Eating enough calories a day!

If you consistently eat larger portions and more frequent meals your stomach will stretch and you will no longer struggle to consume a larger amount.

Be careful with that BMR by the way... yours is probably closer to 1650 than 1900 and it will go down as you drop weight. You could probably lose weight quite fast and get fit by eating 1600-1700kcal a day and doing light to moderate exercise for about 30-45 minutes.

If you consistently eat larger portions and more frequent meals your stomach will stretch and you will no longer struggle to consume a larger amount.

Just to correct you your stomach does not stretch outwith of normal bounds except in exceptional circumstances. What is off is the posters hunger signals and the more she eats eventually they will kick back in. A normal stomach will hold around a litre of food and if really pushed to extreme around 4 litres but this is still within normal capacity. The only time your stomach will stretch is if you're something like a competitive eating and than it can be dangerous and they have spent a long time pushing pints and pints of water to do this.

Maybe instead of eating 3 large meals, try eating throughout the day, then you'll never be super full. Also, if you're eating a lot of low cal weight loss products then maybe instead try eating 'clean' or 'real food' or however you want to put it. If you're having trouble reaching calories then don't go for calories restricted fake food (supposed to fill your up with little cals) but rather try to follow to a food guide or something to try to get protein/dairy and fruit/veg into each meal (assuming you're not vegan or lactose intolerant or gluten free etc etc, then modify as needed). The biggest thing with not getting enough calories is not getting enough nutrients and your body going into starvation mode and doesn't work efficiently. It needs glucose for your brain and energy, and protein for your muscles and healthy fat for your cells (ie olive oil). So you don't want to just eat anything to up your calories, but rather give your body what it needs to serve you best. If you have salads then use/make olive oil based dressings, it brings up your calories in a healthy way. I try to have one protein and one fruit/veg at every meal with some carbs thrown in there. For me it usually ends up looking something like this:

breakfast - vector cereal, almond milk, fibre buds (protein and fibre) or instant oatmeal (carbs/filling)
snack - yogurt (protein) and berries (fruit/antioxidants and all that good stuff)
lunch - pear (fruit), 1 cup pasta (carbs) w/feta (protein), tomatoes (veg, antioxidants), and olive oil/pesto (healthy fat)
dinner - ham steak/steak/chicken (protein) and 2 cups frozen veg (veg) with garlic chili olive oil (healthy fat)
dessert - cool whip to satisfy my sweet tooth without getting ice cream :P (not 'clean' at all)

This usually gets me around 1200 cals - if I work out, I eat more - ie apple and peanut butter - so good! or you can make a high calorie awesome shake with chocolate protein powder, spinach, peanut butter, mixed berries - so good, filling, healthy and high calorie, and you don't taste the spinach at all, my roomies make them all the time. Just watch with protein powder scoops - your body can handle about 20grams of protein at a time and the scoops are 30grams so don't waste that 10g of expensive powder, just don't fill the scoop all the way. My BMR is around 1700 cals a day so this is set up for me for weight loss, but once I get to my goal then I'll up my food so I'm at my BMR and not in deficit anymore.

Anyways, I hope this helps. I, like most people, am an over eater opposed to an under eater like yourself so I can only say so much. Good luck to you!

Eggs! Butter! How could I forget about those delicious things! Yes eat these, just as they are (well, cooked for the eggs is fine :P)!