Calorie deficit

It all depends on what your BMR and TDEE are... Regardless, never net below 1200 calories a day PERIOD. that means eating 1200 calories and then eating back more cals from what you burn due to exercise.

It is located under your goals section. It's how MFP decides how many calories you need to eat. Stick with it a week or two and if you don't see any chances, then post again for suggestions. You have to trust in the process. This is my second week and I've already lost 1 kg (2.2 lbs). It does work!!

http://www.myfitnesspal.com/topics/show/654536-in-place-of-a-road-map-2-0-revised-7-2-12

Go there. Read a little scroll down for the site he gives to do all that BMR TDEE stuff.

These will explain...

You most likely need to eat quite a bit more....

http://www.myfitnesspal.com/topics/show/186814-some-mfp-basics

http://www.myfitnesspal.com/topics/show/61706-guide-to-calorie-deficits

http://www.myfitnesspal.com/topics/show/819055-setting-your-calorie-and-macro-targets

3,500 calorie deficit is regarding losing a pound of only fat. But when you lose weight, about 25% of your loss tends to be muscle, maybe 25-50% is water (I honestly forget), and about 1/4 is fat.

That is why working out is important in maintaining a weight-loss program. It offsets the amount of muscle that you lose, and more of your actual losses will be fat and water.

If you lose 2 pounds every week, that is *not* the same as losing 2 pounds of fat that week. Just like when you gain 2 pounds, it is not usually 2 pounds of pure fat, but a lot of it is just momentary shifts in the food that you've eaten, plus water retention. Now, if you gained 4 pounds in one week, and didn't lose it over the next 2 or 3 weeks, the weight would be retained and would eventually represent a gain in fat tissue, and not just water and food weight.

Other posters are right: don't go under 1,200 calories every day. Be comfortable with MFP's 2 pound loss plan, but be aware that not all of your weightloss is purely fat cells shrinking. Without regular exercise, some of that loss will just be water weight and muscle.

BMR (basic metabolic rate) equals how much your body burns if you were to lay in bed all day, even in a coma
The bare minimum your body needs to function. This depends on your weight height and age. For examples sake, mine is 1200


TDEE is your Total Daily Expentidure. That is your bmr plus any exercise and any incidental exercise (hanging out the washing, doing your grocery shopping etc.)

If you ate your TDEE amount, you'd just maintain your weight. And a deficit means you'll lose weight. When you put in your TDEE into MFP put it as sedentary and then log in your exercises on top of that. Your net calories are then everything you ate, minus your exercise and this number should never go below 1200 or it also your metabolism. In fact creating too big a deficit will do the same which is why you need to know your tdee number (if you opt for sedentary its your bmr X 1.25). A deficit of 300 is usually recommen , or up to 500 if it doesn't go below 1200)

And yes that means eating back your exercise calories. You should be NETTING at your calorie goal.

Google bmr calculators to find out yours...