title: Effects of brief perturbations in energy balance on indices of glucose homeostasis in healthy lean men.
abstract: BACKGROUND
  Little is known about the effects of short-term caloric restriction (CR) and overfeeding (OF) on glucose homeostasis in healthy lean individuals. In addition, it remains unclear whether the effects of CR and OF are reversed by a complementary feeding period.
  
  
  METHODS
  Ten healthy men participated in two cycles of controlled 7-day periods of CR and refeeding (RF; protocol A), and OF and CR (protocol B) at ±60% energy requirement. At baseline, insulin sensitivity (IS) was assessed by euglycemic clamp (M). Before and during each feeding cycle, fasting and oral glucose tolerance test-derived indices were used to estimate glucose tolerance, IS and glucose-stimulated insulin secretion.
  
  
  RESULTS
  Clamp tests revealed normal IS at baseline (M-values 9.4±2.1 mg kg⁻¹  min⁻¹, coefficient of variation (CV)(inter) 22%). M-values were significantly correlated with indices of IS. In protocol A, CR-induced weight loss (-3.0±0.4 kg) was associated with an increase in fasting IS. Postprandial IS and glucose-stimulated insulin secretion remained unchanged, but glucose tolerance decreased. RF decreased fasting and postprandial IS at increased glucose-stimulated insulin secretion. In protocol B, OF significantly increased the body weight (+1.6±0.9 kg). Concomitantly, fasting and postprandial IS decreased at increased glucose-stimulated insulin secretion. Subsequent CR reversed these effects. Inter-individual variability in indices of glucose metabolism was high with coefficients of variation ranging from 9 to 59%.
  
  
  CONCLUSIONS
  Significant changes in glucose metabolism are evident within 7-day periods of controlled OF and underfeeding. Although IS was impaired at the end of the CR-RF cycle, IS was normalized after the OF-CR cycle. At different feeding regimens, homeostatic responses of glucose metabolism were highly variable.
authors: Institute of Human Nutrition and Food Science, Christian-Albrechts University, Kiel, Germany.
authors: M
authors: M
authors: Lagerpusch
authors: A
authors: A
authors: Bosy-Westphal
authors: B
authors: B
authors: Kehden
authors: A
authors: A
authors: Peters
authors: M J
authors: MJ
authors: Müller
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D031204:Caloric Restriction; D002149:Energy Intake; D004734:Energy Metabolism / Q000502:physiology*; D015309:Glucose Clamp Technique; D005951:Glucose Tolerance Test; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000097:blood* / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology*; D000078790:Insulin Secretion; D008297:Male; D019518:Postprandial Period; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D007328:Insulin