*Review* **Islet Health, Hormone Secretion, and Insulin Responsivity with Low-Carbohydrate Feeding in Diabetes**

#### **Cassandra A. A. Locatelli 1,2 and Erin E. Mulvihill 1,2,3,4,\***


Received: 1 October 2020; Accepted: 7 November 2020; Published: 11 November 2020

**Abstract:** Exploring new avenues to control daily fluctuations in glycemia has been a central theme for diabetes research since the Diabetes Control and Complications Trial (DCCT). Carbohydrate restriction has re-emerged as a means to control type 2 diabetes mellitus (T2DM), becoming increasingly popular and supported by national diabetes associations in Canada, Australia, the USA, and Europe. This approval comes from many positive outcomes on HbA1c in human studies; ye<sup>t</sup> mechanisms underlying their success have not been fully elucidated. In this review, we discuss the preclinical and clinical studies investigating the role of carbohydrate restriction and physiological elevations in ketone bodies directly on pancreatic islet health, islet hormone secretion, and insulin sensitivity. Included studies have clearly outlined diet compositions, including a diet with 30% or less of calories from carbohydrates.

**Keywords:** low carbohydrate diet; ketogenic diet; insulin sensitivity; pancreas; islet of Langerhans
