Pages Menu
Categories Menu

Posted by on Apr 29, 2014 in Fitness Tips | 0 comments

What is Ketosis? Part One

Hans-Krebs

Most people I speak to are unaware of ketosis and its benefits, but it’s a topic I’ve been following for a while.

This post will be somewhat scientific, but I hope that doesn’t turn some of you off. I aim to help anybody reading this to understand what ketosis is and why it’s important.

Usually I write about workouts but I aim to provide more nutrition based content (e.g. my detox diet post), and this will be a two-part article.

Ketosis Defined

Ketosis is a metabolic state where the liver produces molecules known as ‘ketone bodies’ at certain levels. I’m not advising that everyone will desire to be in ketosis, as you’ll soon see. Each person is different and should adjust their goals accordingly.

The 3 ketone bodies in question are acetone, acetoacetic acid, and beta-hydroxybutyric acid.

Now, our bodies require energy to function. You may recall from biology class that ATP is the energy currency of our cells. If we cannot produce sufficient ATP to supply our cells, it is fatal in a very short time. Glucose is a particularly important molecule that provides energy, particularly to the brain (which typically expends about 20% of our overall body energy).

Some glucose can be stored in the liver. Some is stored in muscles too, but only in a form that prevents it from being released back into the bloodstream (it therefore cannot be donated to the brain for instance – it can only be used by your muscles). If you run out of glucose, you depend on your liver to release glycogen.

The Krebs Cycle

KrebsYou may also recall the Krebs Cycle from school. This is how energy is derived from molecules like glucose or from fats. The main thing you need to remember is that in the electron transport chain, you trade the stored energy of electrons dropping down to lower energy states for the stored form of energy in the phosphate bonds (ATP).

So finally, our ketone bodies come into the equation. In the Krebs Cycle, acetyl CoA comes from fat and can be converted into energy. Our bodies much prefer to use fats to feed into the Krebs Cycle, because it would be a huge waste to use too much protein.

In the absence of acetyl CoA, our livers have evolved to convert fats into ketones like beta-hydroxybutyric acid. It is precisely because of this that we are able to survive for weeks without food. Our bodies can convert these ketones into substrates that feed into the Krebs Cycle, and in turn that produces more ATP.

If we had to rely solely on glucose, we would be dead within a few days!

This is why I find this a fascinating subject, and many people are unaware of it. I have to thank Peter Attia for introducing this topic to me, and I’m still learning about it. If you want to get a deeper understanding, Ketosis 101 on Peter’s blog is a great starting point.

Ketosis is a metabolic state – typically your body won’t be in it unless you are purposefully trying to achieve it through your diet.

This leads onto questions about whether it is desirable for your body to be in ketosis – what are the benefits and drawbacks?

I will aim to cover questions like this in part 2 of this article next week. Stay tuned until then and please leave a comment if you found this interesting or are familiar with ketosis at all.

Post a Reply

Your email address will not be published. Required fields are marked *