Nutrition, exercise and muscle metabolism in obesity
Research type
Research Study
Full title
Influence of pre- or post-exercise food intake on muscle metabolism in obesity
IRAS ID
173313
Contact name
Scott L Robinson
Contact email
Clinicaltrials.gov Identifier
Duration of Study in the UK
1 years, 0 months, 1 days
Research summary
Obesity is a major public health issue as it greatly increases risk for cardiovascular disease and type 2 diabetes (cardio-metabolic diseases). Part of the problem is that obesity is associated with insulin resistance. Insulin resistance is a condition where there is resistance to the normal effects of the hormone insulin in lowering blood sugar levels (e.g., after eating a sugary meal). This can lead to continually high blood sugar levels that can be detrimental to many tissues in the body. Insulin resistance is often regarded as a causative factor in the development of cardio-metabolic disease.
Athletes perform regular exercise training and are characterised by high insulin sensitivity (the opposite of insulin resistance). This is in part because regular exercise in athletes promotes the use of intramuscular fat (i.e., fat stored within muscle cells) as a fuel for exercise, and because exercise training causes adaptations to the exercised muscles to increase muscle fitness. Exercise training is recommended for obese populations, but studies indicate aerobic exercise training in obese individuals in the absence of significant weight loss has minimal impact on insulin resistance. We believe that studies of exercise training in obese individuals have failed to sufficiently stimulate the use of muscle fat as a fuel during exercise or promote sufficient improvements in muscle fitness to enhance insulin sensitivity because they have not considered the important role that nutrition can play in influencing these responses. For example, it is known that performing exercise after eating (the fed state) versus performing exercise before eating can blunt these adaptive responses to exercise in lean individuals.
Therefore, we will investigate the hypothesis that a single bout of aerobic exercise performed in the overnight-fasted versus fed-state can stimulate greater muscle fat use during exercise in obese individuals. We will also assess whether overnight-fasted versus fed-state exercise results in enhanced expression of genes related to improvements in muscle fitness. The expected outcomes will help to determine if exercising in the overnight-fasted state could be used to optimise adaptation to training in these obese individuals. The future impact of this research could be the recommendation of a simple nutritional strategy considering meal timing to enhance the effects of aerobic exercise training in obese individuals, with potential long-term benefits for reducing insulin resistance and cardio-metabolic disease risk.
REC name
West Midlands - Black Country Research Ethics Committee
REC reference
15/WM/0128
Date of REC Opinion
18 May 2015
REC opinion
Further Information Favourable Opinion