title: Roles of caloric restriction, ketogenic diet and intermittent fasting during initiation, progression and metastasis of cancer in animal models: a systematic review and meta-analysis.
abstract: BACKGROUND
  The role of dietary restriction regimens such as caloric restriction, ketogenic diet and intermittent fasting in development of cancers has been detected via abundant preclinical experiments. However, the conclusions are controversial. We aim to review the relevant animal studies systematically and provide assistance for further clinical studies.
  
  
  METHODS
  Literatures on associations between dietary restriction and cancer published in PubMed in recent twenty years were comprehensively searched. Animal model, tumor type, feeding regimen, study length, sample size, major outcome, conclusion, quality assessment score and the interferential step of cancer were extracted from each eligible study. We analyzed the tumor incidence rates from 21 studies about caloric restriction.
  
  
  RESULTS
  Fifty-nine studies were involved in our system review. The involved studies explored roles of dietary restriction during initiation, progression and metastasis of cancer. About 90.9% of the relevant studies showed that caloric restriction plays an anti-cancer role, with the pooled OR (95%CI) of 0.20 (0.12, 0.34) relative to controls. Ketogenic diet was also positively associated with cancer, which was indicated by eight of the nine studies. However, 37.5% of the related studies obtained a negative conclusion that intermittent fasting was not significantly preventive against cancer.
  
  
  CONCLUSIONS
  Caloric restriction and ketogenic diet are effective against cancer in animal experiments while the role of intermittent fasting is doubtful and still needs exploration. More clinical experiments are needed and more suitable patterns for humans should be investigated.
authors.affiliation: Department of General Surgery, Nanjing Medical University Affiliated Cancer Hospital, Cancer Institute of Jiangsu Province, Nanjing, China; The First Clinical School of Nanjing Medical University, Nanjing, China.
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Lv
authors.affiliation: Gulou Clinical Medical College, Nanjing Medical University, Nanjing, China; Department of Gastrointestinal Surgery, Nanjing Gulou Hospital Affiliated to Medical College of Nanjing University, Nanjing, China.
authors.forename: Xingya
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Gastrointestinal Surgery, Nanjing Gulou Hospital Affiliated to Medical College of Nanjing University, Nanjing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Gastrointestinal Surgery, Nanjing Gulou Hospital Affiliated to Medical College of Nanjing University, Nanjing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Gastrointestinal Surgery, Nanjing Gulou Hospital Affiliated to Medical College of Nanjing University, Nanjing, China.
authors.forename: Wenxian
authors.initials: W
authors.lastname: Guan
mesh_terms: D000818:Animals; D031204:Caloric Restriction; D055423:Diet, Ketogenic; D004195:Disease Models, Animal; D005215:Fasting; D006801:Humans; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000178:diet therapy* / Q000453:epidemiology / Q000473:pathology; D039781:PubMed