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{{short description|Dietary regime}}
{{For|caloric restriction for the purpose of weight loss|dieting}}
'''Calorie restriction''' ('''CR''', also known as '''caloric restriction''' or '''energy restriction''') is a [[Diet (nutrition)|dietary regimen]] that [[Calorie deficit|reduces the energy intake]] from foods and beverages without incurring [[malnutrition]].<ref name="lee">{{Cite journal |vauthors=Lee MB, Hill CM, Bitto A, Kaeberlein M |date=November 2021 |title=Antiaging diets: Separating fact from fiction |journal=Science |volume=374 |issue=6570 |pages=eabe7365 |doi=10.1126/science.abe7365 |pmc=8841109 |pmid=34793210}}</ref><ref>{{Cite journal |vauthors=Flanagan EW, Most J, Mey JT, Redman LM |date=September 2020 |title=Calorie Restriction and Aging in Humans |journal=Annual Review of Nutrition |volume=40 |pages=105–133 |doi=10.1146/annurev-nutr-122319-034601 |pmc=9042193 |pmid=32559388}}</ref> The possible effect of calorie restriction on [[Human body weight|body weight management]], [[diet and longevity|longevity]], and [[aging-associated disease]]s has been an active area of research.<ref name=lee/>

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==Dietary guidelines==

Caloric intake control, and reduction for [[obesity|overweight]] individuals, is recommended by US dietary guidelines and science-based societies.<ref name="USDietaryGuidelines2015">{{Cite web |last=US Department of Health and Human Services. |date=2017 |title=2015–2020 Dietary Guidelines for Americans - health.gov |url=https://health.gov/dietaryguidelines/2015/ |access-date=30 September 2019 |website=health.gov |publisher=Skyhorse Publishing Inc.}}</ref><ref name="AACAHA2019">{{Cite journal |display-authors=6 |vauthors=Arnett DK, Blumenthal RS, Albert MA, Buroker AB, Goldberger ZD, Hahn EJ, Himmelfarb CD, Khera A, Lloyd-Jones D, McEvoy JW, Michos ED, Miedema MD, Muñoz D, Smith SC, Virani SS, Williams KA, Yeboah J, Ziaeian B |date=September 2019 |title=2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines |journal=Circulation |volume=140 |issue=11 |pages=e596–e646 |doi=10.1161/CIR.0000000000000678 |pmc=7734661 |pmid=30879355 |doi-access=free}}</ref><ref name="NICE2019-obesity">{{Cite web |title=Obesity: maintaining a healthy weight and preventing excess weight gain |url=https://pathways.nice.org.uk/pathways/obesity/obesity-maintaining-a-healthy-weight-and-preventing-excess-weight-gain#content=view-node%3Anodes-diet |website=pathways.nice.org.uk}}</ref><ref name="USGuidelines2013">{{Cite journal |display-authors=6 |vauthors=Jensen MD, Ryan DH, Apovian CM, Ard JD, Comuzzie AG, Donato KA, Hu FB, Hubbard VS, Jakicic JM, Kushner RF, Loria CM, Millen BE, Nonas CA, Pi-Sunyer FX, Stevens J, Stevens VJ, Wadden TA, Wolfe BM, Yanovski SZ, Jordan HS, Kendall KA, Lux LJ, Mentor-Marcel R, Morgan LC, Trisolini MG, Wnek J, Anderson JL, Halperin JL, Albert NM, Bozkurt B, Brindis RG, Curtis LH, DeMets D, Hochman JS, Kovacs RJ, Ohman EM, Pressler SJ, Sellke FW, Shen WK, Smith SC, Tomaselli GF |date=June 2014 |title=2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society |journal=Circulation |volume=129 |issue=25 Suppl 2 |pages=S102–S138 |doi=10.1161/01.cir.0000437739.71477.ee |pmc=5819889 |pmid=24222017}}</ref><ref name="NICE2019">{{Cite web |title=Diet - NICE Pathways |url=https://pathways.nice.org.uk/pathways/diet#path=view%3A/pathways/diet/dietary-interventions-and-advice-for-adults.xml&content=view-node%3Anodes-reducing-calorie-intake |website=pathways.nice.org.uk}}</ref><ref name="Garvey2016">{{Cite journal |display-authors=6 |vauthors=Garvey WT, Mechanick JI, Brett EM, Garber AJ, Hurley DL, Jastreboff AM, Nadolsky K, Pessah-Pollack R, Plodkowski R |date=July 2016 |title=American Association of Clinical Endocrinologists and American College of Endocrinology Comprehensive Clinical Practice Guidelines for Medical Care of Patients with Obesity |journal=Endocrine Practice |volume=22 |issue=Suppl 3 |pages=1–203 |doi=10.4158/EP161365.GL |pmid=27219496 |doi-access=free}}</ref>

