I agree with Bence Dobos. The two sentences don't have quite the same meaning. If you are not used to eating spicy food, this means that you don't do it often - it's not your habit to eat spicy food. But perhaps you could get used to it. If you can't handle spicy food, it means that your body can't cope with it. Perhaps it makes you ill.

People who are not used to eating spicy food also can't handle spicy food. But there are people, like me, that no matter how often they eat spicy food, they still can't handle it. So there are two different situations. In your sentence I think I would choose to say, "You might cry if you can't handle spicy food." The other expression just came to me first.

Well the two mean quite different things in my opinion.The first is : even if you like spicy food, you can't eat it, because it's bad for you, while the second is more like: You can't eat it because you don't eat it that often and it differs from what you usually eat, but if you ate it regularly you'd get used to it.

For me personally, I can't handle spicy foods. And it is also the expression I have heard most often from people around me.