That would be the C2H5OH molecule.
"The researchers identified an important, small molecule that is produced during fasting or calorie restriction conditions. The molecule, β-Hydroxybutyrate, is one type of a ketone body, or a water-soluble molecule that contains a ketone group and is produced by the liver from fatty acids during periods of low food intake, carbohydrate restrictive diets, starvation and prolonged intense exercise."
Low carb'ing I'm down 28 pounds since early April. Jeans size went from 42 to 38. Blood work showed pre-diabetes and fatty liver. My fasting blood sugar was 117, and AST reading was 49. I had just started keto, so it showed ketones at 1.0. :)
I have a keto-mojo meter and measure ketones at least once a day. Reading 1.4 at the moment.
I have stalled out at 205 lbs, so now I'm doing one meal a day, carnivore. Eating fatty tri tip, chicken thighs, 80/20 ground beef, etc. I picked up a tray of thin sliced rib steaks at Costco, they are pretty good.