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Caloric Restriction: Difference between revisions
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=== Longevity === | === Longevity === | ||
Currently, there is no scientific evidence that permanent calorie restriction – with adequate [[Human nutrition|nutrition]] – leads to an extension of life expectancy compared to a lean adult.{{cite web |author=Stephan Schleim |url=https://www.heise.de/tp/features/Auf-der-Suche-nach-dem-Jungbrunnen-das-Beispiel-Kalorienreduktion-3395506.html |title=In Search of the Fountain of Youth: The Example of Calorie Restriction |website=[[Telepolis|heise.de]] |date=2012-08-31 |access-date=2015-05-11}} It is undisputed that severe [[Obesity|overweight]], i.e., [[Obesity|obesity]], leads to a reduction in average and maximum life expectancy. However, [[Systematic review|reviews]] have confirmed that calorie restriction (or [[Intermittent fasting]]) in healthy adults is likely to lead to similar [[Anti-aging|life extension]] – extensions of health and lifespan – as observed in animal experiments. They describe the health effects and molecular mechanisms of such phases, including [[Autophagy]]. A problem with scientific studies on this is that the relatively long lifespan of humans makes it difficult to directly test such interventions.{{cite journal |last1=Green |first1=Cara L. |last2=Lamming |first2=Dudley W. |last3=Fontana |first3=Luigi |title=Molecular mechanisms of dietary restriction promoting health and longevity |journal=Nature Reviews Molecular Cell Biology |date=2021-09-13 |pages=1–18 |doi=10.1038/s41580-021-00411-4 |language=en |issn=1471-0080}}{{cite journal |last1=Wilson |first1=Kenneth A. |last2=Chamoli |first2=Manish |last3=Hilsabeck |first3=Tyler A. |last4=Pandey |first4=Manish |last5=Bansal |first5=Sakshi |last6=Chawla |first6=Geetanjali |last7=Kapahi |first7=Pankaj |title=Evaluating the beneficial effects of dietary restrictions: A framework for precision nutrigeroscience |journal=Cell Metabolism |date=2021-09-22 |doi=10.1016/j.cmet.2021.08.018 |language=en |issn=1550-4131 |url=https://www.researchgate.net/publication/354822240}} Periods in which calorie intake is limited to a constant deficit can be combined with intermittent fasting (periods with intervals of consuming no food, only water, and tea/coffee, for example) and variants of the [[Mediterranean diet|Mediterranean diet]], which typically have long-term cardiovascular benefits and could also increase longevity.{{cite journal |last1=O’Keefe |first1=James H. |last2=Torres-Acosta |first2=Noel |last3=O’Keefe |first3=Evan L. |last4=Saeed |first4=Ibrahim M. |last5=Lavie |first5=Carl J. |last6=Smith |first6=Sarah E. |last7=Ros |first7=Emilio |title=A Pesco-Mediterranean Diet With Intermittent Fasting |journal=Journal of the American College of Cardiology |date=2020-09 |volume=76 |issue=12 |pages=1484–1493 |doi=10.1016/j.jacc.2020.07.049|pmid=32943166 }} Which protocols (such as duration and magnitude of the calorie deficit) and combinations (see, for example, [[Caloric restriction mimetic]], [[Coffee#Effects of coffee|effects of coffee]], and [[AMP-activated protein kinase|AMPK]]) with calorie restriction are effective or most effective in humans in general and depending on the individual{{cite journal |doi=10.1016/j.cmet.2021.08.018}} is still unknown. | Currently, there is no scientific evidence that permanent calorie restriction – with adequate [[Human nutrition|nutrition]] – leads to an extension of life expectancy compared to a lean adult.{{cite web |author=Stephan Schleim |url=https://www.heise.de/tp/features/Auf-der-Suche-nach-dem-Jungbrunnen-das-Beispiel-Kalorienreduktion-3395506.html |title=In Search of the Fountain of Youth: The Example of Calorie Restriction |website=[[Telepolis|heise.de]] |date=2012-08-31 |access-date=2015-05-11}} It is undisputed that severe [[Obesity|overweight]], i.e., [[Obesity|obesity]], leads to a reduction in average and maximum life expectancy. However, [[Systematic review|reviews]] have confirmed that calorie restriction (or [[Intermittent fasting]]) in healthy adults is likely to lead to similar [[Anti-aging|life extension]] – extensions of health and lifespan – as observed in animal experiments. They describe the health effects and molecular mechanisms of such phases, including [[Autophagy]]. A problem with scientific studies on this is that the relatively long lifespan of humans makes it difficult to directly test such interventions.{{cite journal |last1=Green |first1=Cara L. |last2=Lamming |first2=Dudley W. |last3=Fontana |first3=Luigi |title=Molecular mechanisms of dietary restriction promoting health and longevity |journal=Nature Reviews Molecular Cell Biology |date=2021-09-13 |pages=1–18 |doi=10.1038/s41580-021-00411-4 |language=en |issn=1471-0080}}{{cite journal |last1=Wilson |first1=Kenneth A. |last2=Chamoli |first2=Manish |last3=Hilsabeck |first3=Tyler A. |last4=Pandey |first4=Manish |last5=Bansal |first5=Sakshi |last6=Chawla |first6=Geetanjali |last7=Kapahi |first7=Pankaj |title=Evaluating the beneficial effects of dietary restrictions: A framework for precision nutrigeroscience |journal=Cell Metabolism |date=2021-09-22 |doi=10.1016/j.cmet.2021.08.018 |language=en |issn=1550-4131 |url=https://www.researchgate.net/publication/354822240}} Periods in which calorie intake is limited to a constant deficit can be combined with intermittent fasting (periods with intervals of consuming no food, only water, and tea/coffee, for example) and variants of the [[Mediterranean diet|Mediterranean diet]], which typically have long-term cardiovascular benefits and could also increase longevity.