Effects of a Low Carbohydrate, High Fat Diet Prior to ‘Carbohydrate Loading’ on Endurancecyclingperformance

Zyl, Chanel van; Murphy, Karen; Lambert, E. V.; Noakes, T. D.; Dennis, S C

doi:10.1042/cs087s032a

Cited by 3 publications

(6 citation statements)

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“…Jeukendrup et al (1995) showed that the m axim um rate of uptake and oxidation of ingested medium-chain triacylglycerols during exercise was ~0.12 g m in -1 , when the rate of ingestion was ~0.15 g m in -1 . This is in contrast to the estimated rate of oxidation of m edium -chain triacylglycerols in our study of ~0.2 g m in -1 , w hen subjects ingested medium-chain triacylglycerols at a rate of 0.43 g m in -1 (van Zyl et al, 1996). T hese studies show that m edium -chain triacylglycerols provide a lim ited, rapidly oxidized fuel for exercise.…”

Section: Ietary Fat Ingestion: Availability Of Longchain and Mediumcontrasting

confidence: 96%

“…In our recent investigations into the effects of the ingestion of m edium-chain triacylglycerols on endurance perform ance during m oderate-to high-in tensity exercise, six m ale endurance cyclists rode for 2 h at 60% Ç VO 2 peak and then im m ediately perform ed a simulated 40 km time-trial on three occasions (van Zyl et al, 1996). D uring the rides, the subjects ingested a random order of either 1 g m in -1 of U -1 4 C glucose (10 g 100 ml -1 carbohydrate), or carbohydrate (CH O ) plus an isocaloric quantity of 0.43 g m in -1 of m edium -chain triacylglycerols (10 g 100 m l -1 C HO + 4.3 g 100 m l -1 M CT ), or just m edium -chain triacylglycerols labelled with trace am ounts of U-1 4 C glucose (4.3 g 100 m l -1 M CT ).…”

Section: Ietary Fat Ingestion: Availability Of Longchain and Mediummentioning

confidence: 99%

“…In a m ore recent study, we fed ® ve endurance-trained cyclists a random order of either a high-fa t diet for 10 days or habitual diet for 10 days, followed by 3 days of carbohydrate loading (van Zyl et al, 1994). T he cyclists then perform ed a 150 min ride at 70% Ç VO 2 peak followed by a sim ulated 20 km time-trial.…”

Section: Adaptations To a Low-carbo Hydrate High -Fat Dietmentioning

confidence: 99%

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Nutritional strategies for promoting fat utilization and delaying the onset of fatigue during prolonged exercise

Lambert¹,

Hawley²,

Goedecke³

et al. 1997

Journal of Sports Sciences

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Carbohydrate ingestion before and during endurance exercise delays the onset of fatigue (reduced power output). Therefore, endurance athletes are recommended to ingest diets high in carbohydrate (70% of total energy) during competition and training. However, increasing the availability of plasma free fatty acids has been shown to slow the rate of muscle and liver glycogen depletion by promoting the utilization of fat. Ingested fat, in the form of long-chain (C16-22) triacylglycerols, is largely unavailable during acute exercise, but medium-chain (C8-10) triacylglycerols are rapidly absorbed and oxidized. We have shown that the ingestion of medium-chain triacylglycerols in combination with carbohydrate spares muscle carbohydrate stores during 2 h of submaximal (< 70% VO2 peak) cycling exercise, and improves 40 km time-trial performance. These data suggest that by combining carbohydrate and medium-chain triacylglycerols as a pre-exercise supplement and as a nutritional supplement during exercise, fat oxidation will be enhanced, and endogenous carbohydrate will be spared. We have also examined the chronic metabolic adaptations and effects on substrate utilization and endurance performance when athletes ingest a diet that is high in fat (> 70% by energy). Dietary fat adaptation for a period of at least 2-4 weeks has resulted in a nearly two-fold increase in resistance to fatigue during prolonged, low- to moderate-intensity cycling (< 70% VO2 peak). Moreover, preliminary studies suggest that mean cycling 20 km time-trial performance following prolonged submaximal exercise is enhanced by 80 s after dietary fat adaptation and 3 days of carbohydrate loading. Thus the relative contribution of fuel substrate to prolonged endurance activity may be modified by training, pre-exercise feeding, habitual diet, or by artificially altering the hormonal milieu or the availability of circulating fuels. The time course and dose-response of these effects on maximizing the oxidative contribution of fat for exercise metabolism and in exercise performance have not been systematically studied during moderate- to high-intensity exercise in humans.

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Section: Ietary Fat Ingestion: Availability Of Longchain and Mediumcontrasting

confidence: 96%

Section: Ietary Fat Ingestion: Availability Of Longchain and Mediummentioning

confidence: 99%

Section: Adaptations To a Low-carbo Hydrate High -Fat Dietmentioning

confidence: 99%

See 1 more Smart Citation

Nutritional strategies for promoting fat utilization and delaying the onset of fatigue during prolonged exercise

Lambert¹,

Hawley²,

Goedecke³

et al. 1997

Journal of Sports Sciences

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show abstract

“…[155] Thus, athletes would train for the majority of the year on a high CHO diet, adapting to a high fat diet for 7 to 10 days in the 2 weeks before a major event, then CHO loading in the final 2 to 3 days before competition. In order to test this hypothesis, van Zyl et al [149] recently had 5 well trained cyclists ingest a random order of either a high fat (65% MJ) or their habitual diet (fat 29%, CHO 53% MJ) for 10 days, followed by 3 days of a high CHO diet (65% MJ). Participants then undertook a 150-minute ride at 70% of V .…”

Section: Long Term Adaptation To High Fat Dietsmentioning

confidence: 99%

“…[156,157] Yet, to the best of our knowledge, only one study has examined the effect of a high fat diet on blood lipid profiles in athletes. [149] In that investigation, well trained individuals were fed either a high CHO (65% MJ) or high fat (65% MJ) diet for 10 days. Plasma cholesterol, high density lipoprotein cholesterol and serum TG levels were not significantly different after the 2 dietary interventions.…”

Section: Effects Of High Fat Diets On Blood Lipid Profiles and Insulimentioning

confidence: 99%

Strategies to Enhance Fat Utilisation During Exercise

Hawley

Brouns²,

Jeukendrup³

1998

Sports Medicine

101

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Time Course of the Effects of a High-Fat Diet and Voluntary Exercise on Muscle Enzyme Activity in Long-Evans Rats

Cheng

Karamizrak

Noakes

et al. 1997

Physiology & Behavior

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Effects of a Low Carbohydrate, High Fat Diet Prior to ‘Carbohydrate Loading’ on Endurancecyclingperformance

Cited by 3 publications

References 0 publications

Nutritional strategies for promoting fat utilization and delaying the onset of fatigue during prolonged exercise

Nutritional strategies for promoting fat utilization and delaying the onset of fatigue during prolonged exercise

Strategies to Enhance Fat Utilisation During Exercise

Time Course of the Effects of a High-Fat Diet and Voluntary Exercise on Muscle Enzyme Activity in Long-Evans Rats

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