To get my calories up, I added healthy fats like avocado and hemp seeds. I stopped buying low fat cheese (except string cheese and babybel- prefer lowfat there). I also added more fiber rich foods like carb balance tortillas, fruit and veggies. My carbs are up but they are healthy carbs. I did add one food that could be considered a slider but it is healthy, dry roasted edamame, 1/4c is 130 calories and 14 grams of protein. I can eat 1/2c of those buggers. I would try for 800 cals for a couple of weeks and then 1000 after that.