If an individual consumes more calories than their total daily energy expenditure (TDEE), they are in in a positive energy balance. This is necessary during times of growth such as in infancy, child and pregnancy. Otherwise, a positive energy balance results in weight gain. When more calories are expended than consumed an individual is in negative energy balance, which is necessary for weight loss.
TDEE is also known as your maintenance level because this is the amount of energy (calories) you require to maintain your body weight. If you eat less than your TDEE, you will lose weight.
If you eat equal to your TDEE, you will maintain your weight, and if you eat more than your TDEE, you will gain weight. TDEE is calculated by multiplying your BMR by your activity factor.
Your basal metabolic rate (BMR) is the total amount of energy (calories) your body requires daily just to maintain normal bodily functions, including digestion, circulation, respiration, temperature regulation, cell construction and every other process in your body. BMR is the total of all the energy you use for basic bodily functions, not including physical activity.
So, to address weight loss goals, it is suggested to start by estimating your TDEE. Fortunately, links to our online calorie calculators are provided below and there is no need to try to calculate your TDEE manually using the formulas below unless you just want to.
Katch McArdle Calorie Calculator
The Katch McArdle formula takes into account lean body mass, which allows you to obtain a very precise estimate of your basal metabolic rate. This formula tends to be slightly more accurate than other formulas which are based on total body weight, especially for individuals on the extremes such as very high or very low body fat. However, you must know your lean body mass (LBM). If you are in the HIIT Transformation program generally LBM will be provided that for you. Otherwise, you would need to calculate it yourself or have a fitness / health professional do it for you.
The Katch McArdle formula calculates basal metabolic rate for both men and women (it’s a “unisex formula).
The Katch McArdle Calorie Calculator lets you choose your own personal activity level. This customizes your daily caloric maintenance level (TDEE).
Mifflin-St. Jeor Formula
If you do not know your LMB there are other methods like the Mifflin-St. Jeor formula which also provides a fairly accurate estimation of BMR and TDEE. If you are really motivated you can manually calculate these values using the Mifflin-St. Jeor formula below.
Keep in mind that the estimations from the calculators are only a start point. Actual caloric needs will vary based on the unique demands of each individual.
Calculating Your Daily Macros
The information below is based on the daily macro nutrient and caloric needs of an inherently healthy, active individual without contraindications or significant health problems and one who answered ‘No’ to all the questions in our HIIT Transformation Readiness Questionnaire.
When considering your Macro-nutrient balance remember:
1gram of carbohydrates = 4 calories
1gram of protein = 4 calories
1gram of fat = 9 calories
Assuming my body fat percentage is 7%, my weight is 170 pounds and my age is 41 then my LBM is about 158 pounds. This information is provided to those in the HIIT Transformation program. Putting this information into the Katch McArdle calculator and a moderate activity 3~5 days per week I need 2582 calories per day.
As I mentioned in the Pre & Post Workout Nutrition blog, due to leading a very active lifestyle and the need to keep glycogen stores I eat a macro balance similar to 10~35% protein, 45~65% carbohydrate, and 15~35% fat. This is the recommendation of several leading fitness and dietary organizations. In fact, I try to maintain around 25% protein, 60% carbohydrate and 15% fat although it varies from day to day based on my anticipated activity level for the day. However, these percentages will be the used to determine my macro balance below as an example.
25% Protein = 2582 cal x 25% = 645 cal/(4cal/g) = 161g
60% Carbohydrate = 2582 cal x 60% = 1549 cal/(4cal/g) = 387g
15% Fat = 2582 cal x 15% = 387 cal/(4cal/g) = 97g
Simply put, to lose 1lb of fat, create a 3,500-calorie deficit. Example: Eat 250 calories less per day and expend 250 calories more per day (create a 500 calorie deficit) through daily activity over 7 days to lose 1lb of fat per week. Generally, any loss greater than 1~2 lbs per week is not fat loss. It is also very possible to gain 1~2 lbs of lean body mass per week with proper exercise and caloric intake. The 3,500 calorie target is based on the approximate number of calories in 1 lb of body fat.
Why 3,500 Calories?
The 3,500 calories is calculated like this: 454g in 1 Pound 1 Gram of Fat = 9 calories. 9 calories x 454g = 4,086 calories. 87% of the fat mass is actual lipid so, 87% x 4,086 calories = 3,552 calories. However, the more fat mass a person has the more readily they will loss fat mass. The main point is that in order to loose weight or more importantly to loose fat mass a person must create a calorie deficit. The actual fat mass lost will vary from person to person based on each individuals unique set of circumstances.
Just HIIT It!
Coach Tim Garrett
Mifflin-St. Jeor Formula (BMR)
For men: BMR = [9.99 x wt (kg} + 6.25 x ht (cm) – 4.92 x age (yrs) + 5)] kcal/day
For women: BMR = [9.99x wt (kg) + 6.25x ht (cm) – 4.92 x age (yrs) – 161] kcal/day
Note: Convert pounds to kilograms by dividing by 2.2; convert inches to centimeters by multiplying by 2.54
Note: 1 kg= 2.2 lb; l inch = 2.54 cm
The Katch-McArdle Formula (BMR)
BMR = 370 + (9.7976 x LBM) kcal/day, where LBM is lean body mass in pounds.
Activity Correction Factor
The BMR derived from these equations is then multiplied by the appropriate activity correction factor to determine TDEE.
Sedentary (little or no exercise): 1.200
Lightly active (light exercise/sports one to three days per week): 1.375
Moderately active (moderate exercise/sports six to seven days per week): 1.550
Very active (hard exercise/sports six to seven days per week): 1.725
Extra active (very hard exercise/sports and a physical job): 1.900