I don't have BPD but one of my best friends has it; like you, she initially was overwhelmed by depression and had a lot of problems with getting motivated physically. She doesn't have PTSD, but I do (as well as ADHD-C and MDD).

Since her and I didn't have the same diagnosis but often overlapped on medications, we compared a lot of our issues with activity level and dieting. We were often on the same SSRI meds, and a lot of the things they tried with her I'd been on in the past when they weren't sure if I had bipolar.

We both struggled with unhealthy relationships with our diets, in different ways but both bad.

We both binged at points; I often had struggles with appetite throughout the day, which would lead to rapid consumption of *anything* later on, followed by depression and insomnia, etc.

She would often eat emotionally; lots of sugars and carbs mostly, anything you could eat constantly.

But, it got real concerning when she felt the worst about herself; not eating became a sort of...satisfying punishment? She'd view eating/not eating as a reflection of her character.

It sucked, because she was obese at the time, so people wouldn't take her seriously when she refused to eat.Nobody considered that part of the reason she struggled to lose weight were these cycles of starvation-and-tonsoffood. Some of it was her build (and she does actually have some health issues that contribute to her size and composition), but a lot of it was stuff like this.

I also struggled too; I lost a lot of weight when I motivated myself with negative self-talk. I was still eating, but it was easier to eat spinach+lots of fruit+ beans as protein, everyday (I worked at the grocery near the salad bar so it was easily accessed) when it all tasted the same due to being depressed. I just sort of...zombie walked throughout the day, and before I knew it, I'd started losing weight.

But both of us would always rebound. That kind of motivation isn't sustainable; either you end up in the hospital (which she ended up at some point), or your body will eventually say "ENOUGH" (like it did to me, and I ended up bingeing due to poor nutrition and suddenly missing food). And both of our bodies were worse off; neither of us really got that 'healthy slim' or anything, and we looked very sick.

In actuality? I've become healthier following the slow-and-steady route than the harsher ways we were treating ourselves a few years ago.

I don't know if this helps at all. I can give more details on her lifestyle now (and compared to 2-3 years ago when she was first diagnosed) or mine as well.