I can't believe some people saying 1,600 calories a day isn't enough. 1,600 calories a day is more than enough for the average person. Unless OP is exercising like a demon every day, she doesn't need more than that. Peoples idea of how much 'food' we need makes me weep and tbh goes to show why so many people have serious weight issues. The fact is, losing weight on 1,600 calories IS working for OP - so we should be supportive of that rather than telling her to increase her intake. All OP needs to do is adjust the quality of what she is eating.
OP - I had 1,300 calories yesterday (most days I eat about 2K as I do a lot of exercise, but yesterday I was lazy and adjusted my calories to reflect that). I don't eat snacks on days I don't exercise as I am a picker.
Breakfast was: Greek Yoghurt, home-made granola (basically just nuts and dark chocolate), one apple chopped up, cinnamon, (400 calories)
Lunch: 200G Rump Steak, 150G Broccoli, 300G Beansprouts. (400 calories, including seasoning such as garlic, ginger, coriander, red onion which has basically no calories etc).
Dinner: Chicken breast wrapped in Parma ham stuffed with cream cheese and spinach. Mediterranean vegetables (in the oven, no oil but lots of seasoning) and 200G asparagus. (500 calories).
As with anything, it's about the quality and quantity of what you eat.
For days you're working (assuming you're going into an office) try a homemade yoghurt bowl or homemade breakfast muffins (with egg, chorizo instead of sausage, cheese and red pepper - you just mix it together and pop it in the oven a few days before. They reheat nicely or you can have them cold). For lunch try homemade marinated chicken breast with vegetables or a big salad or a 'fancy salad' (I have a butternut squash, rocket and blackberry one I do). For dinner, something high protein (Chicken, Steak, Salmon) and bulk up with vegetables - don't do carbs like pasta as tbh it's satisfying at the time but not filling and not really nutritionally 'dense'.
Don't forget seasoning. Seasoning really changes a meal. The mistake so many people make is trying to have things like soup or fruit and yoghurt or chicken and rice and veg and they forget about seasoning - any diet or restrictive eating will fail if you don't give yourself variety.