Undereating.. High-Kcal Snacks or Meal Ideas?

I’ve struggled with undereating for a while now, and it wasn’t until my mother pointed it out that I actually noticed. I used to be dieting, obsessed with this figure I wanted to be, but now I can barely manage to eat over 1400kcals a day including a midday and nighttime snack. I used to be stuck in the routine of digesting only 700kcals-1000kcals a day, and I would usually not eat the next meal if I felt guilty of something I had ate earlier. For example, my goal is around 2000kcals, but today, eating whatever I wanted to eat, I only ate 1300-1400kcals. I have lost a fair amount of weight since last year, as I used to weigh 12st 7lbs and I am now only scraping 9st/8st 11lbs. My jeans — size 12 — are even getting too big for me now, I brought them in the last months. My goal is to be able to maintain/gain a slight bit more in order to fit into them again.

Usually, my snacks consist of a Greek yogurt (78kcals), a Muller Corner (120-200kcals), fruit and yogurt, etc. I usually tend to steer clear from heavily processed chocolates, but I eat them every once in a while.

Is there any advice on more calorie-sufficient meals or snacks I could make/take to work with me? I eat a lot of fruit and vegetables, and I believe I subsitute too many proteins and carbohydrates for them. The only proteins I eat are Quorn, chicken, turkey and ocassionally pork.