Even though he may not be expecting a serious long term relationship with you, he is trying to extend the BDSM relationship outside of the bedroom, which, in his mind, WOULD make you an object, and one that belongs to him. It's common in BDSM relationships for the dominant partner to have complete control and that includes telling you what to eat. In his mind, he IS probably trying to keep you healthy. HOWEVER, 2 things. 1) He doesn't understand the implications of an ED and how his comments can have an impact on that. He probably thinks that telling you that you would look good if you gained some weight is a compliment and will help you feel more comfortable with eating more. 2) I would be very wary of someone who is taking on a dominant role in the relationship without your EXPRESS CONSENT...Unless a relationship like this is discussed, in detail, and both parties are comfortable with the terms, then it's not a true dom/submissive relationship. He should know this already, there are social standards in the BDSM community and his failure to follow them means you could be putting yourself in a situation with someone who could potentially be very dangerous, both to your mental well-being and your PHYSICAL well-being. I suspect that you know a lot about this already, but might just need a 3rd party to point it out. Good luck with everything.