My spouse overeats – what to do?

I noticed that he gets into periods where he’ll overeat and over snack and gain weight. If we’re at a social gathering where there’s so much food to try, I’ll notice him constantly munching on something, and then afterward he’ll “beat himself” up about it and make himself feel really bad. He says sometimes he’ll overeat at work too because they get free food and work is really stressful for him. Then he’ll shame himself and go on a strict diet and work out routine. I know his mom always comments on when he’s gained weight in his face and that’s another cue for him to “get back into shape”. Sometime he’ll ask me if I think he’s fat. I know he used to be much larger as a child, so there must still be some insecurities from childhood.

So the cycle continues on and on – overeat, intense diet/work out, overeat. He says he gets endorphins from eating and that he’s “addicted” to it. I honestly have never had an issue with overeating, so I don’t fully understand where he’s coming from when he talks about it, but I want to help. Am I allowed to do anything to try to help him? Or do I let him go on doing these things to his mental health and body? I understand adults will do whatever they want and I can only control my actions, but it’s really disheartening to witness.