How do you follow a diet when food is your only stress-management mechanism?

I’m an obese college student, and I’m struggling with something that feels really basic but really hard to fix.

I don’t drink, I don’t smoke, I don’t party. My only coping mechanism when I’m stressed, overwhelmed, or anxious is eating. It’s the one thing that immediately calms me down. Because of that, every time I try to start a diet or a weight-loss plan, it completely collapses the moment life gets stressful. I end up eating my feelings, then feeling guilty, then giving up altogether.

I’m trying to change my lifestyle, not just lose weight for a few weeks. But I genuinely don’t know what to do when the thing I use to soothe myself is the same thing I’m trying to control.

If anyone has been through something similar or has strategies for breaking this cycle, I’d really appreciate it. How do you manage stress without turning to food? How do you build new coping skills when the old ones are the only ones that feel like they work?