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document
The effect of body weight changes and endurance training on 24h substrate oxidation . OBJECTIVE To investigate the effect of exercise training and dietary macronutrient composition on 24 h substrate oxidation in male , obese subjects . DESIGN A 16 month exercise intervention study was executed , including a weight loss period with a very low energy diet ( VLED ) for 2 months at the start of the study . SUBJECTS Twelve male , obese subjects ( age 36.3+/-5.1 y ; body weight 94.6+/-13.9 kg ; body mass index , BMI 30.8+/-3.0 kg/m2 ) and in an additional study 15 lean , well-trained subjects ( age 36.2+/-7.2 y ; body weight 72.2+/-5.9 kg ; BMI 22.3+/-1.7 kg/m2 ) participated . MEASUREMENTS Substrate oxidation was measured during a standardized 36 h stay in the respiration chamber at the start of the study ( 0 months ) , and at 4 , 10 and 16 months . In the respiration chamber subjects were randomly assigned to a high-fat ( Hi.F ) diet ( 60 % of energy ( En % ) fat ) or a reduced-fat ( Red.F ) diet ( 30 En % fat ) . The well-trained group was measured once in the respiration chamber for 36 h according to the same protocol . RESULTS At any time point , independent of the diet consumed , the 24 h carbohydrate ( CHO ) balances in the chamber were mostly negative ( means ranging from +31 to -98 g/d ) and the fat balances mostly positive ( means ranging from -26 to +38 g/d ) for the obese a well as for the lean , well-trained group . For both diets an increased shortage of 70 g of CHO was found at 16 months compared with 4 months , and an increase in fat balance of 33 g during the same time period in the obese subjects , indicating that CHO oxidation had increased with 12 months endurance training . In the well-trained group the 24h CHO balance was even more negative for both types of diet ( -103 to -185 g/d for the Red.F and Hi.F diet , respectively ) under similar conditions compared with the trained obese group . CONCLUSION The changes in 24 h substrate utilization in the obese , as well as in the well-trained group , suggest that endurance training increased the reliance on carbohydrate oxidation and therefore did not increase 24 fat oxidation .
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Intervention_Other
exercise training and
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Intervention_Educational
dietary macronutrient composition
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Intervention_Other
exercise intervention
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Intervention_Other
very low energy diet ( VLED
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Intervention_Pharmacological
)
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Intervention_Other
high-fat ( Hi.F ) diet
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Intervention_Pharmacological
( 60 % of energy ( En % ) fat ) or a
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Intervention_Other
reduced-fat ( Red.F ) diet
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Intervention_Pharmacological
( 30 En % fat
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Outcome_Physical
24h substrate oxidation
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Outcome_Physical
24 h substrate oxidation
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Outcome_Physical
Substrate oxidation
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Outcome_Physical
24 h carbohydrate ( CHO ) balances
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Outcome_Physical
fat balances
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Outcome_Physical
shortage of 70 g of CHO
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Outcome_Physical
fat balance
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Outcome_Physical
CHO oxidation
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Outcome_Physical
24h CHO balance
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Outcome_Physical
24 h substrate utilization
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Outcome_Physical
carbohydrate oxidation
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Outcome_Physical
24 fat oxidation
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Participant_Sex
male
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Participant_Condition
obese
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Participant_Sample-size
Twelve
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Participant_Sex
male
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Participant_Condition
obese
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Participant_Age
36.3+/-5.1
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Participant_Sample-size
15
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Participant_Age
36.2+/-7.2