Calorie restriction is recommended for people with [[diabetes]]<ref name="ADA2019">{{Cite journal |last=American Diabetes Association |date=January 2019 |title=5. Lifestyle Management: ''Standards of Medical Care in Diabetes-2019'' |journal=Diabetes Care |volume=42 |issue=Suppl 1 |pages=S46–S60 |doi=10.2337/dc19-S005 |pmid=30559231 |doi-access=free}}</ref><ref name="ADA2018">{{Cite journal |display-authors=6 |vauthors=Evert AB, Dennison M, Gardner CD, Garvey WT, Lau KH, MacLeod J, Mitri J, Pereira RF, Rawlings K, Robinson S, Saslow L, Uelmen S, Urbanski PB, Yancy WS |date=May 2019 |title=Nutrition Therapy for Adults With Diabetes or Prediabetes: A Consensus Report |journal=Diabetes Care |type=Professional society guidelines |volume=42 |issue=5 |pages=731–754 |doi=10.2337/dci19-0014 |pmc=7011201 |pmid=31000505 |doi-access=free}}</ref> and prediabetes,<ref name="ADA2018" /> in combination with physical exercise and a weight loss goal of 5-15% for diabetes and 7-10% for prediabetes to prevent progression to diabetes.<ref name="ADA2018" /> Mild calorie restriction may be beneficial for pregnant women to reduce weight gain (without weight loss) and reduce perinatal risks for both the mother and child.<ref name="Glazier2018">{{Cite journal |vauthors=Glazier JD, Hayes DJ, Hussain S, D'Souza SW, Whitcombe J, Heazell AE, Ashton N |date=October 2018 |title=The effect of Ramadan fasting during pregnancy on perinatal outcomes: a systematic review and meta-analysis |journal=BMC Pregnancy and Childbirth |volume=18 |issue=1 |pages=421 |doi=10.1186/s12884-018-2048-y |pmc=6202808 |pmid=30359228 |doi-access=free}}</ref><ref name="Than2012">{{Cite journal |display-authors=6 |vauthors=Thangaratinam S, Rogozinska E, Jolly K, Glinkowski S, Roseboom T, Tomlinson JW, Kunz R, Mol BW, Coomarasamy A, Khan KS |date=May 2012 |title=Effects of interventions in pregnancy on maternal weight and obstetric outcomes: meta-analysis of randomised evidence |journal=BMJ |volume=344 |pages=e2088 |doi=10.1136/bmj.e2088 |pmc=3355191 |pmid=22596383}}</ref> For [[management of obesity|overweight or obese]] individuals, calorie restriction may improve health through weight loss, although a gradual weight regain of {{convert|1|-|2|kg|abbr=on}} per year may occur.<ref name="AACAHA2019" /><ref name="USGuidelines2013" />

===Risks of malnutrition===
The term "calorie restriction" as used in [[gerontology|the study of aging]] refers to dietary regimens that reduce calorie intake without incurring [[malnutrition]].<ref name=lee/> If a restricted diet is not designed to include essential nutrients, malnutrition may result in serious deleterious effects, as shown in the [[Minnesota Starvation Experiment]].<ref name="Keys A 1950" /> This study was conducted during [[World War II]] on a group of lean men, who restricted their calorie intake by 45%<ref>Keys A 1950, p. 114.</ref> for six months and composed roughly 77% of their diet with carbohydrates.<ref name="Keys A 1950">Keys A, Brozek J, Henschels A & Mickelsen O & Taylor H. The Biology of Human Starvation, 1950. University of Minnesota Press, Minneapolis</ref> As expected, this malnutrition resulted in [[Starvation response|metabolic adaptations]], such as decreased body fat, improved lipid profile, and decreased resting heart rate. The experiment also caused negative effects, such as [[anemia]], [[edema]], [[Muscle atrophy|muscle wasting]], [[weakness]], [[dizziness]], [[irritability]], [[lethargy]], and depression.<ref name="Keys A 1950" />

