Let’s get scientific for a minute and talk about calories. When designing a personal nutrition plan for yourself, calculating how many calories you burn in a day is an important first step.
The number of calories you burn in a day is what’s known as your total daily energy expenditure (TDEE). Also known as your maintenance level, this number will give you a reference point for your diet.
But before we can get that number, we have to calculate your Basal Metabolic Rate (BMR). Your BMR is the energy required to maintain vital body functions, including respiration, heart rate, body temperature and blood pressure, while the body is at rest in a post-absorptive state. (That means that the digestive system is inactive, requiring about twelve hours of fasting.)
Are you still hanging in there? The good stuff is coming, I promise!
The following Harris Benedict equation is a calorie formula using the factors of height, weight, age and sex to determine your BMR. This is the minimum amount of calories you need on a daily basis.
BMR for Women = 655 + (4.35 x weight in lbs) + (4.7 x height in inches) – (4.7 x age)
BMR for Men = 66 + (6.23 x weight in lbs) + (12.7 x height in inches) – (6.8 x age)
Now that we have our BMR, we can calculate our TDEE. Simply multiply your BMR number by your activity multiplier from the chart below. This is the amount of calories you need on a daily basis to maintain your current weight.
Sedentary = BMR X 1.2 (little or no exercise, desk job)
Light activity = BMR X 1.375 (light daily exercise/sports 1-3 days/wk)
Moderate activity = BMR X 1.55 (moderate daily exercise/sports 3-5 days/wk)
High activity = BMR X 1.725 (hard daily exercise/sports 6-7 days/wk)
Very high activity = BMR X 1.9 (hard daily exercise/sports & physical job or 2X day training, i.e. marathon, contest etc.)
Whew! Do you have your number? If so, the next step is to adjust your calories to fit your goal. The idea of calorie balance is simple: to keep your weight at its current level, you should remain at your daily caloric maintenance level.
To lose weight, you need to reduce the amount of calories you eat below your maintenance level. (Adding exercise to your routine also helps this calorie deficit!) To gain weight, you need to increase your calories above your maintenance level. Whether you are trying to gain or lose weight, it’s important to maintain a balance of nutrients in your diet.
Ready for a little more math? To calculate potential weight loss, a caloric deficit of 3,500 calories is equal to one pound weight loss. So this means that if you create a 500 calorie deficit per day you will lose one pound per week. Remember, calories burned during exercise factor into this equation!
Now, these calculations for finding your correct caloric intake are just estimates to give you a starting point. You should monitor your progress to make sure that this is the proper level for you. You will know if you’re at the right level by keeping track of your caloric intake, your body weight and your body fat percentage. If you don't see the results you expect, adjust your caloric intake and exercise levels accordingly.
The bottom line is that it’s not effective to reduce calories to very low levels in order to lose fat. The best approach is to reduce calories only slightly and raise your daily calorie expenditure by increasing your frequency, duration and or intensity of exercise.
Class dismissed!
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