On ketogenesis and exogenous ketones
Updated: Nov 2, 2022
Let’s break this down. Ketone bodies are three water-soluble molecules:
and their spontaneous breakdown product, acetone – (measured in breath))
They are produced by the liver from fatty acids during periods of low food intake (fasting), carbohydrate restrictive diets, starvation, prolonged intense exercise.
The overall aim of ketogenesis is to make Acetyl-CoA. This can be used by make ATP. ATP is the energy currency of the human body. It all boils down to Gibbs law of free Energy. ATP demand governs all.
What does this mean?
The body will only burn fuel to make enough ATP to sustain energy NEEDS. No more. So, when people add Ketone bodies to the diet, all you are doing is adding a fuel to make ATP. There is a hierarchy of fuel use by the body; Glucose, Ketone bodies, Proteins and Fats. So, adding ketones only add more fuel (like food) to the mix. Your need for fat is diminished. Just by adding Ketones, does NOT make you lose weight.
Energy balance is simple:
Body Weight = Food Intake (including ketones) + Energy Expenditure.
You lose weight because you eat fewer calories or burn more from energy expenditure. Not because you are taking ketones – this is simply not true in energy balance.
The only way you can circumvent this system to burn more fat than needed is by uncouplers. I.e. UCP1, Dinitrophenol, Brown fat – like hibernating BEARS.
Exogenous Ketones will not increase fat burning beyond what is needed to maintain ATP or body weight. You lose weight because you are in an energy deficit.
Will you eat less?
Do exogenous ketones make you EAT less... No!!! Ketone bodies are a starvation signal. So, it often causes a natural response to eat more.
See article by the American Journal of Physiology, Endocrinology and Metabolism: https://www.ncbi.nlm.nih.gov/pubmed/26530151
People who are in ketogenic states, or take ketone bodies, are less likely to eat refined carbs – this will help in eating less, insulin response and lipolysis/fat burning. So, there is probably somewhat of a placebo effect. I have not even touched on the insulin, glucagon, catecholamines regulation of energy balance, ketone production in the liver or lipolysis. Basically, if you take ketone bodies as a supplement, and still consume carbs from any source you are going to blunt the real ketogenesis process
Oh yeah, measuring acetone in your breath (after taking ketone bodies as a supplement) does not mean you are in true ketogenesis. It just means you are breaking down an additional fuel source from acetoacetate and beta-hydroxybutyrate to make... get ready for it... ATP.