title: Calorie Restriction and Matched Weight Loss From Exercise: Independent and Additive Effects on Glucoregulation and the Incretin System in Overweight Women and Men.
abstract: OBJECTIVE
  It is not known whether calorie restriction (CR) has additive benefits to those from exercise (EX)-induced weight loss. We hypothesized that weight loss from CR and EX (CREX) improves insulin sensitivity more than matched weight loss induced by EX or CR alone and that the incretin system may be involved in adaptations to CR.
  
  
  METHODS
  Sedentary, overweight men and women (n = 52, 45-65 years of age) were randomized to undergo 6-8% weight loss by using CR, EX, or CREX. Glucose, insulin, C-peptide, insulin sensitivity, and incretin hormones (glucagon-like peptide 1 [GLP-1] and glucose-dependent insulinotropic polypeptide [GIP]) were measured during frequently sampled oral glucose tolerance tests (FSOGTTs). Incretin effects on insulin secretion were measured by comparing insulin secretion rates from the FSOGTTs to those from a glycemia-matched glucose infusion.
  
  
  RESULTS
  Despite similar weight losses in all groups, insulin sensitivity index values increased twofold more in the CREX group (2.09 ± 0.35 μM/kg/pM × 100) than in the CR (0.89 ± 0.39 μM/kg/pM × 100) and EX (1.04 ± 0.39 μM/kg/pM × 100) groups. Postprandial GLP-1 concentrations decreased only in the CR group (P = 0.04); GIP concentrations decreased in all groups. Incretin effects on insulin secretion were unchanged.
  
  
  CONCLUSIONS
  CR and EX have additive beneficial effects on glucoregulation. Furthermore, the adaptations to CR may involve reductions in postprandial GLP-1 concentrations. These findings underscore the importance of promoting both CR and EX for optimal health. However, because data from participants who withdrew from the study and from those who did not adhere to the intervention were excluded, the results may be limited to individuals who are capable of adhering to a healthy lifestyle intervention.
authors: Department of Nutrition and Dietetics, Saint Louis University, St. Louis, MO Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO eweiss4@slu.edu.
authors: Edward P
authors: EP
authors: Weiss
authors: Division of Endocrinology, School of Medicine, Saint Louis University, St. Louis, MO.
authors: Stewart G
authors: SG
authors: Albert
authors: Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO.
authors: Dominic N
authors: DN
authors: Reeds
authors: Department of Nutrition and Dietetics, Saint Louis University, St. Louis, MO.
authors: Kathleen S
authors: KS
authors: Kress
authors: Department of Biomedical Laboratory Science, Saint Louis University, St. Louis, MO.
authors: Uthayashanker R
authors: UR
authors: Ezekiel
authors: Department of Nutrition and Dietetics, Saint Louis University, St. Louis, MO.
authors: Jennifer L
authors: JL
authors: McDaniel
authors: Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO.
authors: Bruce W
authors: BW
authors: Patterson
authors: Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO.
authors: Samuel
authors: S
authors: Klein
authors: Division of Geriatrics and Nutritional Science, Washington University School of Medicine, St. Louis, MO Division of Endocrinology, Diabetes, and Metabolism, Baylor College of Medicine, Houston, TX.
authors: Dennis T
authors: DT
authors: Villareal
mesh_terms: D000222:Adaptation, Physiological; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000378:metabolism; D031204:Caloric Restriction / Q000379:methods*; D002149:Energy Intake / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D005749:Gastric Inhibitory Polypeptide / Q000378:metabolism; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism; D005947:Glucose / Q000008:administration & dosage; D005951:Glucose Tolerance Test; D006801:Humans; D054795:Incretins / Q000502:physiology; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology; D000078790:Insulin Secretion; D008019:Life Style; D008297:Male; D008875:Middle Aged; D050177:Overweight / Q000628:therapy*; D019518:Postprandial Period / Q000502:physiology; D015431:Weight Loss / Q000502:physiology
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D054795:Incretins; D007328:Insulin; D005749:Gastric Inhibitory Polypeptide; D052216:Glucagon-Like Peptide 1; D005947:Glucose