Do all types of fat have the same effect on insulin sensitivity, the body’s ability to transfer the blood glucose into the cells?

This research evaluated the effect of ingesting either monounsaturated fat, polyunsaturated fat, saturated fat, or water as a control on glucose-stimulated insulin secretion, insulin sensitivity and insulin clearance in seven overweight or obese, non-diabetic participants (Xiao C, et al., 2006).

Olive oil is high in monounsaturated fat, walnuts are high in polyunsaturated fat and animal-based fat contains saturated fat. All nuts and seeds however contain a combination of monounsaturated and polyunsaturated fat and very little saturated fat.

The results showed that ingestion of any of the three types of fat resulted in a reduction in insulin clearance, and saturated fat ingestion reduced insulin sensitivity.

Polyunsaturated fat was found to reduce glucose-stimulated insulin secretion, and in the participants that ingested the saturated fat, insulin secretion failed to compensate for the insulin resistance.

The researchers stated that failure of insulin secretion to compensate for insulin resistance as was found for saturated fat ingestion, implies impaired beta cell function.

Beta cells are cells in the pancreas that produce insulin.

Another study found that a single day of high fat, overfeeding impaired whole-body insulin sensitivity in young, healthy adults (Parry SA, et al., 2017).

References:

Parry SA, Woods RM, Hodson L, Hulston CJ. A Single Day of Excessive Dietary Fat Intake Reduces Whole-Body Insulin Sensitivity: The Metabolic Consequence of Binge Eating. Nutrients. 2017 Jul 29;9(8):818.

Xiao C, Giacca A, Carpentier A, Lewis GF. Differential effects of monounsaturated, polyunsaturated and saturated fat ingestion on glucose-stimulated insulin secretion, sensitivity and clearance in overweight and obese, non-diabetic humans. Diabetologia. 2006 Jun;49(6):1371-9.