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What is the ketogenic diet?

The ketogenic diet is a low-carbohydrate, moderate-protein, and high-fat diet that shifts your body’s energy source from glucose to fat. This results in the production of ketones, which many cells use for energy. It is often referred to as a “fat-burning” diet due to its focus on burning fat for fuel.

Reducing carbohydrates is the key component to achieving a state of ketosis. Individual carbohydrate tolerance varies, but most people need to limit carbohydrate intake to below 50 grams per day. Those with diabetes or insulin resistance may need to stay below 25 grams per day.

How does a ketogenic diet work?

By significantly reducing carbohydrate intake, the body enters a state of ketosis where it relies on fat and ketones for energy instead of glucose. This shift in metabolism offers various health benefits, including improved blood sugar control, reduced insulin levels, and enhanced appetite control.

Where does blood sugar come from on a ketogenic diet?

On a standard western diet, blood glucose primarily comes from carbohydrates. On a ketogenic diet, the body generates glucose from fat and protein through gluconeogenesis, a natural process that helps maintain stable blood sugar levels.

Are carbohydrates an essential nutrient?

No. There is no such thing as an essential carbohydrate.

Our bodies do require a certain amount of glucose to function. On a ketogenic diet, the body generates its own glucose from fat and protein through a process called gluconeogenesis.

When the metabolism is adapted to run on fat, all of the body’s requirement for glucose will be adequately satisfied via this demand driven process of gluconeogenesis. The precise amount of glucose your body requires will be generated by your liver and does not need to come from an external source.

Contrary to popular belief carbohydrates are not an essential nutrient and our bodies do not require a single gram of carbohydrate to be consumed.  Your body can use ingested carbohydrates but this is not a requirement.  Stated another way, you cannot die from a lack of consumed carbohydrates.

What are the health benefits of a ketogenic diet?

Extensive scientific research [Ref 1] supports the effectiveness of the ketogenic diet in managing conditions such as obesity, type 2 diabetes, epilepsy, heart disease, cancer, Alzheimer’s disease, and more. Emerging evidence suggests its potential benefits in various medical conditions such as auto immune diseases.

A ketogenic approach has been shown to be particularly successful in achieving drug free Type 2 Diabetes Remission.

“Advice and ongoing guidance on a low-carbohydrate diet in primary care can achieve improved diabetic control for 97% of those interested in the approach, sustained for an average of 33 months”

Dr David Unwin, BMJ 2022

Source: Unwin D, Delon C, Unwin J, et alWhat predicts drug-free type 2 diabetes remission? Insights from an 8-year general practice service evaluation of a lower carbohydrate diet with weight lossBMJ Nutrition, Prevention & Health 2023;6:doi: 10.1136/bmjnph-2022-000544

What are ketones?

Ketones are molecules produced when the body burns fat for energy. The primary ketone, beta-hydroxybutyrate, is the most efficient fuel source for cells and can be measured using blood ketone strips. Ketones play a crucial role in maintaining the body’s energy balance during ketosis.

What are the macronutrient recommendations for ketosis?

Ideal carbohydrate and protein intake varies based on factors like age, gender, activity level, and health goals. Generally, carbohydrate intake should be very low, and protein intake should be moderate, with the rest of the calories coming from healthy fats.

How much carbohydrate can you have on a ketogenic diet?

Individual carbohydrate tolerance varies, but most people need to limit carbohydrate intake to below 50 grams per day. Those with diabetes or insulin resistance may need to stay below 25 grams per day.

How much fat and protein can you have on a ketogenic diet?

Once carbohydrate is kept below 50 grams per day, the majority of individuals find that they can eat fat and protein to satiety. The restriction in carbohydrates allows a fat adapted individual to rely on their own body’s satiety signals to inform when and how much to eat. The simplicity of the ketogenic diet and being fat adapted is to simply ‘eat when hungry and stop when you are full’.

How do I prepare to start a ketogenic diet?

