HMGCS2 and fatty liver disease: To understand whether hepatic ketogenesis insufficiency promotes diet-induced hepatic steatosis in response to fasting, 8-week-old HMGCS2 conditional knockout were treated with tamoxifen to disrupt HMGCS2 and then fed with 60% high-fat diet (HFD) for 4-weeks and then fasted for 16 hours before euthanasia.