title: Comparison of a carbohydrate-free diet vs. fasting on plasma glucose, insulin and glucagon in type 2 diabetes.
abstract: OBJECTIVE
  Hyperglycemia improves when patients with type 2 diabetes are placed on a weight-loss diet. Improvement typically occurs soon after diet implementation. This rapid response could result from low fuel supply (calories), lower carbohydrate content of the weight-loss diet, and/or weight loss per se. To differentiate these effects, glucose, insulin, C-peptide and glucagon were determined during the last 24 h of a 3-day period without food (severe calorie restriction) and a calorie-sufficient, carbohydrate-free diet.
  
  
  METHODS
  Seven subjects with untreated type 2 diabetes were studied. A randomized-crossover design with a 4-week washout period between arms was used.
  
  
  METHODS
  Results from both the calorie-sufficient, carbohydrate-free diet and the 3-day fast were compared with the initial standard diet consisting of 55% carbohydrate, 15% protein and 30% fat.
  
  
  RESULTS
  The overnight fasting glucose concentration decreased from 196 (standard diet) to 160 (carbohydrate-free diet) to 127 mg/dl (fasting). The 24 h glucose and insulin area responses decreased by 35% and 48% on day 3 of the carbohydrate-free diet, and by 49% and 69% after fasting. Overnight basal insulin and glucagon remained unchanged.
  
  
  CONCLUSIONS
  Short-term fasting dramatically lowered overnight fasting and 24 h integrated glucose concentrations. Carbohydrate restriction per se could account for 71% of the reduction. Insulin could not entirely explain the glucose responses. In the absence of carbohydrate, the net insulin response was 28% of the standard diet. Glucagon did not contribute to the metabolic adaptations observed.
authors.affiliation: Section of Endocrinology, Metabolism & Nutrition, and the Metabolic Research Laboratory, Minneapolis VA Health Care System, Minneapolis/St Paul, MN, USA; Department of Medicine, University of Minnesota, Minneapolis/St Paul, MN, USA. Electronic address: nutta001@umn.edu.
authors.forename: Frank Q
authors.initials: FQ
authors.lastname: Nuttall
authors.affiliation: Section of Endocrinology, Metabolism & Nutrition, and the Metabolic Research Laboratory, Minneapolis VA Health Care System, Minneapolis/St Paul, MN, USA; Department of Medicine, University of Minnesota, Minneapolis/St Paul, MN, USA.
authors.forename: Rami M
authors.initials: RM
authors.lastname: Almokayyad
authors.affiliation: Section of Endocrinology, Metabolism & Nutrition, and the Metabolic Research Laboratory, Minneapolis VA Health Care System, Minneapolis/St Paul, MN, USA; Department of Medicine, University of Minnesota, Minneapolis/St Paul, MN, USA; Department of Food Science & Nutrition, University of Minnesota, Minneapolis/St Paul, MN, USA.
authors.forename: Mary C
authors.initials: MC
authors.lastname: Gannon
mesh_terms: D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D002096:C-Peptide / Q000097:blood; D031204:Caloric Restriction; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000178:diet therapy*; D050528:Diet, Carbohydrate-Restricted; D004038:Diet, Reducing; D005215:Fasting; D005934:Glucagon / Q000097:blood*; D006787:Hospitals, Veterans; D006801:Humans; D006943:Hyperglycemia / Q000517:prevention & control*; D007328:Insulin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015431:Weight Loss
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D005934:Glucagon
keywords: Carbohydrate; Circadian rhythm; Diabetes; Diet; Fasting