Hello all,
I am embarking on a personal metabolic experiment - Many of you may be participating in #stopober (an alcohol-free October) but I’m taking it one step further… #ketober. That’s right… I’m adopting a ketogenic diet throughout the month of October. And if you’re asking yourself, “why on earth would he do that?” then read on and I will explain what ketones are, how the body makes them and what they can do for us, health-wise…
A background to ketosis
As humans, we run on 2 fuels… Carbohydrates and Fats. Protein is used for building things (think hormones, enzymes, tissues, etc…) so we tend not to burn it for energy unless absolutely necessary. Now I’m going to use an analogy to explain how we use each fuel. We can think of carbohydrates as kindling that we might use to start a fire. Kindling burns quickly and if that is all we have for fuel, we’ll need a continuous supply to keep the fire burning. Fats on the other hand can be thought of as logs. When we drop a log on the fire, it takes awhile to get going but once it’s lit it provides steady heat for a considerable time without the need to constantly top up.
When we consume carbohydrates from any source, our body breaks them down into glucose, the primary fuel our cells run on. In a similar way, fats that are digested are also broken down into fatty acids. All of our cells in the body can run on either glucose or fatty acids, except the brain. Fatty acids can not cross the blood brain barrier and therefore the brain has a major dependance on a steady supply of glucose. When levels get too low in the blood stream, it takes action and sets off a chain of hormonal events that sees the liver make new glucose. The process is called gluconeogenesis.
Regardless of how the glucose gets into the blood stream, in order to turn glucose into energy, we need to get glucose into the cells. For this we produce a hormone known as Insulin. Insulin is a storage hormone and its job is to get glucose out of the blood and into the cells. Once inside the cell, glucose is either used for immediate energy or it gets stored as glycogen (the stored form a glucose) in the liver and muscles. Glycogen is quick energy and for that reason our skeletal muscles are the largest glycogen repository in the body. When our muscles and liver can’t hold anymore glycogen, Insulin helps to push it into long-term storage (our fat cells - otherwise known as adipose tissue). So insulin is a crucial storage hormone needed to store glucose and also to store fat. In fact, we can’t store fat without insulin which is why insulin has the nickname “the fat storage hormone”.
The laws of nature mean that the quicker burning fuels will always be burned first and it’s the same in our bodies. When we have glucose in our cells we’ll use it before we make use of any fat in storage. In our ancient evolutionary past, we weren’t certain when the next meal would materialise and so fat was always protected. To use another analogy, you wouldn’t spend money from your savings account unless you had no more money in your current/checking account. This is basic survival biology and the hormone that makes it all possible is Insulin. You could say that Insulin is in charge of fuel partitioning. When glucose is onboard, insulin rises and shuts off fat burning making sure that we burn our kindling, and protect our logs.
What is ketosis?
I mentioned the brain’s dependance on a steady supply of glucose and that it can not run on fatty acids. When glucose is in short supply in the body, and we don’t replace it by consuming carbohydrates, insulin levels fall substantially. This unlocks our adipose (fat) tissue to release the stored fatty acids into the bloodstream to provide our cells with another fuel source. When fatty acid levels in the blood rise substantially the liver can’t quite metabolise all of them and a chemical called ketones is produced from the fatty acids. This is called a state of ketosis. The good news is, the brain loves ketones and once the ketone factory is rolling (and those logs are burning bright) the brain is happy and the body starts running on fat. The thing is, it doesn’t really run on both at the same time. If a significant amount of carbohydrates get introduced into the body, up goes insulin and the fat floodgates are firmly shut, taking us out of ketosis - from fat burning to sugar burning once again.
How can ketosis be achieved?
There are three ways the body can go into ketosis - starvation, fasting or carbohydrate restriction, but with the latter, there’s no need for any calorie deficit so hunger can be entirely avoided. A ketogenic diet consists of 65-75% fat, 20-25% protein and 5-10% carbohydrates (mostly in the form of non-root vegetables because grains, legumes and root veg contain a lot of glucose and will kick the body out of ketosis “faster than a speeding bullet” ;-).
The benefits of ketosis
A major side-effect of going into ketosis is a rapid loss of body fat, especially around the trunk. Like many of us, I’ve put on an inch or two around the mid-section from the whole lockdown experience that I’d like to burn off, but apart from that, I’m also keen to experience the many other reported health benefits that occur when we shift into ketosis, including; higher energy levels, a heightened insulin sensitivity, better blood sugar management, an improved cholesterol profile, a reduction in inflammation and oxidative stress and better cognitive function. But above all, I want to become more “metabolically flexible”. What do I mean by that..? Most of us on the planet are hardened sugar burners from decades of following government guidance (“6-11 servings of starchy carbohydrates per day”). The longer we run our engines on carbs, the harder it becomes to switch fuel tanks and we spend much of our life on the blood sugar rollercoaster, fuelling sugar cravings with more and more carbs despite having plenty of energy stored as fat that our body has forgotten how to tap. By periodically going into ketosis we retrain our bodies to be more metabolically flexible, able to run on carbs when they’re present and easily switching to our fat reserves when not.
So hopefully that explanation makes sense and you now have a better understanding of what ketones are, how we make them and what are the health benefits. If anyone wants to come along for the ketone ride in October, I’d welcome the company. Wish me luck! :-)
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