Fat adaptation followed by carbohydrate restoration increases AMPK activity in skeletal muscle from trained humans.

  title={Fat adaptation followed by carbohydrate restoration increases AMPK activity in skeletal muscle from trained humans.},
  author={Wee Kian Yeo and Sarah J. Lessard and Zhi-ping Chen and Andrew P. Garnham and Louise M. Burke and Donato A. Rivas and Bruce E. Kemp and John A. Hawley},
  journal={Journal of applied physiology},
  volume={105 5},
We have previously reported that 5 days of a high-fat diet followed by 1 day of high-carbohydrate intake (Fat-adapt) increased rates of fat oxidation and decreased rates of muscle glycogenolysis during submaximal cycling compared with consumption of an isoenergetic high-carbohydrate diet (HCHO) for 6 days (Burke et al. J Appl Physiol 89: 2413-2421, 2000; Stellingwerff et al. Am J Physiol Endocrinol Metab 290: E380-E388, 2006). To determine potential mechanisms underlying shifts in substrate… 

Figures and Tables from this paper

Fat adaptation in well-trained athletes: effects on cell metabolism.

Compared with an isoenergetic CHO diet for the same intervention period, this "dietary periodization" protocol increases the rate of whole-body and muscle fat oxidation while attenuating the rates of muscle glycogenolysis during submaximal exercise.

Intramuscular Mechanisms Mediating Adaptation to Low-Carbohydrate, High-Fat Diets during Exercise Training

This narrative review explores the intramuscular adaptations underlying increases in fat oxidation and decreases in carbohydrate oxidation with LCHF feeding and suggests that the adaptive response driving changes in fat and carbohydrate oxidation lies within the muscle and persists even when the macronutrient content of the diet is altered.

High dietary fat intake increases fat oxidation and reduces skeletal muscle mitochondrial respiration in trained humans

It is demonstrated that high dietary fat intake, rather than low‐CHO intake, contributes to reductions in mitochondrial respiration and increases in whole‐body rates of fat oxidation after a consuming a high‐fat, low‐ CHO diet.

Skeletal muscle metabolic gene response to carbohydrate feeding during exercise in the heat

This study indicates that the provision of exogenous carbohydrate attenuates the stimulation of mRNA expression of UCP3 following exercise in the heat.

Exercise training reverses impaired skeletal muscle metabolism induced by artificial selection for low aerobic capacity.

  • S. LessardD. Rivas J. Hawley
  • Biology
    American journal of physiology. Regulatory, integrative and comparative physiology
  • 2011
The results demonstrate that metabolic impairments resulting from genetic factors (low intrinsic aerobic capacity) can be overcome by an environmental intervention (exercise training) and identify Nur77 as a potential mechanism for improved skeletal muscle metabolism in response to EXT.

High-fat diet overrules the effects of training on fiber-specific intramyocellular lipid utilization during exercise.

It is concluded that a HFD stimulates net IMCL degradation by increasing basal IMCL content during exercise in type I and especially IIa fibers and provides adequate amounts of carbohydrates to maintain high muscle glycogen content during training and does not impair exercise-induced Muscle glycogen breakdown.

Increase of fat utilisation during endurance exercise

There is insufficient scientific evidence to recommend that athletes either ingest fat, in the form of medium-chain triglyceride, during exercise, or "fat-adapt" in the weeks prior to a major endurance event to improve athletic performance.

Training with low muscle glycogen enhances fat metabolism in well-trained cyclists.

Training with low muscle glycogen reduced training intensity and, in performance, was no more effective than training with high muscle glycogens, however, fat oxidation was increased after training with low Muscle glycogen, which may have been due to the enhanced metabolic adaptations in skeletal muscle.

Effects of a Short-Term “Fat Adaptation with Carbohydrate Restoration” Diet on Metabolic Responses and Exercise Performance in Well-Trained Runners

It is suggested that a short-term (six days) FACR diet may facilitate increased fat oxidation and submaximal exercise economy but does not improve 5 km-TT performance.

Fat adaptation science: low-carbohydrate, high- fat diets to alter fuel utilization and promote training adaptation.

  • J. Hawley
  • Environmental Science
    Nestle Nutrition Institute workshop series
  • 2011
Human studies show how low-carbohydrate, fat-rich diets interact with specific contractile stimulus to modulate many of the acute responses to exercise, thereby promoting or inhibiting subsequent training adaptation.



Decreased PDH activation and glycogenolysis during exercise following fat adaptation with carbohydrate restoration.

Results indicate that previously reported decreases in whole body CHO oxidation and increases in fat oxidation after the FAT-adapt protocol are a function of metabolic changes within skeletal muscle.

Intensified exercise training does not alter AMPK signaling in human skeletal muscle.

It is indicated that, in well-trained individuals, short-term HIT improves metabolic control but does not blunt AMPK signaling in response to intense exercise.

Partial restoration of dietary fat induced metabolic adaptations to training by 7 days of carbohydrate diet.

Shift to carbohydrate diet after prolonged adaptation to fat diet and training causes increased resting muscle glycogen levels but impaired leg glucose uptake and similar Muscle glycogen breakdown, despite higher resting levels, compared with when the carbohydrate diet is consumed throughout training.

Low-fat diet alters intramuscular substrates and reduces lipolysis and fat oxidation during exercise.

An extremely low fat (2% of energy) and high-carbohydrate diet lowers whole body lipolysis, total fat oxidation, and nonplasma FA oxidation during exercise in the fasted state in association with a reduced concentration of intramuscular triglyceride.

High-fat diet elevates resting intramuscular triglyceride concentration and whole body lipolysis during exercise.

The marked increase in fat oxidation after a HF diet is associated with elevated IMTG concentration and whole body lipolysis and does not require increased adipose tissue lipolytic and plasma FFA concentration during exercise, suggesting that altered substrate storage in skeletal muscle is responsible for increased fat oxidation during exercise after 2 days of an HF diet.

Intramyocellular lipid stores increase markedly in athletes after 1.5 days lipid supplementation and are utilized during exercise in proportion to their content

IMCL concentrations can be increased during a glycogen loading diet by consuming additional fat for the last 1.5 days of diet, partly in exchange for peripheral fatty acids during subsequent exercise.

Adaptations to short-term high-fat diet persist during exercise despite high carbohydrate availability.

Adaptations to a short-term high-fat diet persisted in the face of high CHO availability before and during exercise, but failed to confer a performance advantage during a TT lasting approximately 25 min undertaken after 2 h of submaximal cycling.

Regulation of metabolic genes in human skeletal muscle by short-term exercise and diet manipulation.

There was a rapid capacity for a short-term exercise and diet intervention to exert coordinated changes in the mRNA transcription of metabolic related genes, and genes involved in glucose regulation are increased following a high-carbohydrate diet.

Influence of muscle glycogen availability on ERK1/2 and Akt signaling after resistance exercise in human skeletal muscle.

The ERK1/2 pathway appears to be unaffected by muscle glycogen content, however, Muscle glycogen availability appears to contribute to regulation of the Akt pathway, which may influence cellular growth and adaptation in response to resistance exercise in a low-glycogen state.

Effect of fat adaptation and carbohydrate restoration on metabolism and performance during prolonged cycling.

These data show significant metabolic adaptations with a brief period of high-fat intake, which persist even after restoration of CHO availability, however, there was no evidence of a clear benefit of fat adaptation to cycling performance.