Typical low-calorie diets may not supply sufficient nutrient intake that is typically included in a calorie restriction diet.<ref name="St. Jeor et al, 2001">{{Cite journal |vauthors=St Jeor ST, Howard BV, Prewitt TE, Bovee V, Bazzarre T, Eckel RH |date=October 2001 |title=Dietary protein and weight reduction: a statement for healthcare professionals from the Nutrition Committee of the Council on Nutrition, Physical Activity, and Metabolism of the American Heart Association |journal=Circulation |volume=104 |issue=15 |pages=1869–1874 |doi=10.1161/hc4001.096152 |pmid=11591629 |doi-access=free}}</ref><ref name="de Souza et al, 2008">{{Cite journal |vauthors=de Souza RJ, Swain JF, Appel LJ, Sacks FM |date=July 2008 |title=Alternatives for macronutrient intake and chronic disease: a comparison of the OmniHeart diets with popular diets and with dietary recommendations |journal=The American Journal of Clinical Nutrition |volume=88 |issue=1 |pages=1–11 |doi=10.1093/ajcn/88.1.1 |pmc=2674146 |pmid=18614716}}</ref><ref name="Ma et al, 2007">{{Cite journal |vauthors=Ma Y, Pagoto SL, Griffith JA, Merriam PA, Ockene IS, Hafner AR, Olendzki BC |date=October 2007 |title=A dietary quality comparison of popular weight-loss plans |journal=Journal of the American Dietetic Association |volume=107 |issue=10 |pages=1786–1791 |doi=10.1016/j.jada.2007.07.013 |pmc=2040023 |pmid=17904938}}</ref>

===Possible side effects===
People losing weight during calorie restriction risk developing [[side effect]]s, such as [[cold sensitivity]], [[menstrual irregularities]], [[infertility]], or hormonal changes.<ref>{{Cite journal |vauthors=Marzetti E, Wohlgemuth SE, Anton SD, Bernabei R, Carter CS, Leeuwenburgh C |date=November 2009 |title=Cellular mechanisms of cardioprotection by calorie restriction: state of the science and future perspectives |journal=Clinics in Geriatric Medicine |volume=25 |issue=4 |pages=715–32, ix |doi=10.1016/j.cger.2009.07.002 |pmc=2786899 |pmid=19944269}}</ref>

==Research==

===Humans===
Decreasing [[Food energy#Recommended daily intake|caloric intake]] by 20-30%, while fulfilling nutrient requirements, has been found to remedy diseases of aging, including cancer, cardiovascular disease, dementia, and diabetes in humans, and result in an average loss of {{convert|7.9|kg|lbs}} in body weight, but because of the long lifespan of humans, evidence that calorie restriction could prevent age-related disease in humans remains under preliminary research.<ref name=lee/><ref>{{Cite journal |display-authors=6 |vauthors=Caristia S, Vito M, Sarro A, Leone A, Pecere A, Zibetti A, Filigheddu N, Zeppegno P, Prodam F, Faggiano F, Marzullo P |date=July 2020 |title=Is Caloric Restriction Associated with Better Healthy Aging Outcomes? A Systematic Review and Meta-Analysis of Randomized Controlled Trials |journal=Nutrients |volume=12 |issue=8 |page=2290 |doi=10.3390/nu12082290 |pmc=7468870 |pmid=32751664 |doi-access=free}}</ref> While calorie restriction leads to weight and fat loss, the precise amount of calorie intake and associated fat mass for optimal health in humans is not known.<ref name=lee/> Moderate amounts of calorie restriction may have harmful effects on certain population groups, such as lean people with low body fat.<ref name=lee/>

===Life extension===
As of 2021, [[intermittent fasting]] and calorie restriction remain under preliminary research to assess the possible effects on disease burden and increased lifespan during aging, although the relative risks associated with long-term fasting or calorie restriction remain undetermined.<ref name=lee/>

