title: The effects of weight cycling on lifespan in male C57BL/6J mice.
abstract: OBJECTIVE
  With the increasing rates of obesity, many people diet in an attempt to lose weight. As weight loss is seldom maintained in a single effort, weight cycling is a common occurrence. Unfortunately, reports from clinical studies that have attempted to determine the effect of weight cycling on mortality are in disagreement, and to date, no controlled animal study has been performed to assess the impact of weight cycling on longevity. Therefore, our objective was to determine whether weight cycling altered lifespan in mice that experienced repeated weight gain and weight loss throughout their lives.
  
  
  METHODS
  Male C57BL/6J mice were placed on one of three lifelong diets: a low-fat (LF) diet, a high-fat (HF) diet or a cycled diet in which the mice alternated between 4 weeks on the LF diet and 4 weeks on the HF diet. Body weight, body composition, several blood parameters and lifespan were assessed.
  
  
  RESULTS
  Cycling between the HF and LF diet resulted in large fluctuations in body weight and fat mass. These gains and losses corresponded to significant increases and decreases, respectively, in leptin, resistin, GIP, IGF-1, glucose, insulin and glucose tolerance. Surprisingly, weight cycled mice had no significant difference in lifespan (801±45 days) as compared to LF-fed controls (828±74 days), despite being overweight and eating a HF diet for half of their lives. In contrast, the HF-fed group experienced a significant decrease in lifespan (544±73 days) compared with LF-fed controls and cycled mice.
  
  
  CONCLUSIONS
  This is the first controlled mouse study to demonstrate the effect of lifelong weight cycling on longevity. The act of repeatedly gaining and losing weight, in itself, did not decrease lifespan and was more beneficial than remaining obese.
authors.affiliation: Edison Biotechnology Institute, Konneker Research Laboratories, Ohio University, Athens, OH 45701, USA. list@ohio.edu
authors.forename: E O
authors.initials: EO
authors.lastname: List
authors.forename: D E
authors.initials: DE
authors.lastname: Berryman
authors.forename: J
authors.initials: J
authors.lastname: Wright-Piekarski
authors.forename: A
authors.initials: A
authors.lastname: Jara
authors.forename: K
authors.initials: K
authors.lastname: Funk
authors.forename: J J
authors.initials: JJ
authors.lastname: Kopchick
mesh_terms: D000818:Animals; D002096:C-Peptide / Q000378:metabolism; D018932:Chemokine CCL2 / Q000378:metabolism; D018752:Diet, Fat-Restricted; D059305:Diet, High-Fat; D002149:Energy Intake; D005749:Gastric Inhibitory Polypeptide / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D020738:Leptin / Q000378:metabolism*; D008136:Longevity; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000401:mortality / Q000473:pathology*; D010446:Peptide Fragments / Q000378:metabolism; D052243:Resistin / Q000378:metabolism; D013997:Time Factors; D015430:Weight Gain; D015431:Weight Loss
chemical_list: D002096:C-Peptide; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D007328:Insulin; D015850:Interleukin-6; D020738:Leptin; D010446:Peptide Fragments; D052243:Resistin; C499623:Retn protein, mouse; C577686:interleukin-6, mouse; C049962:gastric inhibitory polypeptide (1-39); D005749:Gastric Inhibitory Polypeptide