PMID- 10599981
OWN - NLM
STAT- MEDLINE
DCOM- 19991229
LR  - 20190725
IS  - 0026-0495 (Print)
IS  - 0026-0495 (Linking)
VI  - 48
IP  - 12
DP  - 1999 Dec
TI  - Metabolic adaptations to a high-fat diet in endurance cyclists.
PG  - 1509-17
AB  - We examined the time course of metabolic adaptations to 15 days of a high-fat 
      diet (HFD). Sixteen endurance-trained cyclists were assigned randomly to a 
      control (CON) group, who consumed their habitual diet (30% +/- 8% mJ fat), or a 
      HFD group, who consumed a high-fat isocaloric diet (69% +/- 1% mJ fat). At 5-day 
      intervals, the subjects underwent an oral glucose tolerance test (OGTT); on the 
      next day, they performed a 2.5-hour constant-load ride at 70% peak oxygen 
      consumption (VO2peak), followed by a simulated 40-km cycling time-trial while 
      ingesting a 10% 14C-glucose + 3.44% medium-chain triglyceride (MCT) emulsion at a 
      rate of 600 mL/h. In the OGTT, plasma glucose concentrations at 30 minutes 
      increased significantly after 5 days of the HFD and remained elevated at days 10 
      and 15 versus the levels measured prior to the HFD (P < .05). The activity of 
      carnitine acyltransferase (CAT) in biopsies of the vastus lateralis muscle also 
      increased from 0.45 to 0.54 micromol/g/min over days 0 to 10 of the HFD (P < .01) 
      without any change in citrate synthase (CS) or 3-hydroxyacyl-coenzyme A 
      dehydrogenase (3-HAD) activities. Changes in glucose tolerance and CAT activity 
      were associated with a shift from carbohydrate (CHO) to fat oxidation during 
      exercise (P < .001), which occurred within 5 to 10 days of the HFD. During the 
      constant-load ride, the calculated oxidation of muscle glycogen was reduced from 
      1.5 to 1.0 g/min (P < .001) after 15 days of the HFD. Ingestion of a HFD for as 
      little as 5 to 10 days significantly altered substrate utilization during 
      submaximal exercise but did not attenuate the 40-km time-trial performance.
FAU - Goedecke, J H
AU  - Goedecke JH
AD  - Medical Research Council/University of Capetown Bioenergetics of Exercise 
      Research Unit, University of Cape Town Medical School, Newlands, South Africa.
FAU - Christie, C
AU  - Christie C
FAU - Wilson, G
AU  - Wilson G
FAU - Dennis, S C
AU  - Dennis SC
FAU - Noakes, T D
AU  - Noakes TD
FAU - Hopkins, W G
AU  - Hopkins WG
FAU - Lambert, E V
AU  - Lambert EV
LA  - eng
PT  - Clinical Trial
PT  - Journal Article
PT  - Randomized Controlled Trial
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Metabolism
JT  - Metabolism: clinical and experimental
JID - 0375267
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Dietary Fats)
SB  - IM
MH  - *Adaptation, Physiological
MH  - Adult
MH  - Bicycling/*physiology
MH  - Blood/metabolism
MH  - Dietary Carbohydrates/metabolism
MH  - Dietary Fats/*administration & dosage/metabolism/pharmacology
MH  - Glucose Tolerance Test
MH  - Humans
MH  - Male
MH  - Muscle, Skeletal/enzymology
MH  - Osmolar Concentration
MH  - Physical Endurance/*physiology
EDAT- 1999/12/22 00:00
MHDA- 1999/12/22 00:01
CRDT- 1999/12/22 00:00
PHST- 1999/12/22 00:00 [pubmed]
PHST- 1999/12/22 00:01 [medline]
PHST- 1999/12/22 00:00 [entrez]
AID - S0026-0495(99)90238-X [pii]
AID - 10.1016/s0026-0495(99)90238-x [doi]
PST - ppublish
SO  - Metabolism. 1999 Dec;48(12):1509-17. doi: 10.1016/s0026-0495(99)90238-x.