Basal Metabolic Rate (BMR) is the total number of calories your body requires for normal bodily functions (excluding activity factors). This includes keeping your heart beating, inhaling and exhaling air, digesting food, making new blood cells, maintaining your body temperature and every other metabolic process in your body. In other words, your BMR is all the energy used for the basic processes of life itself. BMR usually accounts for about two-thirds of total daily energy expenditure.
The first step in designing a personal nutrition plan for yourself is to calculate how many calories you burn in a day; your total daily energy expenditure (TDEE). TDEE is the total number of calories that your body expends in 24 hours, including all activities. TDEE is also known as your "maintenance level". Knowing your maintenance level will give you a starting reference point from which to begin your diet.
Once you know your BMR you can then determine your calorie requirements for weight maintenance, weight loss or weight gain based on your usual activity level by applying the "activity multiplier" to your BMR.
Sedentary = BMR x 1.2 (little or no exercise, desk job)
Lightly active = BMR x 1.375 (light exercise/sports 1-3 days/wk)
Mod. active = BMR x 1.55 (moderate exercise/sports 3-5 days/wk)
Very active = BMR x 1.725 (hard exercise/sports 6-7 days/wk)
Extr. active = BMR x 1.9 (hard daily exercise/sports & physical job or 2X day training, i.e marathon, contest etc.)
Note: Eating under 1,200 calories is NOT recommended. If you drop below that crucial level, it will be very hard if not impossible to get the recommended amount of vitamins and minerals. Additionally, not eating enough (less than 1,200 calories) can force your body to conserve calories by slowing down its metabolism. Always eat more than 1,200 calories unless directed otherwise by a Doctor or Dietitian. To lose weight while staying above 1,200 calories, add more physical activity into your day instead of cutting more calories.http://allnutritionals.com/