Metabolic Testing

Glycaemic response (GR) refers to the trajectory of the post-prandial (after eating) blood glucose curve. This allows the comparison between products at specific time points which may have important clinical implications. This is distinct from glycaemic index (GI) in that while the GI refers to the ranking of foods according to the extent to which a food raises blood sugar levels after ingestion, glycaemic response measures the rate of response and allows for comparisons between foods with the same glycemic index.

This testing is usually carried out in conjunction with glycaemic response and looks at the change in insulin in blood after consuming a food product. Insulin is important in the management of blood sugar levels and is necessary for blood sugar to enter the body’s cells where it will be used as energy or stored.

This testing is about how long it takes for food to be emptied from your stomach, which can be effected by a number of factors for example how well food is chewed. The larger the piece of food swallowed the slower the food is emptied from the stomach. Normal gastric emptying after a meal takes around 1 hour 30 mins to 2 hours. While gastric emptying studies are commonly used to investigate digestion and associated conditions they can also be used to explain the effect of glycemic response as the slower rate of the stomach emptying impacts the rate of absoprtion in the small intestines. Certain components in food can increase the time it takes for gastric emptying, and this has been linked with increased satiety and potentially weight loss.

By labelling foods with stable isotopes (most commonly C13), and the using mass spectroscopy techniques to measure the presence of these isotopes for three hours post consumption, it is possible to track the rate of absorption of the isotope, and therefore the food component in to the body. This can be done with both breath and plasma samples.

Diet-induced thermogenesis (DIT) is the amount of energy required for the absorption and metabolism of food and represents 10% of the total energy expenditure.

A number of hormones are realised into the bloodstream in response to food and these can be measured before and after a meal. The levels of a number of these hormones have been shown to correlate with body fat percentage.

A lipid test is a simple blood test which looks at the profile of your blood to identify the amount of different types of fats molecules in your blood. The test specifically looks at the amount of cholesterol and triglycerides in a human participant, either at baseline, or in response to a study product.

This test measures the amount of glucose attached to your haemoglobin. Haemoglobin carries oxygen from your lungs to the rest of your body and is the red coloured part of the blood cell. Red blood cells can live for 100 to 120 days before they are replaced.