Intermittent fasting refers to periods with intervals during which no food but only clear fluids are ingested – such as a period of daily time-restricted eating with a window of 8 to 12 hours for any caloric intake – and could be combined with overall calorie restriction and variants of the [[Mediterranean diet]] which may contribute to long-term cardiovascular health and longevity.<ref>{{Cite journal |vauthors=O'Keefe JH, Torres-Acosta N, O'Keefe EL, Saeed IM, Lavie CJ, Smith SE, Ros E |date=September 2020 |title=A pesco-Mediterranean diet with intermittent fasting: JACC Review Topic of the Week |journal=Journal of the American College of Cardiology |volume=76 |issue=12 |pages=1484–1493 |doi=10.1016/j.jacc.2020.07.049 |pmid=32943166 |s2cid=221787788 |doi-access=free}}</ref>

===Minnesota Starvation Experiment===
The [[Minnesota Starvation Experiment]] examined the physical and psychological effects of extreme calorie restriction on 32 young and lean 24-year-old men during a 40% reduction in energy intake for 6 months. The study was designed to mimic dietary conditions during World War II. Participants could only eat 1800 kcal per day, but were required to walk 5 km per day and expend 3000 [[calorie]]s.<ref name=":1">{{Cite journal |vauthors=Most J, Tosti V, Redman LM, Fontana L |date=October 2017 |title=Calorie restriction in humans: An update |journal=Ageing Research Reviews |series=Nutritional interventions modulating aging and age-associated diseases |volume=39 |pages=36–45 |doi=10.1016/j.arr.2016.08.005 |pmc=5315691 |pmid=27544442}}</ref> The men lost about 25% of their body weight of which 67% was fat mass and 17% fat-free mass.<ref name=":1" /> The quality of the diet was insufficient, as it was intended to accurately represent the diet during war due to the inadequate consumption of protein, and a lack of fruits and vegetables. Despite the extreme calorie restriction, the experiment was not representative of true calorie-restrictive diets, which adhere to intake guidelines for [[macronutrient]]s and [[micronutrient]]s.<ref name=":1" /> Chronic weakness, decreased aerobic capacity, and painful lower limb edema was caused by the malnourished calorie restrictive diet.<ref name=":1" /><ref>{{Cite book |title=The biology of human starvation (2 vols). |vauthors=Keys A, Brožek J, Henschel A, Mickelsen O, Taylor HL |publisher=Univ. of Minnesota Press |year=1950}}</ref> Emotional distress, confusion, [[apathy]], depression, [[hysteria]], [[hypochondriasis]], suicidal thoughts, and loss of sex drive were among the abnormal psychological behaviors that occurred within six weeks.<ref name=":1" />

===Intensive care===
{{Asof|2019}}, current clinical guidelines recommend that hospitals ensure that the patients get fed with 80–100% of energy expenditure, the normocaloric feeding. A systematic review investigated whether people in [[intensive care unit]]s have different outcomes with normocaloric feeding or hypocaloric feeding, and found no difference.<ref>{{Cite journal |vauthors=Marik PE, Hooper MH |date=March 2016 |title=Normocaloric versus hypocaloric feeding on the outcomes of ICU patients: a systematic review and meta-analysis |journal=Intensive Care Medicine |volume=42 |issue=3 |pages=316–323 |doi=10.1007/s00134-015-4131-4 |pmid=26556615 |s2cid=37653149}}</ref> However, a comment criticized the inadequate control of protein intake, and raised concerns that hypocaloric feeding safety should be further assessed with underweight critically ill people.<ref>{{Cite journal |vauthors=Bitzani M |date=April 2016 |title=Comments on Marik and Hooper: Normocaloric versus hypocaloric feeding on the outcomes of ICU patients: a systematic review and meta-analysis |journal=Intensive Care Medicine |volume=42 |issue=4 |pages=628–629 |doi=10.1007/s00134-016-4248-0 |pmid=26880090 |s2cid=34072936}}</ref>

===Non-human primates===
A calorie restriction study started in 1987 by the [[National Institute on Aging]] showed that calorie restriction did not extend years of life or reduce age-related deaths in non-obese [[rhesus macaque]]s.<ref name="NIA2012">{{Cite web |last=[[National Institutes of Health]] |date=2012-08-29 |title=NIH study finds calorie restriction does not affect survival |url=https://www.nih.gov/news-events/news-releases/nih-study-finds-calorie-restriction-does-not-affect-survival |access-date=May 17, 2016}}</ref> It did improve certain measures of health, however.<ref name="NYTimes2014">{{Cite web |last=Nicholas Wade |date=April 1, 2014 |title=Diet's Link to Longevity: After 2 Studies Diverge, a Search for Consensus |url=https://www.nytimes.com/2014/04/02/science/a-new-salvo-in-debate-over-caloric-restrictions-and-longevity.html |access-date=May 17, 2016 |newspaper=The New York Times}}</ref> These results were publicized as being different from the Wisconsin rhesus macaque calorie restriction study, which also started in 1987 and showed an increase in the lifespan of rhesus macaques following calorie restriction.<ref name="NIA2012" />

