Energy expenditure explained

Energy expenditure, often estimated as the total daily energy expenditure (TDEE), is the amount of energy burned by the human body.

Causes of energy expenditure

Resting metabolic rate

See main article: Resting metabolic rate. Resting metabolic rate generally composes 60 to 75 percent of TDEE. Because adipose tissue does not use much energy to maintain, fat free mass is a better predictor of metabolic rate. A taller person will typically have less fat mass than a shorter person at the same weight and therefore burn more energy. Men also carry more skeletal muscle tissue on average than women, and other sex differences in organ size account for sex differences in metabolic rate. Obese individuals burn more energy than lean individuals due to increase in the amount of calories needed to maintain adipose tissue and other organs that grow in size in response to obesity. At rest, the largest fractions of energy are burned by the skeletal muscles, brain, and liver; around 20 percent each.[1] Increasing skeletal muscle tissue can increase metabolic rate.

Activity

Energy burned during physical activity includes the exercise activity thermogenesis (EAT) and non-exercise activity thermogenesis (NEAT).[2]

Thermic effect of food

See main article: Thermic effect of food. Thermic effect of food is the amount of energy burned digesting food, around 10 percent of TDEE. Proteins are the component of food requiring the most energy to digest.[3]

Changing energy expenditure

Weight change

Losing or gaining weight affects the energy expenditure. Reduced energy expenditure after weight loss can be a major challenge for people seeking to avoid weight regain after weight loss.[4] It is controversial whether losing weight causes a decrease in energy expenditure greater than expected by the loss of adipose tissue and fat-free mass during weight loss.[5] This excess reduction is termed adaptive thermogenesis and it is estimated that it might compose 50 to 100 kcal/day in people actively losing weight. Some studies have reported that it disappears after a short period of weight stability, while others report longer-lasting effects.[1]

Changing the activity level

Increasing exercise is recommended as a way to increase energy expenditure in individuals seeking to lose weight.[6] [7]

Drugs

Some drugs used for weight loss work by increasing energy expenditure. Two of the earliest weight loss drugs, 2,4-dinitrophenol and thyroid hormone, increase energy expenditure, but both were withdrawn from use due to risks.[8] Adrenergic agonists, especially those that work on the beta-2 adrenergic receptor, increase energy expenditure. Although some such as clenbuterol are used without medical approval for weight loss, none have achieved approval for this indication due to cardiac risks.[8] [9]

Other drugs such as atypical antipsychotics are believed to reduce energy expenditure.[10] [11]

Effects

Energy expenditure is a leading factor in regulating appetite and energy intake in humans.[12]

Measurement

Formulas have been devised to estimate energy expenditure in humans, but they may not be accurate for people with certain illnesses[13] [14] [15] or the elderly.[16] Not all formula are accurate in overweight or obese individuals.[17]

Wearable devices can help estimate energy expenditure from physical activity but their accuracy varies.[18]

