- Schofield Equation - October 31, 2023
- Physical Activity Level (PAL) - October 31, 2023
- BMR vs TDEE - October 30, 2023
What is TDEE?
TDEE, or Total Daily Energy Expenditure, is the amount of energy an individual uses in a day, expressed as calories used per 24 hour period. There are 3 parts to TDEE: Basal Metabolism, Thermic Effect of Food, and Physical Activity.
The 3 Energy Uses
Human energy is principally used for three functions
- Basal Metabolism (BMR) – physiological processes such as respiration
- Thermic effect of food (TEF) – the energy used to process and absorb food
- Physical activity (PA) – the energy used for physical activity
When added together, the energy used in a day for BMR, TEF, and PA equals TDEE as shown below
BMR + TEF + PA = TDEE
Why Find Your TDEE?
Once you know your TDEE you can use it to maintain your current weight or to plan weight loss or gain. It can also be used when planning macronutrient intakes. Your current TDEE is the caloric intake needed to maintain your current weight, assuming other factors remain constant.
GOAL | STRATEGIES | ACTION |
Lose weight/fat percentage | Increase TDEE and/or reduce calorie intake below TDEE | Use more energy or consume less calories |
Increase weight/fat percentage | Decrease TDEE and/or increase calorie consumption | Use less energy or consume more calories |
Keep weight/fat percentage stable | Keep TDEE stable | Continue to use the same amount of energy |
Know how many protein, fat and carbohydrate calories to consume to meet chosen dietary goals | Plan Macros based on current or increased/decreased TDEE | Consume macronutrients in the desired proportions and quantities |
*This page is a quick explanation of TDEE. Always seek expert advice when making health and diet changes.
Example of TDEE Breakdown
Example of TDEE breakdown for an individual with a TDEE of 2000 calories per day and BMR of 60% of TDEE | Calories Used per Day | Percentage of Total |
Basal Metabolism | 1200 calories | 60% |
Thermic Effect of Food | 200 calories | 10% |
Effect of Physical Activity | 600 calories | 30% |
Total Daily Energy Expenditure (TDEE) | 2000 | 100% |
Basal Metabolism
Basal Metabolism (BMR). BMR is energy use that is related to vital, on-going, physical processes such as breathing, heart function, blood circulation, and temperature regulation,(3) all of which require metabolic cell activity.(5)
BMR has traditionally been expressed as an hourly rate per kilo of body weight but here, as with other online calculators, it is calculated as a daily rate which makes it easier to apply and use in a practical way.
Basal metabolism accounts for 60-75% of daily calorie use(1) and can be measured accurately in laboratories. Alternatively, a calculator can estimate basal metabolism based on data supplied by the user.
Read more about BMR here …
Thermic Effect of Food
Thermic Effect of Food (TEF). The thermic effect of food is the energy used to process and assimilate food. It accounts for approximately 10-15% of human energy use(1) but varies between individuals based on age and activity levels as well as other factors including insulin resistance.(2)
What Does Thermic Effect of Food Mean?
When cells that are associated with food digestion and assimilation are active they produce heat, hence the term thermic effect of food. Cellular action related to food processing includes muscle contractions to move food through the digestive tract and also the creation and secretion of digestive juices.(6)
Physical Activity
Physical Activity (PA). Physical activity includes all activity performed by an individual such as general movement in daily life and work as well as intentional exercise and recreational activities.(3)
Physical activity accounts for varying percentages of total daily energy use, anywhere from 15% to 80%.(1)
Categories of Physical Activity
Energy used for physical activity includes the following:
TYPE OF PHYSICAL ACTIVITY | |
INTENTIONAL EXERCISE AND SPORT | Calories used through exercise are associated with the intensity level and the duration of the exercise |
ACTIVITY AT WORK | Movement during working hours can contribute substantially to the total amount of daily energy used |
RECREATIONAL ACTIVITIES | Includes leisure activities such as reading, gardening, golf |
HOUSEWORK & DAILY TASKS | Includes physical housework and cleaning, running errands, yardwork |
INCIDENTAL MOVEMENT | Includes fidgeting and pacing and other movements we may not be aware of |
Differences Between Individuals in Their Energy Usage
There are differences between people in their energy use but the biggest variation, by far, is associated with physical activity.(2)
TYPE OF ENERGY USE | DIFFERENCES BETWEEN PEOPLE |
BASAL METABOLIC RATE | Some differences |
THERMIC EFFECT OF FOOD | Some differences |
PHYSICAL ACTIVITY | LARGE differences between people |
TOTAL DAILY ENERGY EXPENDITURE | LARGE differences between people |
Abbreviations
Note: Sometimes authors use different abbreviations and terms in relation to metabolism when they mean the same thing. Conversely, terms are sometimes used interchangeably even when they have slightly different meanings.
