My head is spinning, with your question as well as the responses! PLEASE READ my post carefully, because I care about you and your weight loss success!!!
First of all, how is it that you consume exactly 1287 calories a day?! Do you eat the same exact thing every day? 1287 may not be enough for you...please continue reading!
A calorie is a unit of energy, so you can't really eat them, can you!
Also, you don't just burn calories running. We burn calories by walking around, doing chores, sitting at the computer, showering, talking on the phone, shopping, etc. I'll explain more later.
Resting metabolic rate is ONLY the amount of calories one burns just to function...your nervous system, heart, kidneys, lungs and all other organs and all bodily functions such as digestion, brain function, maintatining core body temperature, etc. So if your resting metabolic rate is 1400 (I don't know your height, age, or weight, so I'm just saying this as an example), YOU NEED TO CONSUME AT LEAST 1400 calories a day to properly function! This means if you are in a vegetative state of lying on the couch for 24 hours, your body needs 1400 calories just to function properly!
Now, you're probably not in a vegetative state. You go to work, go running, do laundry, walk around inside your home, go shopping, eat, watch TV. ALL OF THESE ACTIVITIES BURN CALORIES. Therefore, you need to consume MORE calories to do these activities. So if your RMR is 1400, you need to consume, I'm approximating, 600 more calories FOR ALL LIFE ACTIVITIES. So you need 2,000 calories to MAINTAIN WEIGHT.
Now, you want to lose weight. Since you need 2,000 calories to meet your RMR and DAILY ACTIVITY NEEDS, you can cut 500 calories safely. This is through exercise as well as calorie reduction. So you can go running and burn 300 calories, plus reduce your calories by just a mere 200. So that's 2,000 minus 200 = 1,800 CALORIES YOU NEED TO EAT EVERY DAY.
Again, 1400 RMR is just an example. Here's me. I'm 5'0" and weigh 105. My RMR is approximately 1,000 give or take. I exercise, shop, work, cook, clean, walk around the house, eat, do laundry, watch TV, brush my teeth, etc. For the amount of activities I do, I need IN ADDITION to 1,000 calories, 700 calories MORE. So, 1,000 plus 700. I need 1,700 calories per day to maintain my weight. If I decide to lose weight, which I'm not, I reached my goal weight last year, but let's say I did. I can reduce my calorie intake to 1,200 and lose weight pretty well. I'm still including all my exercise and activity. Now, let's say I want to lose weight even faster and I reduce my calorie intake to 700 calories. THAT'S BELOW MY RMR. I will lose a bit of weight, but then my body will go into starvation mode and I won't lose an ounce, I may even gain weight because my RMR has slowed to a screeching halt! I'm affecting my heartrate, I'm cold all the time, my liver, kidneys and lungs aren't functioning properly, and I'm living with brain fog all the time. NOT GOOD!
Right now, you may go into starvation mode is 1287 is below your RMR. You even say yourself that you are starving at bedtime. That's your body's way of telling you that you are overdoing it. You are not eating enough and you are exercising and burning even more calories than you even have to spare. Your RMR will SLOW DOWN and you will be stuck at not losing weight, or even worse GAIN weight!
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