{{cite journal |last1=O’Keefe |first1=James H. |last2=Torres-Acosta |first2=Noel |last3=O’Keefe |first3=Evan L. |last4=Saeed |first4=Ibrahim M. |last5=Lavie |first5=Carl J. |last6=Smith |first6=Sarah E. |last7=Ros |first7=Emilio |title=A Pesco-Mediterranean Diet With Intermittent Fasting |journal=Journal of the American College of Cardiology |date=2020-09 |volume=76 |issue=12 |pages=1484–1493 |doi=10.1016/j.jacc.2020.07.049|pmid=32943166 }} Which protocols (such as duration and magnitude of the calorie deficit) and combinations (see, for example, [[Caloric restriction mimetic]], [[Coffee#Effects of coffee|effects of coffee]], and [[AMP-activated protein kinase|AMPK]]) with calorie restriction are effective or most effective in humans in general and depending on the individual{{cite journal |doi=10.1016/j.cmet.2021.08.018}} is still unknown. | ||
===Risks of Calorie Restriction in Humans=== | |||
Specifically in the USA, the results of animal experiments have led to many practitioners adopting calorie restriction, particularly in [[California]].<ref name="abs2009" /> A group of these practitioners formed the ''Calorie Restriction Society''. Excessive calorie reduction always carries the risk of malnutrition, which can negatively affect physical and mental health. There are repeated warnings about potential [[Eating disorder|eating disorders]] with calorie restriction. On the other hand, a study showed that calorie restriction does not lead to an increase in [[Anorexia nervosa|anorexia]] or [[Bulimia nervosa|bulimia]]. The psychological effects of calorie restriction were evaluated as positive in this study.{{cite journal|pmid=18248104|title=Is Caloric Restriction Associated With Development of Eating-Disorder Symptoms? Results From the CALERIE Trial|journal=[[Health Psychology]]|volume=27|year=2008|pages=S32–S42|first=D. A. Williamson et al.}} | |||
Long-term [[Malnutrition|undernutrition]] can, besides positive effects, also lead to various [[Deficiency disease|deficiency diseases]]. Developmental disorders can occur in minors. Cold sensitivity may increase.{{cite journal|pmc=2786899|title=Cellular mechanisms of cardioprotection by calorie restriction: state of the science and future perspectives|publisher=Ncbi.nlm.nih.gov|date=2012-10-19|pmid=19944269|doi=10.1016/j.cger.2009.07.002|volume=25|issue=4|journal=Clin. Geriatr. Med.|pages=715–32, ix|first=E. Marzetti et al.}} | |||
Ovulation can be suspended in women with very low BMI, resulting in temporary infertility. | |||
{{cite journal|pmc=2786899|pmid=19944269}} | |||
In the [[Minnesota Starvation Experiment]], anemia, edema in the lower extremities, muscle wasting, weakness, neurological impairments, dizziness, irritability, lethargy, and depression were observed in adult males undergoing a six-month calorie restriction with a 90% carbohydrate diet.{{cite book|last1=Keys|first1=A.|last2=Brozek|first2=J.|last3=Henschels|first3=A.|last4=Mickelsen|first4=O.|last5=Taylor|first5=H.|title=The Biology of Human Starvation|year=1950|volume=2|publisher=University of Minnesota Press|location=Minneapolis|page=1133}} | |||
Short-term calorie restriction can lead to muscle wasting and reduced [[Bone density|bone density]].{{cite journal|last1=Morley|first1=John E|last2=Chahla|first2=Elie|last3=Alkaade|first3=Saad|title=Antiaging, longevity and calorie restriction|journal=Current Opinion in Clinical Nutrition and Metabolic Care|volume=13|issue=1|pages=40–5|year=2010|pmid=19851100|doi=10.1097/MCO.0b013e3283331384}} | |||
In individuals with low body fat, calorie restriction can be harmful.{{cite journal|last1=Fontana|first1=L.|last2=Klein|first2=S.|title=Aging, Adiposity, and Calorie Restriction|journal=JAMA|volume=297|issue=9|pages=986–94|year=2007|pmid=17341713|doi=10.1001/jama.297.9.986}} | |||
== Mechanism == | == Mechanism == | ||
The reasons for the lifespan extension in model organisms through caloric restriction are not yet fully understood. The underlying mechanism of this effect remains unknown. It's possible that the extension of lifespan results from improved health status due to the absence of obesity and the delayed onset of age-related diseases of the metabolic syndrome such as cardiovascular diseases and Type II Diabetes mellitus. | The reasons for the lifespan extension in model organisms through caloric restriction are not yet fully understood. The underlying mechanism of this effect remains unknown. It's possible that the extension of lifespan results from improved health status due to the absence of obesity and the delayed onset of age-related diseases of the metabolic syndrome such as cardiovascular diseases and Type II Diabetes mellitus. | ||