AT – Activity Thermogenesis – The energy cost of physical activity. Same meaning as PA (Physical Activity)
BMR – Basal Metabolic Rate – The number of calories used in a day when at rest and not active or digesting
NEAT – Non-Exercise Activity Thermogenesis – All physical activity other than intentional sport and exercise
NREE = Non Resting Energy Expenditure. A metabolic value representing the thermic effect of food and physical activity (TEF + PA)
PA – Physical Activity – The energy cost of physical activity, both intentional and non-intentional
PAEE – Physical Activity Energy Expenditure – same as PA
SPA – Spontaneous Physical Activity(3)
TDEE/ TEE – Total Daily Energy Expenditure – The number of calories used per day
TEF – Thermic Effect of Food – The energy cost of processing and assimilating food
References
- Barbara Bushman (Editor). Complete Guide to Fitness and Health (2nd edition) ISBN 9781492533672
- Peter Raven, David Wasserman, William Squires, Tinker Murray, Exercise Physiology: An Integrated Approach (International Edition)
ISBN 9780538735469 - Yan Y. Lam and Eric Ravussin. Analysis of Energy Metabolism in Humans: A Review of Methodologies. http://dx.doi.org/10.1016/j.molmet.2016.09.005
- James A. Levine, Mark W. Vander Weg, James O. Hill and Robert C. Klesges. Non-Exercise Activity Thermogenesis: The Crouching tiger Hidden Dragon of Societal Weight Gain. DOI: 10.1161/01.ATV.0000205848.83210.73
- A. Catherine Ross et al. (Editors). Modern Nutrition in Health and Disease (11th Edition) ISBN 9781605474618
- Linda Debruyne and Kathryn Pinna. Nutrition for Health and Care (7th Edition) ISBN 9780357022467
- Sabounchi NS, Rahmandad H, Ammerman A. Best-fitting prediction equations for basal metabolic rate: informing obesity interventions in diverse populations. Int J Obes (Lond). 2013 Oct;37(10):1364-70. doi: 10.1038/ijo.2012.218. Epub 2013 Jan 15. PMID: 23318720; PMCID: PMID 23318720
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- Harris J, Benedict F (1918). “A Biometric Study of Human Basal Metabolism”. PMID 16576330.
- Roza AM, Shizgal HM (1984). “The Harris Benedict equation reevaluated. The American Journal of Clinical Nutrition. PMID 6741850
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO (1990). “A new predictive equation for resting energy expenditure in healthy individuals”. The American Journal of Clinical Nutrition. PMID 2305711.
- Owen OE, Holup JL, D’Alessio DA, Craig ES, Polansky M, Smalley KJ, Kavle EC, Bushman MC, Owen LR, Mozzoli MA. et al.A reappraisal of the caloric requirements of men. Am J Clin Nutr. 1987;46:875″885. [PubMed]
- 17. Liu HY, Lu YF, Chen WJ. Predictive equations for basal metabolic rate in Chinese adults: a cross-validation study. J Am Diet Assoc. 1995;95:1403″1408. doi: 10.1016/S0002-8223(95)00369-X. [PubMed]
- FAO/WHO/UNU. Energy and Protein Requirements. Geneva: World Health Organisation; 1985. [Google Scholar]
Extra Reading
- Kansas State University. “Physical Activity and Controlling Weight,” (accessed March 30, 2019), https://www.k-state.edu/
- Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc. 2005;105:775″789. doi: 10.1016/j.jada.2005.02.005. [PubMed]