Glycemic index, load, and insulin response

Glycemic index refers to the potential of a food to raise blood glucose levels. This value may be a useful tool to benefit people with diabetes management and those desiring weight loss for improving health, aesthetics, longevity, and quality of life. Pure glucose has a glycemic index of one hundred. Foods are classified as high, moderate, or low based on this comparison. A high glycemic index is seventy or above. Moderate is fifty-five to seventy. Low is fifty-five or below. The glycemic index was once thought to demonstrate quality of carbohydrates. The prevailing thought was to avoid simple sugars and carbohydrates and consume more complex carbohydrates. Complex carbohydrates can have a high variability in glycemic index, glycemic load, and insulin response. In studies, many times the exact same food has had a variable glycemic index. The glycemic index was developed to classify foods solely on the ability to raise blood glucose levels using glucose itself as reference point. Therefore, carbohydrates with a high glycemic index are those digested, absorbed, and metabolized quickly to increase blood glucose. Lower glycemic index foods are those that are obviously digested, absorbed, and metabolized more slowly for a more gradual increase in blood glucose. Glycemic index is a good tool for healthcare professionals, but does not tell the entire story regarding health, weight loss and diabetes management. For example, a baked white potato has higher glycemic index than French fries. Which is healthier and is more beneficial for weight loss and diabetes management? This is not a trick question. The answer is obvious.  

 

Glycemic load may provide a more comprehensive story than glycemic index alone. Glycemic load uses glycemic index, but also considers the amount of carbohydrate that are yielded by a serving of food. Glycemic load uses glycemic index expressed as a percentage multiplied by the amount of carbohydrates supplied by the serving of food. On this scale, a value of twenty or greater is considered high. From ten to twenty is considered moderate and a value under ten is low. This approach provides a more beneficial number by the use of both variables for weight loss and diabetes management.  For example, the glycemic index for a medium doughnut and watermelon is seventy-six, but the carbohydrate yield for one serving of watermelon is eleven grams while a medium doughnut has twenty-three grams. The healthier choice is obvious in this example regardless of glycemic index. Although healthy food choices demonstrate a low glycemic index, this may not hold true always. Some moderate to high glycemic index foods may still be beneficial for weight loss and diabetes management. A few of these foods include honey, pineapple, white wheat bread, and watermelon. Two table spoons of sucrose or table sugar has a lower glycemic load than many breakfast cereals. 

 

Being a juvenile onset diabetic since age five, I am very aware of carbohydrate count and glycemic index. But maybe more important to me, how does this relate to insulin response? Weight loss and diabetes management are directly affected by blood sugar levels and insulin response. Blood sugar levels such as hyperglycemia or high blood sugar and hypoglycemia or low blood sugar are a result of the hormone insulin by either release, binding site affinity, or administration. All these factors have a role in blood sugar control as well as diet and exercise. Diet and exercise certainly affect these factors profoundly. Insulin allows glucose to pass from the bloodstream into the cells of the body to carry out normal physiological function. Insulin is generally considered a storage hormone that promotes glycogen stores within muscle cells and substrates to adipose tissue for fat deposition.  For this reason, diabetes management and weight loss are benefitted by lowering insulin levels and resistance. Weight loss and diabetes management regimens are benefitted by reducing daily caloric intake, high glycemic load carbohydrates, insulin production, and resistance. Although limited research exists on direct insulin response to various foods and timing, a common-sense approach would suggest that lowering insulin levels could provide significant benefit. It is well documented that continual consumption of high glycemic load foods will lead to increased insulin production due to greater insulin resistance. The reduction in insulin resistance and production is achieved by eating foods that are less than ten on the glycemic load scale. 

 

It has been documented through research that low or reduced fat products generally have a higher insulin production response. This makes sense physiologically because fat is known to delay stomach emptying, takes longer to breakdown than other substrates, and slows motility through the gastrointestinal tract. Therefore, foods higher in fat may in some cases have a lower insulin response. The higher fat foods may help lower insulin response and resistance, but may also cause other adverse effects on the body. Limited research also suggests that lower glycemic load foods eaten earlier in the day produces less insulin resistance and production than later in the evening.  It therefore may be beneficial to eat meals denser in starchy or complex carbohydrates earlier in the day and fibrous or low glycemic load carbohydrates in the evening. These suggestions are based solely on insulin response data collected.  No investigation or suggestion are available for people working alternate work schedules. 

 

In conclusion, Diabetic and weight management depends on daily caloric intake, percentages of macronutrients ingested, food choices, and caloric expenditure. Daily caloric intake will eventually produce the desired bodyweight for the individual. Percentages of macronutrients consumed determine how the body is sculpted. Food choices will promote or hinder results, health, and energy level.  The foods chosen should be low glycemic load foods to reduce insulin resistance and promote insulin efficiency.  Caloric expenditure will control the speed and aesthetics of the desired results. Healthy and well-designed diabetes or weight management programs require a multifactorial approach. Drastically manipulating certain macronutrients, unstructured exercise that is not tailored to any specific goals, or hormonal manipulation with a magical supplement are not particularly beneficial for long term results and in some cases can be dangerous. Please educate to empower yourself, eat smart, and visit tpnbodyperfect.com for more articles and information.