I eat around 500-600 calories every morning. I need it with the amount of exercise I do. I nearly always have crunchy oats granola bars and something else. I eat those bars 2-3 times a day anyway. I go lighter for lunch ~400, and supper is 200-300 most nights. I'll have several small snacks during the day too. On my big workout days, usually just Sunday at 4 to 5 hours of full on, I'll eat about 2200-2500 calories and burn around 2800. I finally started losing weight again! I think my muscles have plateaued for the type of exercise I do, mostly cardio.
We don't need as much protein as people think. Two tablespoons of peanut butter solves the protein necessity for an entire day. I'll also say fats are not the enemy. Sugar is. The sugar industry paid the US govt to say fats were the problem. Yep. Straight up bribed. I'm not saying eat all the fat you want, but be mindful of what you're eating and how much your body needs.
Also, calorie counts on labels are allowed to be off by as much as 25%. Yikes?