Hi! I have to say 600 calories is terrible! You are going to starve your body. On average without exercise, your body burns at least 1400 calories, if you are eating only 600 calories you are not fueling your body with proper nutrition. When this happens your body goes into starvation mode and you end up gaining weight to, worse yet, end up sickly. Don’t do that to yourself, please! When I added more calories into my diet, I gradually added more, like a 200 a week. I gave myself an extra snack. I don’t recall if I gained weight at the beginning, but I do know I lost weight when I ate more. Don’t be afraid to eat!! What I would do if I were you is add more protein into your diet, like eggs, greek yogurt, lean chicken. You also need a little fat like avocado, olive oil or peanut butter. I personally found the hardest thing about dieting is not being able to stick to it. I dieted for 2 years lost weight, but then life happened. I eat healthy but what I started back when I was dieting I was eating low calorie, now I eat what normal people eat and I gained some weight back. But I realized what I was doing to my body back then, I wasn’t able to do that for the rest of my life. My advice is to eat healthy, eat what is in your calorie range and exercise for 30 minutes a day, even if it is just a walk. Doing this is a set-up for permanent weight lose and you will be healthy. I learned over the years that a healthy body on the inside, shows on the outside and even if you gain a little weight you are better off.
Sure, you can lose weight quickly. There are plenty of fad diets that work to shed pounds rapidly -- while leaving you feeling hungry and deprived. But what good is losing weight only to regain it? To keep pounds off permanently, it's best to lose weight slowly. And many experts say you can do that without going on a "diet." Instead, the key is making simple tweaks to your lifestyle.