It Bad To Eat Fast Food When Sick. Big mac 550cals (46g carbs, 29g fat) large fries 500cals (63g carbs, 25g fat) But that’s not the real problem the food in your belly swells up as it socks water in your belly and expands ,this feeling makes you constipated and clumsy.

However if you eat a certain way 90% of the time and only eat differently once in a while, then you will have adapted back to your normal diet between each of those cheat days. But that’s not the real problem the food in your belly swells up as it socks water in your belly and expands ,this feeling makes you constipated and clumsy. With something to be said theoretically both for eating and fasting while sick, practically speaking, it’s best to rely on your own body’s signals.