IS-PM05 - High-carbohydrate or high-fat diets for optimizing training adaptation and performance?

INVITED SESSION: (IS-PM05) - High-carbohydrate or high-fat diets for optimizing training adaptation and performance? [Applied track]
Date: 03.07.2019
Lecture room: Congress Hall
Time: 14:00 - 15:30

Chair(s): JØRN WULFF HELGE - UNIVERSITY OF COPENHAGEN / DENMARK

Speakers:

1. TRAINING-DIET INTERACTIONS TO OPTIMIZE SKELETAL MUSCLE ADAPTATION
HAWLEY, J. / AUSTRALIA

ABSTRACT:
Traditional nutritional approaches to endurance training have typically promoted high carbohydrate (CHO) availability before, during and after training sessions to ensure adequate muscle substrate to meet the demands of daily training. However, during the past decade, data from several laboratories have demonstrated that deliberately training in conditions of reduced CHO availability can promote training-induced adaptations of human skeletal muscle (i.e. increased maximal mitochondrial enzyme activities and/or mitochondrial content, increased rates of lipid oxidation and, in some instances, improved exercise capacity). Indeed, there has been widespread interest from athletes, coaches and sport scientists regarding the potential benefits of high-fat, low- carbohydrate diets when training for and competing in endurance events lasting up to 3 h. Despite this renewed interest in high-fat, low-CHO diets for endurance sport, fat-rich diets do not improve training capacity or performance, but directly impair rates of muscle glycogenolysis and energy flux, limiting high-intensity ATP production. When highly trained athletes compete in endurance events lasting up to 3 h, CHO-, not fat-based fuels are the predominant fuel for the working muscles and CHO, not fat, availability becomes rate limiting for performance.
________________________________________________________________________________________________

2. MAXIMIZING FAT OXIDATION: HELP OR HINDRANCE TO ADAPTATION & PERFORMANCE?
HELGE, J. / DENMARK

ABSTRACT:
Endurance training promotes an upward and rightward shift of the fat oxidation during exercise across increasing relative exercise intensities and this is generally believed to potentiate endurance performance of longer duration, through a decreased muscle glycogen utilization. In line with this major focus has over the last decade been specifically directed towards measuring maximal fat oxidation and how this is linked to endurance performance. In one study we found a direct independent association, albeit not very strong, between ironman triathlon performance and maximal fat oxidation (1). Although the evidence is somewhat limited, one part of this talk will focus on the role of maximal fat oxidation for endurance performance.
Recent years has seen a renewed interest in diet and exercise manipulations and in particular high fat and/or ketogenic diets that are directed towards maximising fat oxidation and thus hypothetically optimises substrate utilization. Interestingly, we observed an attenuated maximal fat oxidation after 14 days extreme prolonged cycle exercise in well trained, albeit somewhat older, men (2). Although there is not an overwhelming number of studies, the second part of this talk will based on these studies focus on how adaptation to training and/or diet affects maximal fat oxidation.
________________________________________________________________________________________________

3. ADAPTATION TO HIGH FAT DIETS AND ENDURANCE PERFORMANCE IN ELITE ATHLETES
BURKE, L. / AUSTRALIA

ABSTRACT:
This talk will focus on evidence supporting or disputing the effects of strategies to adapt to high fat diets on the performance of elite endurance athletes. Although it is difficult to undertake controlled studies on elite athletes to investigate all the testimonials or hypotheses around different protocols, this presentation will examine the available data on performance, movement economy, metabolism and health. The suitability of these protocols will be examined in the context of various types of endurance events and endurance athletes. Furthermoe, other issues relating to the health and training capacity of endurance athletes will be explored.