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Objective: The aim of this study was to measure the glycemic index (GI) values of five Cinch™ products, using pure glucose sugar as the reference food.

Methods: This study was conducted using internationally recognized GI methodology which has been validated by results obtained from large multi-center research trials. A group of 10 healthy, non-smoking people, aged between 18-45 years, was recruited from the staff and student population of the University of Sydney for each part of the study. People volunteering to participate in the study were excluded if they: were over or underweight; were dieting; had impaired glucose tolerance; were suffering from any illness or food allergy; or were regularly taking prescription medication other than standard contraceptive medication.

The study, the reference food and the test foods were served to the subjects in fixed test portions containing 50 grams of digestible (available) carbohydrate. Subjects consumed the reference food on three separate occasions and each of the test foods on one occasion only. Each session was completed on a separate morning with at least one day in between subsequent sessions. The night before each test session, the subjects ate a regular evening meal and then fasted for at least 10 hours overnight. The following morning, after fasting blood samples were taken from each subject, each was given a fixed portion of the reference food or a test food, which they consumed with 250 grams of plain water at a comfortable pace within 12 minutes. Blood samples were collected at baseline and 15, 30, 45, 60, 90 and 120 minutes after eating had commenced.

A two-hour blood glucose response curve was constructed for each subject’s reference food and test food sessions using the plasma glucose concentrations for each of their eight blood samples. The area under each two-hour plasma glucose curve (AUC) was then calculated in order to obtain a single number, which expresses the total increase in plasma glucose in that subject as a result of ingesting that food during the two-hour period. A glycemic index (GI) value for each test product was then calculated for each subject by dividing their two-hour blood glucose AUC values for each test food by their average two-hour blood glucose AUC value for the reference food and multiplying by 100 to obtain a percentage value.

Results/Discussion: Cinch™ products tested in this study produced GI values ranging from 16 – 29, placing all these products well within the low GI category. The low GI values produced by the two Shaklee weight management shake powders largely reflect the GI response of their main component carbohydrate, fructose (GI = 19), in combination with other ingredients known to help delay gastric emptying and carbohydrate digestion, such as soy protein isolate and various dietary fiber gums. The slight differences observed between the GI values for the three Shaklee bars tested in this study reflect the slight variations in the fat, protein and sugar contents of their equal carbohydrate test portions. The bars’ relatively high protein contents and the presence of lower GI ingredients, such as fructose are some of the factors responsible for their lower GI responses. Note: Glycemic Index values of 55 or less are considered low GI foods, values between 56-69 are considered medium GI foods and values greater than 70 are considered high GI foods.

GI values are measured using portions of foods and drinks that contain between 25 – 50 grams of digestible carbohydrate, but these may not be representative of the typical serving sizes consumed by people in normal environments. Glycemic load (GL) accounts for portion size of a carbohydrate-containing food in combination with the GI Value. The GL value for a food or drink is calculated by multiplying the amount of available carbohydrate in the portion of the food or drink by its GI value and then dividing by 100.

Similar to GI values, GL values are useful for helping people identify which types and amounts of foods will produce relatively lower blood glucose responses after consumption – an important consideration for people with diabetes and at risk of developing it. Currently, the consensus is that GL values of 10 or less are low GL; GL values between 11 – 19 are medium GL values; and GL values of 20 or more are high GL values. As depicted in the graph below, all five Cinch™ products tested in this study produced GL values ranging from 2.6 – 6.4, which places these products in the low GL category. Note: Glycemic Load values of 10 or less are considered low foods, values between 10-20 are considered medium GI foods and values greater than 20 are considered high GI foods.

Conclusion: This study confirms that the Cinch™ products tested are low glycemic, deliver a low glycemic load and elicit a low glycemic response. Given the benefits of lower glycemic foods in weight control, these results suggest that Cinch™ bars and shakes may be helpful to those trying to achieve a healthy bodyweight.