As your body is made up of repeating segments, a change which produces a particularly pointy segment at the front is pretty easy to produce, and means you can become a pretty effective hunter of anything small enough for you to then ingest in one go.

You can’t eat things that are bigger than you, because you’ve no means to chew them up, but it works. Could be better though. You need a way to chop your food up to make sure you can get as much as possible.