Calories

So I'm watching the Biggest Loser, Couples series (probably way behind you guys though). The episode I've jus****ched is where the blue team lose hardly any weight at all and one man even put on 3 pounds. Now these people are working their butts off in the gym, and it turns out they are eating 500 - 1000 cals per day!!! With that you'd think they'd be dropping the big numbers, but Jillian was saying that the low cals is exactly why they didn't lose much and that they HAD to eat the right amount of calories. Hmmm...and I put it all down to the amount they worked out for the huge loss we see them having. So I guess what I'm saying is that it was a light bulb moment for me. Yes, I know there have been many posts saying eat more, but haven't really believed it - after all, cals in verses cals out should balance surely?????? I get daily emails from Jillian (trying to get me to sign up to her program) but also gives daily hints on losing weight. I have 2 of a three part info on how to calculate the amount of calories you should be eating to lose weight. I get the next installment next Friday. I've posted the forst two on my profile if you want to take a look. I'll post all three next Friday when I get it. How have you all calculated how many calories to eat per day?