Ketones and Muscle Protein Synthesis

The Effects of Acute Nutritional Ketosis on Myofibrillar Protein Synthesis in Young Men

Ketones are natural substances normally produced by the body during prolonged fasting and starvation, or in response to a "ketogenic" diet to be used as fuel by the brain and muscles. Ketones are therefore similar to dietary proteins, carbohydrates and fats since they represent a source of energy for the body. In addition to serving as a source of energy, ketones have also been shown to stimulate increased rates of muscle protein synthesis in humans.

The ingestion of dietary protein is well established to stimulate an increase in the rate of protein synthesis in skeletal muscle. The rate of muscle protein synthesis can be maximized following the intake of 20g of protein. As a result, smaller doses of protein (i.e. 10g) represent a sub-optimal dose of protein because there is still room for improvement concerning muscle protein synthesis.

Recently ketone-containing food products have become available that elevate ketone levels in the body without the need for ketogenic diets or prolonged fasting. Therefore, the purpose of this study is to measure skeletal muscle protein synthesis rates after ingesting the following:

1. Ketone monoester
2. Ketone monoester supplemented with sub-optimal dose of whey protein
3. Sub-optimal dose of whey protein

It is hypothesized that muscle protein synthesis rates will increase following the ingestion of a ketone-containing beverage. Further, muscle protein synthesis rates will be enhanced when the ketone-containing beverage and sub-optimal protein dose are taken together.

Inclusion Criteria:

• Male
• Aged between 18-35 years inclusive
• Healthy, moderately active
• BMI < 30 kg/m2 and > 18.5 kg/m2
• Having given informed consent

Exclusion Criteria:

• Presence of any identified metabolic or intestinal disorders
• Use of tobacco products
• Allergies to milk proteins (whey or casein)
• Lactose intolerance
• Phenylketonuria (PKU)
• A history of neuromuscular problems
• Previous participation in amino acid tracer studies
• Adherence to a strict vegetarian or vegan diet
• Current use of ketone supplements or adherence to a ketogenic diet
• Use of medications known to affect protein metabolism
• Diagnosis of Diabetes
• Engagement in sports or physical exercise 5 or more days per week