The ketogenic diet has become trendy in recent years, advocating a high fat, low carbohydrate, moderate protein approach. Many have reported effortless weight loss on the diet as well as improved cognitive function and enhanced physical performance, particularly in endurance events since the diet forces the body to learn to utilise fat efficiently as a fuel source rather than to rely solely on the limited amount of carbohydrate we can store in the body. So what exactly is the ketogenic diet and why do people follow it?

What Is The Ketogenic Diet?

Origins Of The Ketogenic Diet

The ketogenic diet first gained popularity in the 1920s and 1930s when doctors started using it to control seizures amongst patients with epilepsy. Originally, the diet was created by manipulating the macronutrients one consumed so that they would consume a diet high in fat and low in carbohydrates so that the body would be forced to use fat for energy.

This state within the body where the energy is generated almost solely from fat is known as ketosis. It produces ketones from fats which the body and brain can use as an alternative fuel source in addition to glucose.

Macronutrients In A Ketogenic Diet

One of the first calculations used to standardise the diet was:

  • 1g protein per kg bodyweight
  • 10g – 15g carbohydrates per day
  • Rest of your energy from fats

Nowadays these macronutrients have been adapted slightly, although the diet remains more or less the same with a minimum of 70% of one’s calories coming from fats. Some opt for higher protein intakes and many allow for 20g – 30g carbohydrates per day, with some allowing as many as 50g whilst discounting carbohydrates from leafy green vegetables. There are many variations, but ultimately the point of the ketogenic diet is to teach your body to utilise fat as the main substrate for energy.

I feel that many people can reach ketosis on less than 50g carbohydrates per day. I think that if you’re prone to seizures, you’re probably better off with fewer carbohydrates since this can help to prevent and reduce seizures. Because of this, based on the research and experimentation I’ve done I’d suggest trying the following adapted macronutrient profile:

  • 2g protein per kg bodyweight (I think this is an optimal amount)
  • Up to 50g carbohydrates per day
  • At least 70% of your energy from fat

If you’re an athlete and you trained hard on a training day you may even be able to get away with 70g carbohydrates if you time them so the majority are consumed after your workout. As a point of interest, it may even be possible to consume higher amounts of carbohydrates if you eat carbohydrates with a low food insulin index as one of the main benefits of the ketogenic diet and ketosis is keeping insulin levels relatively low and stable. Bear in mind a few of your carbohydrates will come from fat and protein dominant foods.

Starting A Ketogenic Diet

If you’ve decided you want to start a ketogenic diet, it’s unlikely you’ll find it easy initially and I don’t recommend jumping straight into it. I’d suggest starting with the following dietary changes and becoming comfortable with them before starting:

  • Eliminate all refined and ultra-processed foods.
  • Stop consuming sweets and foods high in sugar.
  • Remove sugary juices and sodas from your diet.
  • Try to reduce carbohydrate intake to 100g – 150g carbohydrates per day.

Once you’ve managed these steps, I think you’re good to go if you’re going to start a ketogenic diet. This will help to set you up for success by eliminating some of the main problems people have when sticking to a ketogenic diet although some people have a difficult transition period in which they catch ‘keto flu’.

Why Follow A Ketogenic Diet?

People tend to follow a ketogenic diet for a variety of health reasons such as:

  • Reduced blood glucose
  • Reduced insulin spikes and fasting insulin
  • Fewer hunger pangs throughout the day
  • Increased energy throughout the day
  • Enhanced ability to utilise fat as a fuel source

Many of the benefits of following a ketogenic diet come from the switch of fuel sources as the body is forced to burn fat for fuel rather than glucose. Lots of people consume far too many carbohydrates for their everyday activity which is why we are seeing more and more people becoming diabetic and prediabetic.

Ketogenic Diet And Keto Flu

Keto flu is a series of symptoms experienced by people starting a ketogenic diet and is usually caused by the body being forced to fuelling itself on a low amount of carbohydrates. A drastic reduction in carbohydrates can shock the body resulting in withdrawal-like symptoms which is why I recommend reduces daily carbohydrate intake before starting a ketogenic diet.

Some people will have no symptoms whatsoever whilst for others the severity of symptoms will range from mild to severe.

Symptoms include:

  • Stomach pain
  • Dizziness
  • Brain fog
  • Nausea
  • Vomiting
  • Constipation
  • Irritability
  • Muscle weakness
  • Muscle cramps
  • Diarrhoea
  • Sugar cravings
  • Low energy levels
  • Struggling with concentrating
  • Difficulty sleeping
  • Headaches

It doesn’t sound too good which is why it’s better to reduce carbohydrate intake slowly over weeks or months before following a ketogenic diet.

Other Causes Of Keto Flu

As well as a drastic reduction in carbohydrate intake, there are a few other possible causes of experiencing keto flu:

  • Electrolyte loss and dehydration
  • Lack of micronutrients

Electrolyte Loss And Dehydration

With a rapid reduction in carbohydrates, it is likely you will lose a lot of water from your body. This is because glycogen in your body is bound to water (1 of glycogen binds to 2g – 3g of water) so with a reduction in carbohydrates, a lot of the weight lost initially will be water weight. But you’re not just losing water when you urinate, you’re losing the salts and electrolytes too which can cause electrolyte imbalances.

To combat this you’ll want to make sure you’re drinking enough water and consuming electrolytes like potassium, magnesium and sodium. I’d even recommend adding sea salt to your water to help obtain these electrolytes to help reduce symptoms of keto flu.

Lack Of Micronutrients

When starting a ketogenic diet some people aren’t sure what to eat and end up eating a limited range of foods which can result in a lack of micronutrients. This can cause nutrient deficiencies which may contribute to some of the symptoms of keto flu which are being experienced.

To ensure you get a range of micronutrients I suggest consuming and rotating the following foods on a daily or weekly basis:

  • Fatty cuts of meat (grass-fed ideally)
  • Eggs (organic free-range ideally)
  • Cacao powder
  • Nuts and seeds
  • Leafy green vegetables
  • Cruciferous vegetables
  • Berries in small amounts (raspberries, blackberries and blueberries – they’re low in sugar)
  • Red meat
  • Poultry
  • Seafood (fish, mussels, prawns)

If you can’t stand eating any of these in particular, you can always supplement to try and hit your nutritional requirements and get a large dose of micronutrients to help combat keto flu.


That’s all from me today on the breakdown of the ketogenic diet. Stay tuned for some related follow-up posts! If you found this post informative, why not share it with others who’ve heard of or are considering the ketogenic diet?