A deficit can be created by reducing input/calories consumed (lower food intake, aka dieting). A deficit can also be created by increasing output without a corresponding increase in input. Increased output is created by increasing physical activity, from increased caloric requirements necessary to heal an injury, or from growth. There are also some substances, including Caffeine, which can create a small (3-5%) increase in caloric expenditure, via a variety of pathways that include increasing physical activity levels and increasing Thermogenesis (heat output), and/or by reducing caloric input via appetite suppression. Drugs and herbal treatments creating a more extreme metabolic effect exist; however, they cause extreme increases of heart rate and thermogenesis that can cause death in even very healthy and athletic individuals, and these drugs are not widely sold.
As the calories required for energy homeostasis decreases as the organisms's mass decreases, if a moderate deficit is maintained eventually a new (lower) weight will be reached and maintained, and the organism will no longer be at caloric deficit. A permanent severe deficit, on the other hand, which contains too few calories to maintain a healthy weight level, will eventually result in starvation and death.
To reduce 1 kg of weight, about 7000 Kcal deficit is required.
- "Mayo Clinic".
- Redman, LM; Heilbronn, LK; Martin, CK; de Jonge, L; Williamson, DA; Delany, JP; Ravussin, E (February 9, 2009). "Metabolic and Behavioral Compensations in Response to Caloric Restriction: Implications for the Maintenance of Weight Loss". PLOS ONE. 4: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0004377. doi:10.1371/journal.pone.0004377. PMC . PMID 19198647.
- "Estimating Caloric Needs to Promote Wound Healing" (PDF). www.drnancycollins.com. Retrieved 2015-07-09.
- "CALORIC NEEDS". www.utmb.edu. Retrieved 2015-07-09.
- Dulloo, A. G.; Geissler, C. A.; Horton, T.; Collins, A.; Miller, D. S. (1989-01-01). "Normal caffeine consumption: influence on thermogenesis and daily energy expenditure in lean and postobese human volunteers". The American Journal of Clinical Nutrition. 49 (1): 44–50. doi:10.1093/ajcn/49.1.44. ISSN 0002-9165. PMID 2912010.
- "Acute and chronic caffeine administration increases physical activity in sedentary adults" (PDF). www.buffalo.edu. Retrieved 2015-07-09.
- "Dietary Supplements for Weight Loss — Health Professional Fact Sheet". ods.od.nih.gov. Retrieved 2015-07-09.
- Lu, Yuan-qiang; Jiang, Jiu-kun; Huang, Wei-dong (March 2011). "Clinical features and treatment in patients with acute 2,4-dinitrophenol poisoning". Journal of Zhejiang University. Science. B. 12 (3): 189–192. doi:10.1631/jzus.B1000265. ISSN 1673-1581. PMC . PMID 21370503.
- "The Effects of Starvation on Behavior: Implications for Dieting and Eating Disorders".
- Joslin, Elliott Proctor; Kahn, C. Ronald (2005-01-01). Joslin's Diabetes Mellitus: Edited by C. Ronald Kahn ... [et Al.]. Lippincott Williams & Wilkins. ISBN 9780781727969.