Training in the fasted state improves glucose tolerance during fat‐rich diet

A fat‐rich energy‐dense diet is an important cause of insulin resistance. Stimulation of fat turnover in muscle cells during dietary fat challenge may contribute to maintenance of insulin sensitivity. Exercise in the fasted state markedly stimulates energy provision via fat oxidation. Therefore, we...

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Bibliographic Details
Published in:The Journal of physiology 2010-11, Vol.588 (21), p.4289-4302
Main Authors: Van Proeyen, Karen, Szlufcik, Karolina, Nielens, Henri, Pelgrim, Koen, Deldicque, Louise, Hesselink, Matthijs, Van Veldhoven, Paul P., Hespel, Peter
Format: Article
Language:English
Subjects:
Body Composition - physiology
Dietary Fats - metabolism
Exercise - physiology
Fasting - physiology
Fatty Acids, Nonesterified - blood
Glucose - metabolism
Glycogen - metabolism
Humans
Insulin Resistance - physiology
Lipid Metabolism - physiology
Male
Muscle, Skeletal - metabolism
Physical Endurance - physiology
Skeletal Muscle and Exercise
Young Adult
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Summary:A fat‐rich energy‐dense diet is an important cause of insulin resistance. Stimulation of fat turnover in muscle cells during dietary fat challenge may contribute to maintenance of insulin sensitivity. Exercise in the fasted state markedly stimulates energy provision via fat oxidation. Therefore, we investigated whether exercise training in the fasted state is more potent than exercise in the fed state to rescue whole‐body glucose tolerance and insulin sensitivity during a period of hyper‐caloric fat‐rich diet. Healthy male volunteers (18–25 y) received a hyper‐caloric (∼+30% kcal day−1) fat‐rich (50% of kcal) diet for 6 weeks. Some of the subjects performed endurance exercise training (4 days per week) in the fasted state (F; n= 10), whilst the others ingested carbohydrates before and during the training sessions (CHO; n= 10). The control group did not train (CON; n= 7). Body weight increased in CON (+3.0 ± 0.8 kg) and CHO (+1.4 ± 0.4 kg) (P < 0.01), but not in F (+0.7 ± 0.4 kg, P= 0.13). Compared with CON, F but not CHO enhanced whole‐body glucose tolerance and the Matsuda insulin sensitivity index (P < 0.05). Muscle GLUT4 protein content was increased in F (+28%) compared with both CHO (P= 0.05) and CON (P < 0.05). Furthermore, only training in F elevated AMP‐activated protein kinase α phosphorylation (+25%) as well as up‐regulated fatty acid translocase/CD36 and carnitine palmitoyltransferase 1 mRNA levels compared with CON (∼+30%). High‐fat diet increased intramyocellular lipid but not diacylglycerol and ceramide contents, either in the absence or presence of training. This study for the first time shows that fasted training is more potent than fed training to facilitate adaptations in muscle and to improve whole‐body glucose tolerance and insulin sensitivity during hyper‐caloric fat‐rich diet. Increasing levels of obesity, arising from high‐fat energy‐rich diets and sedentary lifestyles, are driving a global pandemic of type 2 diabetes. It is well known that exercise training can prevent and/or treat insulin resistance, a major factor in the development of type 2 diabetes. However, in most individuals, time availability for exercise training is scarce, or motivation to spend many hours in training is lacking, which underlines the importance of improving training intervention strategies. This study demonstrates for the first time that during a hyper‐caloric fat‐rich diet in healthy young men, early morning exercise in the fasted state is more potent th
ISSN:0022-3751
1469-7793
DOI:10.1113/jphysiol.2010.196493