Does Dietary Fat Impact Blood Sugars?

Carb Counting and Exchanges

The American Diabetes Association currently promotes the teaching and utilization of carbohydrate counting (formerly exchange lists) as an effective means of managing diabetes.  [Of course it is important to remember that diet works in conjunction with medication for diabetes management.]  For those with type I diabetes who are not producing any insulin, the carbohydrate content of that meal is used to calculate the amount of insulin to be given exogenously.

Carb counting oversimplified: When the body breaks down a meal, the amount of carbohydrate within that meal drives blood sugar levels.  Managing the amount of carbohydrate consumed (ex. eating 60 grams vs 95 grams) leads to better blood glucose management.  

While the overarching principle is true, carb counting does not take into account protein or fat in that given meal, as those two macronutrients do not break down to sugar (directly).  So does fat eaten at that same meal impact blood sugars?  Evidence is starting to show us that free fatty acids circulating in the blood impair insulin sensitivity.

Research Brief

In a new article published in Diabetes Care (November 2012), researchers used a crossover design to follow seven people with Type I Diabetes and had them eat a high fat meal and low fat meal with identical carbohydrate content.  Using an artificial pancreas to monitor BG response over the next 18 hours, the high fat meal required higher insulin infusion than the low fat meal, and despite the higher insulin delivery, led to increased hyperglycemia (high blood sugar).

While this study is hardly enough to draw any sweeping conclusions, it is another step in the direction of understanding the impact of the total diet on diabetes management.  With more research it may lead to changes in dietary recommendations, carb counting, or even insulin algorithms.  

If you want to read the article in more detail please check out the abstract here!