As a recovering bulimic, I recommend IIFYM as a diet, since it's something you can maintain healthily indefinitely, and it helped me overcome my bingeing issues. I can now eat one fun size snickers and put the pack back in the cupboard. (!!!)

I'd recommend weight training as well, because I think it really helps you change the way you think about your body. You start thinking 'strong' and instead of 'skinny'.

Also, when you start weightlifting, you are constantly setting yourself goals and meeting them as you progress, so you get this feeling of achievement associated with your body that previously I only felt when I lost weight on the scale, starved myself, or purged.

Weightlifting improved my mental health and depression so much I can't even really stress it enough. It's so different to doing cardio and thinking 'i burnt xx calories!' because you literally see your body change, and you become stronger and stronger every week. Pretty much you are setting yourself up to succeed with a beginner weightlifting program, unlike any other exercise. The improvements start from your very first workout, you don't need to wait weeks to see them. Noob gains mean you will be adding weight pretty much every workout for months. Which feels great.

Weightlifting for me is this constant source of positive healthy body-related feelings. I work out and increase a lift and feel great. It's not something i do as punishment or to make up for eating like cardio used to be for me.

(and no, i didn't get bulky.)

for ref: me at 70ish kgs, i got bigger than this, but i avoided photos. Me this morning. (NSFW panties and slight underboob)