system
Given the following post, respond as if you're commenting on Reddit:
human
Do immunity-boosting foods really exist? And what's the exact mechanism by which these foods boost immunity?
gpt
You could harm your immunity by eating a really bad diet, but living in a Western country you’d have to work pretty hard at it. If you eat a remotely standard diet, you’re doing just about as well as you can, immunity wise. (Unless you eat too much, since obesity is associated with increased susceptibility to many disease, for many reasons, including some effects on immunity. If you’re overweight, though, adding foods to your diet won’t help your immunity.)

If you’re looking for a way to boost your immunity (again, you’re not making it better, but you can stop making it worse) don’t look to diet, but sleep. Sleep deprivation is probably the most common cause of mild immune suppression in the west, and it’s the easiest to fix. Of course, hucksters can’t sell a tin of sleep for $49.99 (plus shipping).