Need information of increasing calories :)

I have as of today raised my calorie intake up to 1500 a day, I have been under eating below 1000 calories a day and also burning around 450 calories a day for around 1 month and a half, I haven't been eating my exercise calories back either. I was just wondering how raising my calories would help me lose weight as my weight has recently come to a holt and I've started gaining. I know I will initially gain weight by increasing my calories, but I have patience to wait for the good results. I was just wondering how long will it take roughly to stop gaining weight and start losing. How does it actually work? any help would be appreciated thanks x

Raising your calories won't help you lose weight faster, it will help prevent you from damaging your health.

But would you be able to explain to me the concept of increasing my calories then?

Sure. Everyone's body requires a certain caloric intake to support all of its functions and maintain its weight. This value can vary from person to person slightly but you can use calculators based on population averages to get a good idea of what that value is. Here are two:

http://exrx.net/Calculators/CalRequire.html
http://scoobysworkshop.com/accurate-calorie-calculator/

If you want to lose weight then you want to eat slightly below that value to create a calorie deficit. Your weight loss will then be 1 pound of fat per amount of time it takes to build a deficit of 3,500 calories. Your deficit should not be overly large and what that restriction is depends on how much weight you have to lose.

Using myself as an example I require about 2,600 calories per day to maintain my weight. I want to lose about 1 pound per week which would be 3,500 calories in a week or 500 calories in a day. Therefore I strive to eat 2,100 calories each day and as a result I lose weight.

If I were to eat instead 1,100 caloires a day I would lose weight considerably faster but I would also be malnourished which would negatively effect my energy level, organ health, brain function, etc AND the weight I lost would be not only fat but also muscle and bone density.

The less you eat the faster you lose but you want to eat enough that you aren't losing muscle, bone and your overall health in the process.

Generally that means not eating less that 20% under your total caloric burn if you are 40+ pounds overweight and a smaller deficit if you have less than 40 pounds to lose.

I do cardio for a good 35 minutes a day, I have been eating under the adviced 1200 calorie minimum, I still want to lose weight, so how do I go about this? Do I need to increase my calories for a period for my body to get used to it and then decrease my calories? And if so, how long do I wait to decrease my calories, and how many calories should I be eating if I'm excercising? Sorry for all the questions

MFP is a calculator, it doesn't advise you to do anytthing...it just spits back what you tell it. If you tell it you want to lose 2 pounds a week it will tell you how little you would have to eat to accomplish that. 1200 is literally the lowest it will go so if it is telling you 1200 it is essentially giving you an error message that should tell you that what you suggested (like 2 pounds a week) is far to aggressive.

Honestly if you are doing 35 minutes of cardio daily I would think that you would want to be eating like 1800 calories a day for weight loss, certainly not 1200 and DEFINITELY not less than 1200.