Notes and References

  1. Heymsfield . Steven B. . Smith . Brooke . Dahle . Jared . Kennedy . Samantha . Fearnbach . Nicole . Thomas . Diana M. . Bosy‐Westphal . Anja . Müller . Manfred J. . Resting Energy Expenditure: From Cellular to Whole‐Body Level, a Mechanistic Historical Perspective . Obesity . March 2021 . 29 . 3 . 500–511 . 10.1002/oby.23090. 33624441 . 232021492 .
  2. Web site: Comana . Fabio . Resting Metabolic Rate: How to Calculate and Improve Yours . blog.nasm.org . 15 October 2023 . en.
  3. Web site: Energy Balance: Totaling Up Energy Expenditure . Obesity Prevention Source . 15 October 2023 . en-us . 21 October 2012.
  4. Müller . Manfred J. . Enderle . Janna . Bosy-Westphal . Anja . Changes in Energy Expenditure with Weight Gain and Weight Loss in Humans . Current Obesity Reports . 1 December 2016 . 5 . 4 . 413–423 . 10.1007/s13679-016-0237-4 . 27739007 . 5097076 . en . 2162-4968. free .
  5. Schwartz . Alexander . Kuk . Jennifer L. . Lamothe . Gilles . Doucet . Éric . Greater Than Predicted Decrease in Resting Energy Expenditure and Weight Loss: Results From a Systematic Review . Obesity . November 2012 . 20 . 11 . 2307–2310 . 10.1038/oby.2012.34. 22327054 . free .
  6. Washburn . R. A. . Lambourne . K. . Szabo . A. N. . Herrmann . S. D. . Honas . J. J. . Donnelly . J. E. . Does increased prescribed exercise alter non‐exercise physical activity/energy expenditure in healthy adults? A systematic review . Clinical Obesity . February 2014 . 4 . 1 . 1–20 . 10.1111/cob.12040 . 25425128 . 5996763 . en . 1758-8103. free .
  7. Wiklund . Petri . The role of physical activity and exercise in obesity and weight management: Time for critical appraisal . Journal of Sport and Health Science . June 2016 . 5 . 2 . 151–154 . 10.1016/j.jshs.2016.04.001. 30356545 . free . 6188737 .
  8. Christoffersen . Berit Østergaard . Sanchez‐Delgado . Guillermo . John . Linu Mary . Ryan . Donna H. . Raun . Kirsten . Ravussin . Eric . Beyond appetite regulation: Targeting energy expenditure, fat oxidation, and lean mass preservation for sustainable weight loss . Obesity . April 2022 . 30 . 4 . 841–857 . 10.1002/oby.23374 . 35333444 . en . 1930-7381. 9310705 .
  9. Kumari . Sweta . Pal . Biplab . Sahu . Sanjeev Kumar . Prabhakar . Pranav Kumar . Tewari . Devesh . Adverse events of clenbuterol among athletes: a systematic review of case reports and case series . International Journal of Legal Medicine . 1 July 2023 . 137 . 4 . 1023–1037 . 10.1007/s00414-023-02996-1 . 37062796 . 258178293 . en . 1437-1596.
  10. Singh . Raghunath . Bansal . Yashika . Medhi . Bikash . Kuhad . Anurag . Antipsychotics-induced metabolic alterations: Recounting the mechanistic insights, therapeutic targets and pharmacological alternatives . European Journal of Pharmacology . February 2019 . 844 . 231–240 . 10.1016/j.ejphar.2018.12.003. 30529195 . 54482216 .
  11. Cuerda . C. . Velasco . C. . Merchán-Naranjo . J. . García-Peris . P. . Arango . C. . The effects of second-generation antipsychotics on food intake, resting energy expenditure and physical activity . European Journal of Clinical Nutrition . February 2014 . 68 . 2 . 146–152 . 10.1038/ejcn.2013.253 . 24327118 . en . 1476-5640. free .
  12. Blundell . John E . Gibbons . Catherine . Beaulieu . Kristine . Casanova . Nuno . Duarte . Cristiana . Finlayson . Graham . Stubbs . R James . Hopkins . Mark . The drive to eat in homo sapiens: Energy expenditure drives energy intake . Physiology & Behavior . May 2020 . 219 . 112846 . 10.1016/j.physbeh.2020.112846. 32081814 . 211141215 .
  13. Mazzo . Rafaela . Ribeiro . Francieli Barreiro . Vasques . Ana Carolina Junqueira . Accuracy of predictive equations versus indirect calorimetry for the evaluation of energy expenditure in cancer patients with solid tumors – An integrative systematic review study . Clinical Nutrition ESPEN . February 2020 . 35 . 12–19 . 10.1016/j.clnesp.2019.11.001 . 31987104 . 210935787 . en.
  14. Genton . L. . Viatte . V. . Janssens . J. -P. . Héritier . A. -C. . Pichard . C. . Nutritional state, energy intakes and energy expenditure of amyotrophic lateral sclerosis (ALS) patients . Clinical Nutrition . 1 October 2011 . 30 . 5 . 553–559 . 10.1016/j.clnu.2011.06.004 . 21798636 . 0261-5614.
  15. Santos . Bárbara Chaves . Correia . Maria Isabel Toulson Davisson . Anastácio . Lucilene Rezende . Energy Expenditure and Liver Transplantation: What We Know and Where We Are . Journal of Parenteral and Enteral Nutrition . March 2021 . 45 . 3 . 456–464 . 10.1002/jpen.1985. 32744332 . free . 1843/40766 . free .
  16. Cioffi . Iolanda . Marra . Maurizio . Pasanisi . Fabrizio . Scalfi . Luca . Prediction of resting energy expenditure in healthy older adults: A systematic review . Clinical Nutrition . May 2021 . 40 . 5 . 3094–3103 . 10.1016/j.clnu.2020.11.027. 33288302 . free . 2434/953871 . free .
  17. Macena . Mateus de Lima . Paula . Déborah Tenório da Costa . da Silva Júnior . André Eduardo . Praxedes . Dafiny Rodrigues Silva . Pureza . Isabele Rejane de Oliveira Maranhão . de Melo . Ingrid Sofia Vieira . Bueno . Nassib Bezerra . Estimates of resting energy expenditure and total energy expenditure using predictive equations in adults with overweight and obesity: a systematic review with meta-analysis . Nutrition Reviews . 10 October 2022 . 80 . 11 . 2113–2135 . 10.1093/nutrit/nuac031 . 35551409 . free .
  18. O’Driscoll . Ruairi . Turicchi . Jake . Beaulieu . Kristine . Scott . Sarah . Matu . Jamie . Deighton . Kevin . Finlayson . Graham . Stubbs . James . How well do activity monitors estimate energy expenditure? A systematic review and meta-analysis of the validity of current technologies . British Journal of Sports Medicine . 1 March 2020 . 54 . 6 . 332–340 . 10.1136/bjsports-2018-099643 . 30194221 . en . 0306-3674. free .