Will eating raw food have a negative effect?

Solution 1:

No, you can consume raw food all you like. Even raw clams and raw meat will never cause ill effects. You can drop it on the floor, stand on top of it, drag it through the mud, leave it in a box in your house for weeks, and then chow down as if it was fresh.

It's not really worth much as far as restoring your stats, though. Even cooked, most foods aren't worth the effort. Sink some time into learning a few basic alchemy recipes for restore health and you'll be far better off.

Solution 2:

As with all items that may be consumed, your player can learn what effects come from each items. whether it be a increase in health, or a resist to fire. All consumables have up to four unknowns. By eating it, you find out one of them.