PMID- 6865776
OWN - NLM
STAT- MEDLINE
DCOM- 19830826
LR  - 20190725
IS  - 0026-0495 (Print)
IS  - 0026-0495 (Linking)
VI  - 32
IP  - 8
DP  - 1983 Aug
TI  - The human metabolic response to chronic ketosis without caloric restriction: 
      preservation of submaximal exercise capability with reduced carbohydrate 
      oxidation.
PG  - 769-76
AB  - To study the effect of chronic ketosis on exercise performance in 
      endurance-trained humans, five well-trained cyclists were fed a eucaloric 
      balanced diet (EBD) for one week providing 35-50 kcal/kg/d, 1.75 g protein/kg/d 
      and the remainder of kilocalories as two-thirds carbohydrate (CHO) and one-third 
      fat. This was followed by four weeks of a eucaloric ketogenic diet (EKD), 
      isocaloric and isonitrogenous with the EBD but providing less than 20 g CHO 
      daily. Both diets were appropriately supplemented to meet the recommended daily 
      allowances for vitamins and minerals. Pedal ergometer testing of maximal oxygen 
      uptake (VO2max) was unchanged between the control week (EBD-1) and week 3 of the 
      ketogenic diet (EKD-3). The mean ergometer endurance time for continuous exercise 
      to exhaustion (ENDUR) at 62%-64% of VO2max was 147 minutes at EBD-1 and 151 
      minutes at EKD-4. The ENDUR steady-state RQ dropped from 0.83 to 0.72 (P less 
      than 0.01) from EBD-1 to EKD-4. In agreement with this were a three-fold drop in 
      glucose oxidation (from 15.1 to 5.1 mg/kg/min, P less than 0.05) and a four-fold 
      reduction in muscle glycogen use (0.61 to 0.13 mmol/kg/min, P less than 0.01). 
      Neither clinical nor biochemical evidence of hypoglycemia was observed during 
      ENDUR at EKD-4. These results indicate that aerobic endurance exercise by 
      well-trained cyclists was not compromised by four weeks of ketosis. This was 
      accomplished by a dramatic physiologic adaptation that conserved limited 
      carbohydrate stores (both glucose and muscle glycogen) and made fat the 
      predominant muscle substrate at this submaximal power level.
FAU - Phinney, S D
AU  - Phinney SD
FAU - Bistrian, B R
AU  - Bistrian BR
FAU - Evans, W J
AU  - Evans WJ
FAU - Gervino, E
AU  - Gervino E
FAU - Blackburn, G L
AU  - Blackburn GL
LA  - eng
GR  - AM-26349/AM/NIADDK NIH HHS/United States
GR  - GM-22691/GM/NIGMS NIH HHS/United States
GR  - RR-88/RR/NCRR NIH HHS/United States
GR  - etc.
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Metabolism
JT  - Metabolism: clinical and experimental
JID - 0375267
RN  - 0 (Blood Glucose)
RN  - 9005-79-2 (Glycogen)
SB  - IM
MH  - Acidosis/*metabolism
MH  - Adult
MH  - Blood Glucose/analysis
MH  - *Carbohydrate Metabolism
MH  - *Diet
MH  - *Energy Intake
MH  - Glycogen/metabolism
MH  - Humans
MH  - Ketosis/*metabolism
MH  - Male
MH  - Muscles/metabolism
MH  - *Oxygen Consumption
MH  - Physical Endurance
MH  - *Physical Exertion
EDAT- 1983/08/01 00:00
MHDA- 1983/08/01 00:01
CRDT- 1983/08/01 00:00
PHST- 1983/08/01 00:00 [pubmed]
PHST- 1983/08/01 00:01 [medline]
PHST- 1983/08/01 00:00 [entrez]
AID - 0026-0495(83)90106-3 [pii]
AID - 10.1016/0026-0495(83)90106-3 [doi]
PST - ppublish
SO  - Metabolism. 1983 Aug;32(8):769-76. doi: 10.1016/0026-0495(83)90106-3.