title: Effect of short-term starvation versus high-fat diet on intramyocellular triglyceride accumulation and insulin resistance in physically fit men.
abstract: It is currently believed that intramyocellular triglyceride (IMTG) accumulation and insulin resistance are a consequence of dietary fat ingestion and/or the elevated circulating lipid levels associated with chronic fat surplus. The purpose of this study was to compare the effect of short-term starvation versus low-carbohydrate (CHO)/high-fat diet on IMTG accumulation and the development of insulin resistance in physically fit men. Intramyocellular triglyceride content, measured as intramyocellular lipid (IMCL) by proton magnetic resonance spectroscopy (1H-MRS), and glucose tolerance/insulin sensitivity, assessed by frequently sampled intravenous glucose tolerance test (IVGTT), were determined after 67 h of: (a) water-only starvation (S); and (b) very low-CHO/high-fat diet (LC). These diets had in common significant restriction of CHO availability but large differences in fat content. All results were compared with those measured after a mixed CHO diet (C). Dietary interventions were administered by cross-over design. The level of dietary-induced IMTG accumulation (P = 0.46), insulin resistance (P = 0.27) and glucose intolerance (P = 0.29) was not different between S and LC treatments. Intramyocellular triglyceride content and insulin sensitivity were negatively correlated (r = -0.63, P < 0.01). Therefore, whilst insulin resistance may be due to fat accumulation at a cellular level, in the integrated human organism this outcome is not exclusively a function of dietary fat intake. The comparable level of IMTG accumulation and insulin resistance following S and LC may suggest that these metabolic perturbations are largely a consequence of the increased lipolytic response associated with CHO restriction.
authors.affiliation: The School of Exercise and Sport Science, The University of Sydney, Lidcombe 1825, Australia. n.johnson@fhs.usyd.edu.au
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Johnson
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Stannard
authors.forename: David S
authors.initials: DS
authors.lastname: Rowlands
authors.forename: Phillip G
authors.initials: PG
authors.lastname: Chapman
authors.forename: Campbell H
authors.initials: CH
authors.lastname: Thompson
authors.forename: Helen
authors.initials: H
authors.lastname: O'Connor
authors.forename: Toos
authors.initials: T
authors.lastname: Sachinwalla
authors.forename: Martin W
authors.initials: MW
authors.lastname: Thompson
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D004041:Dietary Fats / Q000378:metabolism*; D005215:Fasting / Q000502:physiology*; D005508:Food Deprivation / Q000502:physiology*; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010809:Physical Fitness / Q000502:physiology*; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D004041:Dietary Fats; D014280:Triglycerides