어서요

Because — answering politely

It gives the reason on its own, and in most of these lines it is the entire answer to a why question: because I want to feel full of energy, because it is healthy and not expensive, because there is no producer free for the schedule. The 요 on the end makes the fragment polite, so no full sentence is needed. Compare 으니까요, which is closer to since and can sound more like an argument.

Register: polite conversation