In a 2017 report on rhesus monkeys, caloric restriction in the presence of adequate nutrition was effective in delaying the effects of aging.<ref name="Mattison2017">{{Cite journal |display-authors=6 |vauthors=Mattison JA, Colman RJ, Beasley TM, Allison DB, Kemnitz JW, Roth GS, Ingram DK, Weindruch R, de Cabo R, Anderson RM |date=January 2017 |title=Caloric restriction improves health and survival of rhesus monkeys |journal=Nature Communications |volume=8 |issue=1 |pages=14063 |bibcode=2017NatCo...814063M |doi=10.1038/ncomms14063 |pmc=5247583 |pmid=28094793}}</ref><ref name="sd">{{Cite press release |title=Calorie restriction lets monkeys live long and prosper |date=17 January 2017 |publisher=University of Wisconsin-Madison |url=https://www.sciencedaily.com/releases/2017/01/170117140105.htm |work=ScienceDaily}}</ref> Older age of onset, female sex, lower body weight and fat mass, reduced food intake, diet quality, and lower [[fasting]] [[blood glucose]] levels were factors associated with fewer disorders of aging and with improved survival rates.<ref name=Mattison2017/> Specifically, reduced food intake was beneficial in adult and older primates, but not in younger monkeys.<ref name=Mattison2017/> The study indicated that caloric restriction provided health benefits with fewer age-related disorders in elderly monkeys and, because rhesus monkeys are genetically similar to humans, the benefits and mechanisms of caloric restriction may apply to human health during aging.<ref name="Mattison">{{Cite journal |display-authors=6 |vauthors=Mattison JA, Roth GS, Beasley TM, Tilmont EM, Handy AM, Herbert RL, Longo DL, Allison DB, Young JE, Bryant M, Barnard D, Ward WF, Qi W, Ingram DK, de Cabo R |date=September 2012 |title=Impact of caloric restriction on health and survival in rhesus monkeys from the NIA study |journal=Nature |volume=489 |issue=7415 |pages=318–321 |bibcode=2012Natur.489..318M |doi=10.1038/nature11432 |pmc=3832985 |pmid=22932268}}</ref><ref name="Vaughan">{{Cite journal |vauthors=Vaughan KL, Kaiser T, Peaden R, Anson RM, de Cabo R, Mattison JA |date=December 2017 |title=Caloric Restriction Study Design Limitations in Rodent and Nonhuman Primate Studies |journal=The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences |volume=73 |issue=1 |pages=48–53 |doi=10.1093/gerona/glx088 |pmc=5861872 |pmid=28977341}}</ref>

===Activity levels===
Calorie restriction preserves muscle tissue in nonhuman primates<ref name="McKiernan2012">{{Cite journal |display-authors=6 |vauthors=McKiernan SH, Colman RJ, Aiken E, Evans TD, Beasley TM, Aiken JM, Weindruch R, Anderson RM |date=March 2012 |title=Cellular adaptation contributes to calorie restriction-induced preservation of skeletal muscle in aged rhesus monkeys |journal=Experimental Gerontology |volume=47 |issue=3 |pages=229–236 |doi=10.1016/j.exger.2011.12.009 |pmc=3321729 |pmid=22226624}}</ref><ref name="ColmanSarco2008">{{Cite journal |vauthors=Colman RJ, Beasley TM, Allison DB, Weindruch R |date=June 2008 |title=Attenuation of sarcopenia by dietary restriction in rhesus monkeys |journal=The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences |volume=63 |issue=6 |pages=556–559 |doi=10.1093/gerona/63.6.556 |pmc=2812805 |pmid=18559628}}</ref> and rodents.<ref name="DirksNaylor">{{Cite journal |vauthors=Dirks Naylor AJ, Leeuwenburgh C |date=January 2008 |title=Sarcopenia: the role of apoptosis and modulation by caloric restriction |journal=Exercise and Sport Sciences Reviews |volume=36 |issue=1 |pages=19–24 |doi=10.1097/jes.0b013e31815ddd9d |pmid=18156949}}</ref> Muscle tissue grows when stimulated, so it has been suggested that the calorie-restricted test animals exercised more than their companions on higher calories, perhaps because animals enter a foraging state during calorie restriction. However, studies show that overall activity levels are no higher in calorie restriction than [[ad libitum]] animals in youth.<ref name="Faulks2006">{{Cite journal |vauthors=Faulks SC, Turner N, Else PL, Hulbert AJ |date=August 2006 |title=Calorie restriction in mice: effects on body composition, daily activity, metabolic rate, mitochondrial reactive oxygen species production, and membrane fatty acid composition |journal=The Journals of Gerontology. Series A, Biological Sciences and Medical Sciences |volume=61 |issue=8 |pages=781–794 |doi=10.1093/gerona/61.8.781 |pmid=16912094 |doi-access=free}}</ref>

