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Low Carbohydrate, High Fat diet impairs exercise economy

bertiedog

Senior Member
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1,738
Location
South East England, UK
I can across this study which I found very interesting with regard to the discussions about how we might be utilising carbohydrate for ATP. This study involves elite athletes and it seems to show that their performance was hindered by a ketogenic diet.

This got me thinking along the lines of if elite athletes have problems with using a high fat diet to improve their performance, the authors say this is because this burns up so much oxygen to make ATP, then surely it has to be similar for people with an illness like ME/CFS?

The comments regarding this study are from Examine.com so hope its ok to post?

Pam
 
Messages
2,158
I've just looked up Examine.com and their research section seems to be behind a paywall. Was the research you refer to published in a scientific journal? And if so, can you give a link so we can see it?
 

bertiedog

Senior Member
Messages
1,738
Location
South East England, UK
Here is the abstract, it does say its Open Access

Research Paper
Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers
AuthorsleyFirst published: 14 February 2017Full publication history
  • DOI: 10.1113/JP273230 View/save citation
  • Cited by (CrossRef): 3 articles
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  • Funding Information
Abstract
Key points
  • Three weeks of intensified training and mild energy deficit in elite race walkers increases peak aerobic capacity independent of dietary support.
  • Adaptation to a ketogenic low carbohydrate, high fat (LCHF) diet markedly increases rates of whole-body fat oxidation during exercise in race walkers over a range of exercise intensities.
  • The increased rates of fat oxidation result in reduced economy (increased oxygen demand for a given speed) at velocities that translate to real-life race performance in elite race walkers.
  • In contrast to training with diets providing chronic or periodised high carbohydrate availability, adaptation to an LCHF diet impairs performance in elite endurance athletes despite a significant improvement in peak aerobic capacity.
Abstract
We investigated the effects of adaptation to a ketogenic low carbohydrate (CHO), high fat diet (LCHF) during 3 weeks of intensified training on metabolism and performance of world-class endurance athletes. We controlled three isoenergetic diets in elite race walkers: high CHO availability (g kg−1 day−1: 8.6 CHO, 2.1 protein, 1.2 fat) consumed before, during and after training (HCHO, n = 9); identical macronutrient intake, periodised within or between days to alternate between low and high CHO availability (PCHO, n = 10); LCHF (< 50 g day−1 CHO; 78% energy as fat; 2.1 g kg−1 day−1 protein; LCHF, n = 10). Post-intervention,
tjp12142-math-0001.png
during race walking increased in all groups (P < 0.001, 90% CI: 2.55, 5.20%). LCHF was associated with markedly increased rates of whole-body fat oxidation, attaining peak rates of 1.57 ± 0.32 g min−1 during 2 h of walking at ∼80%
tjp12142-math-0002.png
. However, LCHF also increased the oxygen (O2) cost of race walking at velocities relevant to real-life race performance: O2 uptake (expressed as a percentage of new
tjp12142-math-0003.png
) at a speed approximating 20 km race pace was reduced in HCHO and PCHO (90% CI: −7.047, −2.55 and −5.18, −0.86, respectively), but was maintained at pre-intervention levels in LCHF. HCHO and PCHO groups improved times for 10 km race walk: 6.6% (90% CI: 4.1, 9.1%) and 5.3% (3.4, 7.2%), with no improvement (−1.6% (−8.5, 5.3%)) for the LCHF group. In contrast to training with diets providing chronic or periodised high-CHO availability, and despite a significant improvement in
tjp12142-math-0004.png
, adaptation to the topical LCHF diet negated performance benefits in elite endurance athletes, in part due to reduced exercise economy.