I watch videos of fat people to make myself feel better
That sounds awful. Why would watching videos of overweight people make you feel better about yourself?
Because I'm jealous of their physique, thus creating a feeling of inferiority
If you have concerns with your own physique and appearance, you shouldn't watch videos of other people just to compare yourself to them. Instead, you should work on your own self-confidence and self-esteem to be mentally healthier. Talking with a therapist could be helpful to navigate the problems that you are having with accepting your physique.
But I want to feel better, who cares about others.
If you're jealous then look for ways to improve your own physique. Wanting to be over weight isn't a good thing to envy anyways. Being overweight can lead to all kinds of health issues down the road.