Acute Dietary Fat Intake Initiates Alterations In Energy Metabolism And Insulin Resistance, Journal of Clinical Investigation, 23 January 2017
This study demonstrates that a single oral dose of saturated fat increases hepatic TG [triglyceride] accumulation, insulin resistance, GNG [gluconeogenesis], and ATP concentrations in the human liver. Ingestion of saturated fat also induces peripheral insulin resistance in skeletal muscle and adipose tissue.
One fatty meal. One. Note that the people who received the fat meal, which did not include any carbohydrate, experienced a rise in blood glucose and blood insulin. That’s because the liver started pumping out glucose (that it was making from gluconeogenesis, which uses bits of the body’s protein, which it steals from things like muscle).
This was a German study.