Losing weight and getting healthier are goals that most people have had at some point in their lives. Once you’ve decided that you want to improve your health, the next step is to choose a diet to follow. A diet that has been strongly linked with weight loss and is increasingly popular, is the Keto diet. But what is it and how does it work?
Table of contents
Key takeaways
- The ketogenic diet is a low carbohydrate, moderate protein and high fat diet.
- Most carbohydrates are eliminated, and food choices focus on meats, fish, low carbohydrate vegetables and oils
- The objective is to enter a metabolic state called ketosis, where the body uses ketones, rather than glucose, as the primary energy source.
- Initial transition to a Keto diet can cause mild side effects, referred to as the Keto-flu. This normally subside within a few days to weeks.
What is the ketogenic diet?
The ketogenic diet is a very low carbohydrate, moderate protein and high fat diet.
Interestingly, the diet was initially used in 1921 by Russel wilder, as a way to manage seizures in patients with epilepsy. Since then, Keto has become hugely popular as a diet to lose weight, and is growing in popularity every year[1][2]. In fact, in 2020, the Keto diet was the most googled diet in the USA, with over 25 million unique searches[3].
The popularity of the diet is likely driven by the rising obesity epidemic.
This, combined with the successful weight loss results, has helped Keto’s meteoric rise to the top of the diet hierarchy. Keto has even influenced the rich and famous, with numerous celebrities endorsing the diet, and crediting it with their often dramatic weight loss results and body transformations[3].
What can you eat on Keto?
In practice, keto eliminates all starchy carbohydrates, and follows a macronutrient split of approximately 70% fat, 20-25% protein and 5-10% carbohydrates.
This equates to around 25 – 50g of carbohydrate per day in a 2000 kcal diet[1][2]. The Keto diet is similar to other low carbohydrate diets such as the Atkins diet, as the intention is to bring about a nutritional state called ketosis.
Any diet that significantly restricts carbohydrates and induces ketosis, can be considered a ketogenic diet[1][2].
Due to the strict restriction of carbohydrates, the Keto diet largely eliminates whole grains and refined carbohydrates.
Instead, the focus is on moderate protein and higher fats. This means protein sources such as meats, fish, eggs, and fats like oils and some dairy. In addition, lower carbohydrate vegetables such as broccoli and spinach can also be included.
Check out our sample meal plan here.
There are several common variations of the Keto diet, which have been popularised since Keto became popularised as a diet for weight loss.
Common ketogenic diet variations include:
- Classical Keto
- Focus on severely limiting carbohydrates and taking the majority of calories from fat, with a moderate amount of protein
- Atkin’s diet
- A multi-phase diet, low in carbohydrates and popularised by Dr. Robert C. Atkins
- Carnivore diet
- Eliminates carbohydrates and fruits and vegetables, and focusses on derived fats and proteins
How does the ketogenic diet work?
The Keto diet works by inducing a metabolic state called ketosis.
Normally, the cells in the body preferentially utilise sugar from carbohydrates. However, restricting carbohydrate intake results in significantly reduced insulin secretion, which leads the body to search for other forms of energy[4].
Glycogenolysis and gluconeogenesis
When the body does not have access to readily available glucose, it activates 2 processes, called glycogenolysis and gluconeogenesis.
Glycogenolysis is the process by which the body taps into stored glycogen in the muscles and liver, and converts it into energy[4].
Gluconeogenesis on the other hand, is the process of utilising non-carbohydrate substrates such as lactate, glycerol and amino acids, and converting them into glucose. When glucose levels are low, glycogenolysis and gluconeogenesis both initially each contribute approximately half of the body’s energy.
When glycogen reserves start to deplete however, gluconeogenesis takes over and is the predominant source of energy[4].
Ketogenesis leads to a state of ketosis
When this process is insufficient to supply the body’s energy requirements, the body starts to produce energy through a process called ketogenesis.
Ketogenesis is a biochemical pathway that produces ketone bodies. Ketone bodies are an alternative form of energy that can cross the blood-brain barrier, meaning it can also supply the brain’s energy needs[4].
Ketogenesis breaks down stored fat into ketones, which then circulate in the blood stream, and are consumed by cells to generate energy[5].
How long does it take to enter ketosis and what are the side effects?
The time required to enter ketosis varies between individuals, but typically ranges from 2 – 4 days, but can take up to a week.
Some recommend undergoing a fast in order to induce ketosis faster, although research has shown similar times with both Keto and fasting[6]. Ultimately, the body will begin to undergo ketogenesis after all carbohydrates have been utilised, and glycogen stores have been depleted.
During ketogenesis, the body will start to produce ketones.
Once a certain concentration of ketones circulate in the bloodstream, the body can said to be in ketosis[6].
Entering ketosis is a significant change to your body and can be associated with some short-term side effects, commonly referred to as the ‘Keto-flu.’
Common symptoms on a ketogenic diet include;
- Nausea
- Vomiting
- Headaches
- Fatigue
- Dizziness
- Insomnia
The short term (up to 2 years) side effects of Keto have been well documented, but data on longer term effects is still lacking. It is recommended to keep hydrated and supplement sodium, if necessary, to minimise side effects[4].
The ketogenic diet is here to stay
Keto rapidly gained popularity and is currently widely used, mainly for its incredibly successful weight loss stories. There have been many diets over the years but most of these are fads and are short-lived.
Keto however has stood the test of time, due to its simplicity and effectiveness. It also promotes overall health by eating ‘whole foods,’ and removes highly processed and refined carbohydrates. If you’re curious, why not check out our beginners guide and begin your own Keto journey.
