Do ketones from H.V.M.N. Ketone Ester get turned back into fat?
The short answer is no. There is not a metabolic pathway whereby ketones are easily turned back into fat. Read on for more technical detail below.
Metabolism is highly complex and there are many factors that affect fuel use. There are also big differences between all of the tissues in the body (fat vs. liver vs. muscle vs. brain vs. heart).
Important factors in fuel use include 1) uptake into tissues, 2) enzyme activity, and 3) end product inhibition (i.e The Randle Cycle).
Just because there is an enzyme pathway that could conceivably make a conversion does not mean it is operational in human metabolism.
There is not a metabolic pathway whereby ketones are easily turned back into fat, because this would be a "futile" metabolic cycle: turning fat into ketones and then back into fat.
The process of making new fat is called de novo lipogenesis (DNL). It requires elevated levels of a molecule called acetyl CoA (ACoA). ACoA gets turned into fat. This mainly happens in the liver and the fat tissue. Evidence for DNL happening elsewhere in the body is limited.
The liver cannot convert ketones into ACoA, as it doesn’t have the necessary enzymes. Therefore BHB is highly unlikely to contribute to DNL in the liver.
Only a small amount of fat stores in fat tissue comes from DNL (~10%), and only when the body is in energy excess. Therefore, conversion of ketones back into fat would likely be minor, if it occurred at all.