system
Given the following post, respond as if you're commenting on Reddit:
human
Why is partially hydrogenated oil (or some variation) in so many types of processed foods?

Is there a certain chemical reason to it? Why is it so universally used?
gpt
It's cheaper to partially hydrogenate a vegetable oil than harvest an animal oil with similar properties. Hydrogenated oils have longer shelf-lives before they go rancid. You can also customize the oil's properties somewhat by controlling how it is hydrogenated.