title: The effect of alternate-day caloric restriction on the metabolic consequences of 8 days of bed rest in healthy lean men: a randomized trial.
abstract: Physical activity and alternate-day fasting/caloric restriction may both ameliorate aspects of the metabolic syndrome, such as insulin resistance, visceral fat mass accumulation, and cognitive impairment by overlapping mechanisms. The purpose of this study was to test the hypothesis that alternate-day caloric restriction (ADCR) with overall energy balance would reduce insulin resistance and accumulation of visceral fat, in addition to improving cognitive functions, after 8 consecutive days in bed. Healthy, lean men (n = 20) were randomized to 1) 8 days of bed rest with three daily isoenergetic meals (control group, n = 10); and 2) 8 days of bed rest with 25% of total energy requirements every other day and 175% of total energy requirements every other day (ADCR group). Oral glucose tolerance testing, dual-energy X-ray absorptiometry (DXA) scans, magnetic resonance imaging of the abdomen and brain, V̇o2max, and tests for cognitive function were performed before and after bed rest. In addition, daily fasting blood samples and 24-h glucose profiles by continuous glucose monitoring system were assessed during the 8 days of bed rest period. Bed rest induced insulin resistance, visceral fat accumulation, and worsening of mood. No positive effects emerged from ADCR on these negative health outcomes. Compared with the control group, ADCR was associated with improved and steadier glycemic control on fasting days and higher glycemic fluctuation and indexes of insulin resistance on overeating days. In contrast to our hypothesis, the metabolic impairment induced by 8 days of bed rest was not counteracted by ADCR with overall energy balance.
  Alternate-day caloric restriction without overall energy reduction does not ameliorate the metabolic impairment induced in lean men by 8 days of bed rest.
authors.affiliation: The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; nmharder@gmail.com.
authors.forename: Nina Majlund
authors.identifier: http://orcid.org/0000-0002-8651-5544
authors.initials: NM
authors.lastname: Harder-Lauridsen
authors.affiliation: The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Signe Tellerup
authors.initials: ST
authors.lastname: Nielsen
authors.affiliation: Center for Bioethics, Harvard Medical School, Boston, Massachusetts.
authors.forename: Sebastian Porsdam
authors.initials: SP
authors.lastname: Mann
authors.affiliation: The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Mark Preben
authors.initials: MP
authors.lastname: Lyngbæk
authors.affiliation: Applied Physiology and Nutrition Research Group, University of São Paulo, São Paulo, Brazil.
authors.forename: Fabiana Braga
authors.initials: FB
authors.lastname: Benatti
authors.affiliation: Department of Diagnostic Sciences, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Annika Reynberg
authors.initials: AR
authors.lastname: Langkilde
authors.affiliation: Department of Clinical Physiology, Nuclear Medicine, and PET, Rigshospitalet, Copenhagen, Denmark; and.
authors.forename: Ian
authors.initials: I
authors.lastname: Law
authors.affiliation: The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Wedell-Neergaard
authors.affiliation: Department of Diagnostic Sciences, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Carsten
authors.initials: C
authors.lastname: Thomsen
authors.affiliation: Department of Neuroanaesthesiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Kirsten
authors.identifier: http://orcid.org/0000-0003-3058-1072
authors.initials: K
authors.lastname: Møller
authors.affiliation: The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Karstoft
authors.affiliation: The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Bente Klarlund
authors.initials: BK
authors.lastname: Pedersen
authors.affiliation: The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Rikke
authors.initials: R
authors.lastname: Krogh-Madsen
mesh_terms: D000328:Adult; D000339:Affect / Q000502:physiology; D001510:Bed Rest / Q000009:adverse effects*; D001786:Blood Glucose / Q000378:metabolism; D031204:Caloric Restriction / Q000379:methods; D003071:Cognition / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology; D005215:Fasting / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D005951:Glucose Tolerance Test / Q000379:methods; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology; D050152:Intra-Abdominal Fat / Q000378:metabolism; D008297:Male; D024821:Metabolic Syndrome / Q000378:metabolism / Q000503:physiopathology*; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D007328:Insulin; D005947:Glucose
keywords: alternate-day fasting; clinical; cognitive performance; inactivity; metabolism; oral glucose tolerance test; visceral fat mass