Effect of short-duration lipid supplementation on fat oxidation during exercise and cycling performance

Abstract

The effect of intramyocellular lipids (IMCLs) on endurance performance with high skeletal muscle glycogen availability remains unclear. Previous work has shown that a lipid-supplemented high-carbohydrate (CHO) diet increases IMCLs while permitting normal glycogen loading. The aim of this study was to assess the effect of fat supplementation on fat oxidation (Fox) and endurance performance. Twenty-two trained male cyclists performed 2 simulated time trials (TT) in a randomized crossover design. Subjects cycled at ∼53% maximal voluntary external power for 2 h and then followed 1 of 2 diets for 2.5 days: a high-CHO low-fat (HC) diet, consisting of CHO 7.4 g·kg(-1)·day(-1) and fat 0.5 g·kg(-1)·day(-1); or a high-CHO fat-supplemented (HCF) diet, which was a replication of the HC diet with ∼240 g surplus fat (30% saturation) distributed over the last 4 meals of the diet period. On trial morning, fasting blood was sampled and Fox was measured during an incremental exercise; a ∼1-h TT followed. Breath volatile compounds (VOCs) were measured at 3 time points. Mental fatigue, measured as reaction time, was evaluated during the TT. Plasma free fatty acid concentration was 50% lower after the HCF diet (p < 0.0001), and breath acetone was reduced (p < 0.05) "at rest". Fox peaked (∼0.35 g·kg(-1)) at ∼42% peak oxygen consumption, and was not influenced by diet. Performance was not significantly different between the HCF and HC diets (3369 ± 46 s vs 3398 ± 48 s; p = 0.39), nor were reaction times to the attention task and VOCs (p = NS for both). In conclusion, the short-term intake of a lipid supplement in combination with a glycogen-loading diet designed to boost intramyocellular lipids while avoiding fat adaptation did not alter substrate oxidation during exercise or 1-hour cycling performance.

Breath acetone to monitor life style interventions in field conditions: An exploratory study

“…Breath acetone has been known for decades to increase several fold in diabetes ketoacidosis . Recent improvement in gas metabolites analysis has allowed the detection of smaller increases in breath acetone, which may correspond to changes in hepatic ketogenesis within the physiological range, in healthy subjects during strenuous physical exercise . Since hepatic ketogenesis closely parallels whole‐body lipid oxidation , we propose that breath acetone may be used to monitor lifestyle interventions targeted to stimulate fat oxidation.…”

Changes in muscle strength and endurance of professional cyclists due to PycnoRacer^TM

“…Recovery from fatigue after high-intensity training is important for improving the performance of athletes. There are many reports analyzing cyclist fatigue using blood data, including metabolites such as lactate concentration, C-reactive protein, and creatine kinase, in addition to maximum oxygen intake [19][20][21][22] . However, no study has analyzed the muscular fatigue of cyclists from the viewpoint of local muscle performance.…”

Efficacy of Popular Diets Applied by Endurance Athletes on Sports Performance: Beneficial or Detrimental? A Narrative Review

“…Besides these ketogenic diet applications, acute [30][31][32][33][34][35][36][37][38][39] or long-term [130] administration of KBs (in a ketone ester (KE) or ketone salt (KS) form) and CHO restoration following keto-adaptation [26,[40][41][42][43][45][46][47] have also been evaluated in endurance athletes. Additionally, studies have been conducted to investigate the effects of an acute pre-exercise high-fat meal [51], and a short-term (1.5 days) fat supplementation during high-CHO diet administration [49,50]. In this section, we will discuss these high-fat studies in detail, with all their beneficial and harmful consequences for endurance athletes.…”

“…High-fat diet administration has taken place in endurance athletes with the aim of improving the utilization of fatty acids and KB [14,19,20,[24][25][26]28,[32][33][34][35][36][41][42][43][45][46][47][49][50][51], sparing muscle glycogen stores [24,37,42,44,46,47], increasing weight loss, especially body fat mass [14,19,21,28], improving aerobic capacity [28], improving time to exhaustion [26,51] and time-trial performance [33,46,131], regulating performance-related parameters [34,36,39], increasing cognitive performance [38], regulating exercise-associated immunologic and hormonal response [15,22,30], increasing cellular gene expression [132], and attenuating overreaching syndrome [130].…”