I frequently eat less than 1000 calories a day, but I just d

I typically eat between 800 - 900 calories a day. I don't stay under 1000 on purpose, I just try to only eat when I feel hungry and stick to healthy food options. I eat mostly chicken, fruits, veggies, and egg whites. Sometimes I get pretty close to my 1210 calorie limit, and some days the only reason I stay under is because I exercise and burn off the extra calories. I started losing weight at the beginning of January this year, and so far have lost 24 lbs. I feel great, have lots of energy, and my immune system has gotten a huge boost. I'm just concerned because I keep reading that eating less than 1000 calories a day will eventually catch up to me, and that when I've lost all the weight I want to lose, when I loosen up on my eating restrictions, I will gain a ton of it back.