Document Detail


Capacity for moderate exercise in obese subjects after adaptation to a hypocaloric, ketogenic diet.
MedLine Citation:
PMID:  7000826     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
To study the capacity for moderate endurance exercise and change in metabolic fuel utilization during adaptation to a ketogenic diet, six moderately obese, untrained subjects were fed a eucaloric, balanced diet (base line) for 2 wk, followed by 6 wk of a protein-supplemented fast (PSF), which provided 1.2 g of protein/kg ideal body wt, supplemented with minerals and vitamins. The mean weight loss was 10.6 kg. The duration of treadmill exercise to subjective exhaustion was 80% of base line after 1 wk of the PSF, but increased to 155% after 6 wk. Despite adjusting up to base line, with a backpack, the subjects' exercise weight after 6 wk of dieting, the final exercise test was performed at a mean of 60% of maximum aerobic capacity, whereas the base-line level was 76%. Resting vastus lateralis glycogen content fell to 57% of base line after 1 wk of the PSF, but rose to 69% after 6 wk, at which time no decrement in muscle glycogen was measured after >4 h of uphill walking. The respiratory quotient (RQ) during steady-state exercise was 0.76 during base line, and fell progressively to 0.66 after 6 wk of the PSF. Blood glucose was well maintained during exercise in ketosis. The sum of acetoacetate and beta hydroxybutyrate rose from 3.28 to 5.03 mM during exercise after 6 wk of the PSF, explaining in part the low exercise RQ. The low RQ and the fact that blood glucose and muscle glycogen were maintained during exhausting exercise after 6 wk of a PSF suggest that prolonged ketosis results in an adaptation, after which lipid becomes the major metabolic fuel, and net carbohydrate utilization is markedly reduced during moderate but ultimately exhausting exercise.
Authors:
S D Phinney; E S Horton; E A Sims; J S Hanson; E Danforth; B M LaGrange
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of clinical investigation     Volume:  66     ISSN:  0021-9738     ISO Abbreviation:  J. Clin. Invest.     Publication Date:  1980 Nov 
Date Detail:
Created Date:  1981-01-29     Completed Date:  1981-01-29     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7802877     Medline TA:  J Clin Invest     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1152-61     Citation Subset:  AIM; IM; S    
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MeSH Terms
Descriptor/Qualifier:
Adult
Exercise Test
Fatty Acids, Nonesterified / blood
Female
Glucagon / blood
Glycogen / analysis
Humans
Insulin / blood
Male
Muscles / analysis
Obesity / blood,  diet therapy*,  physiopathology
Oxygen Consumption
Physical Exertion*
Pyruvates / blood
Thyroid Hormones / blood
Grant Support
ID/Acronym/Agency:
AM 10254/AM/NIADDK NIH HHS; AM 18535/AM/NIADDK NIH HHS; RR-109/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Fatty Acids, Nonesterified; 0/Pyruvates; 0/Thyroid Hormones; 11061-68-0/Insulin; 9005-79-2/Glycogen; 9007-92-5/Glucagon
Comments/Corrections

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