Carbohydrate counting may be “the gold standard for improving glycemic control,” but the new food insulin index can work much better. For people with diabetes this index is also a more comprehensive guide to blood sugar control than the glycemic index.
For years the limitation of the food insulin index (also known as just the insulin index) was the few foods tested. The original 1997 study, which in 2003 I reviewed in detail for the first time in the article “Insulin Index”on my personal website, tested only 38 foods.
We had to wait until 2011 for the index to grow to about 120 foods in “Prediction of postprandial glycemia and insulinemia in lean, young, healthy adults.” I reviewed that study here at “Manage Your Blood Sugar Better with the Insulin Index.”
Now, a much more extensive study of the food insulin index is available, and it is further expanded to include 26 more tested foods. The study, titled “Clinical Application of the Food Insulin Index to Diabetes Mellitus,” is Kirstine Bell’s Ph.D. dissertation from Australia’s University of Sydney. The entire 282-page dissertation plus a dozen appendices is free online.
These are the foods most recently tested for their food insulin index:
It’s no coincidence that Kirstine Bell’s Ph.D. comes from the University of Sydney. That’s where Professor Jennie Brand-Miller was Bell’s supervisor has led much of the world’s research of both the insulin and glycemic indexes for more than two decades.
Carb Counting Doesn’t Help
One of the most significant findings to come out of Bell’s work is that carbohydrate counting simply doesn’t work well enough. She led a systematic review and meta-analysis of the “Efficacy of carbohydrate counting in type 1 diabetes.” The study found “no significant improvement in A1C with carbohydrate counting over general dietary advice and/or usual care.”
Earlier studies show that using the glycemic index does help us improve our A1C levels. I know it too from my own experience of using the GI for years. But that index shows us only the blood sugar effect of carbohydrates. The GI ignores the effects of the other two macronutrients, protein and fat.
Effects of Protein and Fat on Blood Sugar
Bell’s work helps us fine-tune our understanding of the effects of protein in particular. When our bodies don’t produce enough insulin, protein can raise our blood sugar level. “In the absence of sufficient exogenous insulin in people with type 1 diabetes,” she writes, “it has been shown that protein can raise the blood glucose level.”
On the other hand, when we eat fat along with carbohydrate, this “results in lower blood glucose levels and significantly higher insulin levels compared with those following carbohydrate ingestion alone.”
Compared with about 2,500 foods tested for their glycemic index, those tested for their food insulin index are few indeed. But, Bell writes that “The tested foods included the top 100 sources of energy in the American diet, representing 10 food categories.”
Applying the Insulin Index to People with Type 1 and Type 2 Diabetes
High levels of insulin in our blood after eating “is not the response to a single nutrient (carbohydrate) but rather the sum total effect of metabolic interactions among different nutrients within foods,” Bell writes. Consequently, her dissertation includes randomized study of people with type 1 and type 2 diabetes:
A study of 26 adults with type 1 diabetes who use insulin pumps compared traditional carb counting with using the insulin index. In this 12-week study blood sugar levels were similar, but those in the insulin index group tended to have a lower risk of hypoglycemia.
The first real-world study of 10 adults with type 2 diabetes consumed either a high insulin index or a low insulin index diet. The results showed an impressive 41 percent reduction in the predicted insulin demand.
Like the glycemic index, we can’t accurately calculate a food’s insulin index based on the nutrients it has. This makes the complete database of 147 foods tested for their food insulin index currently the best guide we have to managing our blood sugar.
See more of my articles about how to manage diabetes: