Glucose Tolerance Test: Here’s What This Simple & Powerful Test Can Show You

A glucose tolerance test can tell you a lot about your glycemic control, your ability to metabolize sugars and carbohydrates. Your glycemic control is a BIG part of what makes up your Metabolic Type.

A Glucose Tolerance Test involves the administration of 44 grams of glucose (about half of what is used by conventional glucose tests) in 12 ounces of water and then tracking your blood sugar with a glucose meter during various intervals over a 90-minute period. The results can yield a tremendous amount of insight into your dominant metabolic functions. With this method, it is also advised to administer 5 grams of Cream of Tartar (a common form of powdered potassium) with the glucose drink.

What a Glucose Tolerance Test Can Tell You

A glucose tolerance test will tell you your body’s reactivity to carbohydrates among other things. Because of the highly individual nature of metabolism, a food and nutrient will behave very differently in people’s bodies.

The results of a glucose tolerance test can help determine your Metabolic Type. Your Metabolic Type is the true means for understanding what foods and nutrients your body has the greatest need for. Your Metabolic Type is determined by the identification of your most dominant metabolic processes, either cellular oxidative or one of the branches of the Autonomic Nervous System (sympathetic/parasympathetic).

Let’s say your glucose tolerance test revealed a highly reactive response to 44 grams of glucose and 1 gram of potassium. Typically an immediate rise in blood sugar followed by a significant decrease in blood sugar after 45-75  minutes indicates a very inefficient metabolic reaction to glucose and carbohydrates.

This person is characterized as a ‘fast oxidizer’, indicating there is a greater need for protein and fat in the diet and less of a need for carbohydrates. This is because a fast oxidizer is overly reliant on their metabolism of carbohydrates while their opposite metabolic system, their fat metabolism, is under-reactive in comparison. Typical also among fast oxidizers is an acidifying reaction to 1 gram of potassium. Their saliva will become more acid and the urine more alkaline. Also seen as an acidifying reaction to potassium and glucose is a relative increase in blood pressure and pulse rate.

In an opposite type of scenario, a slow blood sugar reaction to glucose is typical among slow oxidizers. A typical pattern reveals a slight increase in blood sugar followed by a slow tapering off of blood sugar over 75 minutes. For slow oxidizers, the potassium similarly results in an acid reactions like the fast oxidizer, but this is a necessary reaction for the slow oxidizer because the slow oxidizer tends to be too alkaline.

Besides the blood sugar and biochemical reactions of the Oxidative Metabolic Types, there are also different reactions that occur for Autonomic Dominant Metabolic Types (sympathetic/parasympathetic/balanced). An autonomic dominant type is more reactive to potassium than just the glucose. An autonomic dominant typically is more dependent on the nervous system’s response to glucose and potassium, rather than the intracellular, oxidative metabolic processes.

A sympathetic dominant will have a similar reaction to glucose that the slow oxidizer has but the potassium will tend to produce an alkaline reaction. A parasympathetic type will tend to have a similar glucose curve that the fast oxidizer has but the potassium will tend to make the parasympathetic type too alkaline, and physiological changes reflect this, particularly decreases in blood pressure, and respiration rate.

Someone characterized as a Mixed Type will typically have a variable reaction to the test, as the results will shift depending on the time of the day.

A glucose tolerance test is one part of how to identify a person’s metabolic type. Personally, I recommend people that I work with use it on themselves to get a good sense about their carbohydrate tolerance.