When you’re sick, why does your appetite often go away?



I’ve noticed that with certain sicknesses, I tend to go most of the day without eating anything; if not all day. Usually just for one day though, then I get my appetite back. Normally (when I’m not sick) if I go a few hours without eating I get “hangry”. I’m used to eating quite a lot throughout the day though because I have a fast metabolism. So (for me it happens with tonsillitis or stomach bugs) why is it that when you’re sick you don’t feel inclined to eat? Doesn’t your body need food for energy to fight the sickness? And why does it seem that only certain sicknesses suppress the appetite?

In: Biology

Maybe your body is trying to starve out the bacteria?

attrition. In a bacterial infection, your body pumps out different hormones to fight it, one of these lowers your glucose levels, which is what the bacteria eat, so your body is trying to starve it out.

I am not 100% sure, but the first thing that came to mind is the sympaticus/parasympaticus (maybe not the right translation, ESL). Basically, the sympaticus is the “fight or flight” mechanism which shifts your energy consumption from your complex mental processes and digestive system towards your muscles and other tissue which needs the energy more, as is the case with inflammatory reactions and infections or other dangerous situations, so the organism can deal with the threat more effectively (sped up heart rate, faster breathing etc) Similarly, the parasympatic system does the exact opposite, slowing your organism down and activating your digestive system so you can refuel/regain energy.

Again, I’m not 100% certain and I might have gone too wide with this, but that’s my assumption, to say the least.

Perhaps it’s because if food made you sick, a probationary period where you don’t eat is a good idea? That way you don’t continue to ingest more of the virus or bacteria.

I can’t answer your question, but it looks like some people have already discussed it, so I ‘m sure you have an answer by now. However, I used to smoke cigarettes and when I would get sick I would not have any nicotine cravings. I actually used that to help myself quit. I had a cold and went several days without smoking. When I started feeling better, the nicotine cravings came back, but not as strong. I wonder if there’s any relation.

You gastrointestinal systems use a lot of energy. If you have an infection, the immune system demands that energy instead.

> I’m used to eating quite a lot throughout the day though because I have a fast metabolism.

Your metabolic rate is not a static value. Its a rate at which you metabolize energy, sleeping and its lower, running up stairs, higher. And the background rate of burn does not vary by more than 300kal at the extreme between people(half a meal).

Because you just feel like dying no one listens to you or actually cares about what you feel so there is no purpose to keep going on like this :/