Here you are. Dietary fat raises blood sugar:

Here’s the study it was based on:

Dietary Fat Acutely Increases Glucose Concentrations and Insulin Requirements in Patients With Type 1 Diabetes, Diabetes Care, April 2013

Each person had a chance to eat the high-fat meal and the low-fat meal. When they ate the high-fat meal they needed more insulin to cover the same amount of carbohydrate. The meals had identical carbohydrate and protein, but different fat content (60 grams vs. 10 grams).