Amount and Type of Dietary Fat, Postprandial Glycemia, and Insulin Requirements in Type 1 Diabetes: A Randomized Within-Subject Trial

Abstract

The American Diabetes Association recommends individuals with type 1 diabetes (T1D) adjust insulin for dietary fat; however, optimal adjustments are not known. This study aimed to determine 1) the relationship between the amount and type of dietary fat and glycemia and 2) the optimal insulin adjustments for dietary fat. RESEARCH DESIGN AND METHODS Adults with T1D using insulin pump therapy attended the research clinic on 9-12 occasions. On the first six visits, participants consumed meals containing 45 g carbohydrate with 0 g, 20 g, 40 g, or 60 g fat and either saturated, monounsaturated, or polyunsaturated fat. Insulin was dosed using individual insulin/carbohydrate ratio as a dual-wave 50/50% over 2 h. On subsequent visits, participants repeated the 20-60-g fat meals with the insulin dose estimated using a model predictive bolus, up to twice per meal, until glycemic control was achieved. RESULTS With the same insulin dose, increasing the amount of fat resulted in a significant dose-dependent reduction in incremental area under the curve for glucose (iAUC glucose) in the early postprandial period (0-2 h; P = 0.008) and increase in iAUC glucose in the late postprandial period (2-5 h; P = 0.004). The type of fat made no significant difference to the 5-h iAUC glucose. To achieve glycemic control, on average participants required dual-wave insulin bolus: for 20 g fat, +6% insulin, 74/26% over 73 min; 40 g fat, +6% insulin, 63/37% over 75 min; and 60 g fat, +21% insulin, 49/51% over 105 min. CONCLUSIONS This study provides clinical guidance for mealtime insulin dosing recommendations for dietary fat in T1D. The impact of dietary fat on glycemia has been highlighted by those living with type 1 diabetes (T1D) who, despite accurate carbohydrate counting, have found glycemic control difficult to achieve when consuming high-fat meals. Clinical research supports their experience, with dietary fat having been shown to modulate the postprandial glucose response in all seven studies included in a recent systematic review (1). We have previously shown that in adults with T1D, the addition of both fat and protein to a

Insulin Dosing for Fat and Protein: Is it Time?

“…Very few studies have addressed the duration and split of the combination bolus. New data reported in this issue (6) show the optimal duration of the combination bolus increases with fat amount, from 73 min for 20 g of fat (75%/25%) to 105 min for 60 g of fat (50%/50%). The findings provide support for recommendations (18,19) that a greater proportion of the total insulin dose needs to be given up front ($50%) over a shorter duration (,2 h) than previously thought.…”

“…There is a need for an evidence-based, safe, and practical method to guide insulin adjustments for high-fat, high-protein meals. In this issue of Diabetes Care, Bell et al (6) address the pressing clinical question of optimal insulin adjustments for meals containing differing amounts of dietary fat. This is important because postprandial hyperglycemia has been identified as a risk factor for the development of long-term complications of diabetes (7), and higher fat diets have increased in popularity in recent years.…”

“…A number of studies have previously investigated the additional insulin required for fat and protein (4, 12,15,16,17), with all reporting marked interindividual differences. In their initial study using the same model predictive algorithm, Bell et al (6) found that for a pizza meal a dose increase of 65% was needed to prevent hyperglycemia, with the majority of participants requiring an extra 75-124% of their usual dose (4). Wolpert et al (12) found that a high-fat meal required on average 42% more insulin than a low-fat meal, with someparticipantsrequiringmorethantwice as much insulin while others required no extra insulin (217% to 108%).…”

Acute Effect of Pistachio Intake on Postprandial Glycemic and Gut Hormone Responses in Women With Gestational Diabetes or Gestational Impaired Glucose Tolerance: A Randomized, Controlled, Crossover Study

“…In consistent with previous findings, our data showed that the serum glucose and insulin levels in both GIGT and GDM were not changed within 2 h after pistachio intake while isocaloric WWB led to significant increase of blood glucose and insulin levels. Previous clinical study also reported that increase of fat intake with controlled carbohydrate amount showed a dose dependent reduction of blood glucose with same insulin doses (19). Kendall et al also showed that better postprandial glucose responses in subjects of metabolic syndromes after pistachio intake compared to white bread intake, with equal carbohydrate content (12).…”

Real-world data on the use of insulin glargine 300 U/mL in Japanese patients with type 1 diabetes: twelve-month results from a post-marketing surveillance study (X-STAR study)

“…Traditionally, carbohydrate counting, calculating dose of bolus insulin based on estimation of carbohydrate intake, has been recommended [3]. Recently, it has been suggested that, besides carbohydrate, both protein and fat are also important parameters for predicting postprandial plasma glucose [19,20]. Further improvement of prediction models may help T1D patients achieve glycemic target.…”