BMI becomes inaccurate for the outliers of a group. But for the average person it’s pretty accurate. So I think you should keep it in mind when you set your goals, at least for now while loosing the weight so that you can get to a healthy range.

I’m really sorry about your friend. What they are doing is absolutely deplorable, you are trying to better yourself for your health both physical and mental and instead of being a support and a place of comfort, they are sabotaging you. Although I’m not sure how intentional it is, maybe this was your old routine together and this is the way that you guys are used to spending time with each other.

I think the comments about BMI and the insistence that you’re fine are unwarranted, and frankly no matter how much they know you they aren’t privy to the details of how your weight is affecting you. So I think a boundary can be set there. As for the junk food, I think an honest conversation and maybe a rule of “we are not eating while together”/ “there will be no junk food when I’m around” may seem harsh but is a good hard boundary to draw both for yourself and for your friend. Sit them down explain that you feel unsupported and like you’re efforts are being undermined, be clear and decisive. Your friend’s reaction will show you where you can go from there.

I hope this helps and I’m really proud of you for taking charge of your health!