=== Sirtuin-mediated mechanism ===

{{Main|Caloric restriction mimetic}}

Preliminary research indicates that [[sirtuin]]s are activated by fasting and serve as "energy sensors" during [[metabolism]].<ref>{{Cite journal |vauthors=Chang HC, Guarente L |date=March 2014 |title=SIRT1 and other sirtuins in metabolism |journal=Trends in Endocrinology and Metabolism |volume=25 |issue=3 |pages=138–145 |doi=10.1016/j.tem.2013.12.001 |pmc=3943707 |pmid=24388149 |hdl=1721.1/104067}}</ref> Sirtuins, specifically Sir2 (found in yeast) have been implicated in the aging of yeast,<ref name="cshs">{{Cite journal |vauthors=Guarente L |date=2007 |title=Sirtuins in aging and disease |journal=Cold Spring Harbor Symposia on Quantitative Biology |volume=72 |pages=483–488 |doi=10.1101/sqb.2007.72.024 |pmid=18419308 |doi-access=free}}</ref> and are a class of [[Conserved sequence|highly conserved]], NAD<sup>+</sup>-dependent [[histone deacetylase]] [[enzyme]]s.<ref name="Lin 12–16">{{Cite journal |vauthors=Lin SJ, Ford E, [[Marcia Haigis|Haigis M]], Liszt G, Guarente L |date=January 2004 |title=Calorie restriction extends yeast life span by lowering the level of NADH |journal=Genes & Development |volume=18 |issue=1 |pages=12–16 |doi=10.1101/gad.1164804 |pmc=314267 |pmid=14724176}}</ref> Sir2 homologs have been identified in a wide range of organisms from bacteria to humans.<ref name=cshs/><ref name="Kaeberlein, M. 1999">{{Cite journal |vauthors=Kaeberlein M, McVey M, Guarente L |date=October 1999 |title=The SIR2/3/4 complex and SIR2 alone promote longevity in Saccharomyces cerevisiae by two different mechanisms |journal=Genes & Development |volume=13 |issue=19 |pages=2570–2580 |doi=10.1101/gad.13.19.2570 |pmc=317077 |pmid=10521401}}</ref>

== See also ==
* [[Calorie deficit]]
* [[CR Society International]]
* [[Fasting]]
* [[Intermittent fasting]]
* [[List of diets]]
* [[Okinawa diet]]
* [[Very low calorie diet]]

== References ==
{{reflist}}

== Further reading ==
{{refbegin}}
* {{Cite book |title=Calorie Restriction, Aging and Longevity |vauthors=Everitt AV, Heilbronn LK, Le Couteur DG |publisher=Springer |year=2010 |isbn=978-90-481-8555-9 |veditors=Everitt AV, Rattan SI, Le Couteur DG, de Cabo R |location=New York |chapter=Food Intake, Life Style, Aging and Human Longevity}}
* {{Cite book |author-link=Ancel Keys |title=The Biology of Human Starvation |vauthors=Keys A, Brozek J, Henschel A, Mickelsen O, Taylor HL |publisher=University of Minnesota Press |year=1950 |isbn=978-0-8166-7234-9 |volume=I}}
{{refend}}

{{Diets}}
{{Longevity}}

{{DEFAULTSORT:Calorie Restriction}}
[[Category:Diets]]
[[Category:Eating behaviors]]
[[Category:Life extension]]
[[Category:Senescence]]