So helping fat get into the furnace and then turning up the temperature to burn it faster would be my analogy.
The mice were given l-carnitine + NR (COMBI treatment) for 21 weeks while on a high-fat diet and the results were:
So weight gain was 17% less on the diet and fatty liver 22% less. Not bad for two non-drug supplements."COMBI treatment significantly attenuated HFD-induced body weight gain, fat mass gain (−17%) and hepatic steatosis (−22%)."
https://www.mdpi.com/1422-0067/20/18/4359/htm