Ketosis, keto diet, fat adapted

As the Tour de France comes to an end for this year, I was reminded of the Chris Froome diet story from a couple of years ago. He is a four times TdF winner who attributes his winning performances to adopting a low carbohydrate, sometimes call keto, diet*. So what is a keto diet? What are the benefits?

This blog will explain ketosis, the keto diet and being fat adapted. All terms you may have heard of that get thrown around, cause a lot of confusion and are topics I regularly get asked about by my coaching clients. What do they all mean? And is it really true we need carbohydrate for energy? And is the fast ‘fact’ below from a recent cycling magazine article true, saying your body will break down your muscle if you don’t eat enough carbs?!?

We are hybrids!

The human body is a very sophisticated system and has two different energy sources or fuel types – glucose and fat. Glucose is a sugar and carbohydrates are essentially glucose molecules joined together that the body quickly breaks apart. When we use fat for fuel we break it down into ketones – hence the use of the term keto diet, for a low carb, higher fat, diet. And when we are primarily using fat for our energy we are in ketosis. We truly are hybrid models running a seamless dual fuel system! 

Most cells in our body can use both types of fuel but some, such as the all important brain cells, are heavily reliant on glucose. But the key thing to know is that we don’t actually need to eat glucose (or sugar or carbohydrates) to get what we need for our brains – we can make it in the body from fat. Carbohydrate is biologically speaking an non-essential macro nutrient and we can survive, and thrive, on protein and fat based foods. We do generally like to eat sugary and carbohydrate based foods as they are a quick and easy energy source for the body, but they aren’t necessary for us.

We can think of glucose as being like the food in our fridge, which has limited storage. It is easy to access and typically the first place we look when we are hungry and need something to eat. Our fat stores are more like our freezers – harder to access but with more space and storage capacity. We can even put in additional freezers in the garage when we run out of space. Excellent food storage for a famine. Except we don’t have much famine in our modern society!  

Insulin is the fat storing hormone produced in response to the sugar/carbs we eat that raise our blood sugar levels. Too much glucose in our blood is toxic if it goes beyond a tightly controlled level and so one of the top priorities of our bodies is to get high levels back down to prevent damage. Insulin helps our cells use the glucose for fuel and turns blood sugar into glycogen for easy access glucose storage in the liver and muscles. We have limited capacity for glycogen storage so once these stores (or fridge) are full insulin stashes the rest of the blood sugar away as body fat to use later when we are not eating and the glucose has gone.  

We have a vast capacity to store fat 😟 and will increase our body fat levels if we have too much sugar/carbs coming in through our diet. The other important point is that when we have insulin out and about in our system we are unable to use our body fat for fuel, so it stays put, and we continue to rely on glucose for our energy needs.  

Over time too much sugar/carbs coming in from our diet leads to more and more insulin being produced and we can become insulin resistant, or carbohydrate intolerant, meaning we become less good at dealing with the incoming glucose. More body fat builds up leading to weight gain and we can become less good at controlling our blood sugar leading to prediabetes/diabetes. In this state our body essentially struggles to ‘see’ the body fat we have and continues to keep feeling hungry for more sweet/carby food. The fat stores continue to build up. And up… 

If we are overweight, particularly around our waists, we are likely to have too much insulin caused by eating too much sugar/carbohydrate for our body. To lose weight we must control insulin and have times when insulin levels are very low so we can use our body fat for fuel. Being overweight is essentially a problem of too much insulin and we can tackle this through dietary change, particularly reducing our sugar/carbohydrate intake. 

Jason Fung explains this very well in his book The Obesity Code and in various YouTube films. Try this one: https://youtu.be/3d7KkyXnyB4

Another good book is The Case For Keto by Gary Taubes. Very readable, very practical and it explains how we got into our current dietary guidelines mess.

Changing what and how we eat is one of the most important things we can do to reduce insulin levels and insulin resistance to get that excess body fat out of the deep freeze and providing the energy we need. 

What is ketosis?

Ketosis is a metabolic state when our body is burning fat for energy instead of glucose. When we are in this state we are turning our body fat into ketones helping reduce excess body fat and taking us off the glucose roller coaster where we eat and feel hungry again a few hours later. Being in ketosis generally means we are able to go for longer without eating as our body is happily getting the energy it needs from fat rather than relying on the quick fix glucose. 

It can take a few weeks for our bodies to fully adjust to using fat for fuel when we reduce our sugar/carbohydrate intake rather than relying on the glucose drip feed and when we achieve this state, we are what is known as ‘fat adapted’. A state where we are able to use our body fat for fuel, go for longer without feeling the desperate urge to eat and can start to break down our excess fat stores leading to weight reduction.  

And to answer the question posed at the beginning of this article, no restricting carbs does not mean your body will start breaking down muscle for fuel. The opposite is actually true - being fat adapted preserves lean muscle tissue.

The low carb eating spectrum and keto diet

There are no hard and fast rules over what is a keto diet compared to a low carb diet, but many consider staying below 50g carbohydrate a day to be a strict low carb or keto diet. This is what I try and do as a diabetic in long term remission.  

The typical diet in this country and suggested by our flawed dietary guidelines are to eat at least 260g of carbohydrate a day – think bowls of pasta with a little sauce, sandwiches and crisps for lunch and a breakfast of cereal, toast and juice. Cutting out snacks, anything sugary, ultra-processed foods and sticking to three wholesome meals a day could be called a ‘real food’ diet, as advocated by the PHC phcuk.org (Public Health Collaboration).  

Making a more conscious effort to cut down the purer refined carbs (bread, rice, pasta, potatoes) would typically be described as a lower carb diet – either liberal or moderate depending how low you go – but not a full on keto diet. See below for an overview of the low carb spectrum and I can provide more details on what this looks like in terms of meals/foods if you are interested. Just drop me a message 👍 

How much carbohydrate should I be eating?

We are all individuals, with our own unique biology and metabolism, and so the right level of carbohydrates for our own body will vary for each of us. An answer many people don’t like as they just want to be told what to eat and then get on with it!  

If you are overweight, have a thick waist or feel hungry again a couple of hours after eating then you should think about reducing your carb intake, to help switch your body to using your body fat for fuel more often. You should be able to go longer without eating and avoid relying on grit and willpower to overcome the urge to snack or binge.

In my coaching work I help clients figure out what is a good level of carbohydrate for them and help them makes changes to their diet to improve their health and lose weight. Focusing on changes they can stick with that fit around their families and individual lifestyles. If you would like a discussion about your carbohydrate intake and dietary needs do drop me a message as I am able to offer a free 30 minute introductory session. You can also book directly by following this link and choosing your time slot: watch-your-waist/discovery-meeting

Contact me to arrange a chat if you struggle to sustain weight loss or are worried about diabetes or prediabetes to discuss how I could help you make sustainable changes to your diet that fit with your lifestyle, helping you improve your long term health. I can help you find your waist again.

* More about Chris Froome and his low carb diet can be found here: https://www.diabetes.co.uk/blog/2016/07/low-carb-diet-propelled-chris-froome-three-tour-de-france-titles/