Before starting a ketogenic diet, consult with a healthcare provider, especially if you have pre-existing health conditions. Blood tests, investing in blood ketone and glucose meters, planning meals, and stocking your kitchen with keto-friendly foods are important steps to take.

A great basic start is to cut back on all forms of sugar, including all complex carbohydrates such as bread, pasta, rice and starchy vegetables.

Eliminate all ‘vegetable oils’ and instead replace with high quality fats such as butter, lard, olive oil, coconut oil and ghee.

Focus on increasing your protein and associated fat intake. Fatty meats are a fantastic source of both.

What is the difference between ketosis and being fat adapted?

It is important to note that being in ketosis and being fat adapted are not the same thing.

Ketosis is the initial phase where your body shifts from using carbohydrates to burning fat for energy, resulting in the production of ketones. During this transition, your body may still preferentially burn carbs, making it susceptible to getting knocked out of ketosis by sudden carb intake.

In contrast, being fat adapted signifies a more prolonged metabolic transition. It indicates that your body has become efficient at using fat as its primary energy source, leading to stable energy levels.

While ketosis can be achieved in a matter of days, fat adaptation typically takes several weeks and involves a shift towards sustained fat metabolism.

How do you know if you are in ketosis?

The body is in a state of ketosis when the liver is producing energy in the form of ketone bodies via the conversion of fatty acids [Ref 2] .

These ketone bodies can be tested in three main ways: blood, breath, and urine tests. Each method measures different ketone molecules, with blood tests assessing β-hydroxybutyrate, breath tests measuring acetone, and urine tests gauging acetoacetate levels.

How do you know if your body is fat adapted?

The natural signs of being fat adapted encompass several benefits. These indicators include reduced cravings between meals, sustained energy levels, feeling satiated with smaller food portions, heightened mental focus, consistent fat loss, improved sleep quality, and enhanced physical endurance. These signs reflect your body’s successful shift towards utilising fat as its primary source of energy, resulting in improved overall well-being and performance.

If the body has so much stored energy, why don’t we all use it?

The regular consumption of carbohydrates results in elevated levels of a hormone insulin. Insulin essentially ‘locks the door’ to access the body’s vast fat reserves and the body then must rely on the much smaller 2000 calorie glycogen fuel tank. It explains why endurance athletes ‘hit the wall’ during an event as they have exhausted their carbohydrate dependent metabolism. In order to compensate, athletes must ‘refuel’ with carbohydrates despite having an enormous store of energy in the form of fat due to it being inaccessible [Ref 3] .

Read more here

How does eating carbohydrates prevent fat burning?

When carbohydrates (carbs) are eaten, blood sugar in the body increases and our pancreas produces a hormone called insulin to bring it back down. In addition to controlling blood sugar, insulin is a fat accumulation hormone that stimulates the storage of fat and prevents it’s breakdown.

When insulin levels are high due to carbohydrate consumption, the body doesn’t burn its own fat for energy and instead stores incoming food as fat. By reducing carb intake, via a ketogenic diet, insulin levels decrease, allowing the body to use fat for energy and aiding fat burning.

Essentially, controlling carbs helps the body switch to using fat for fuel.

How can I track my progress on a ketogenic diet?

Blood ketone and Continuous Glucose Meters (CGM’s) are excellent tools to monitor your ketone levels and blood sugar will provide excellent feedback to determine if your body is in a ketogenic state. Once a person is fat adapted there are some natural signals such as increased satiety, a more stable mood and increased energy.

A ketogenic diet is often used a tool for individuals wanting to lose fat. If weight loss is your goal, the scale is not the best tool for measuring success. A much better method would be to measure waist circumference as it will start to improve well before the scales may indicate an improvement.

Is fiber necessary on a ketogenic diet?

Absolutely not. It is a common belief that fiber is an essential part of a healthy diet and is particulary necessary to prevent constipation. A lack of fiber does NOT cause constipation and can actually be it’s CAUSE. This paper published in the World Journal of Gastroenterology in 2012 concluded:

“This study has confirmed that the previous strongly-held belief that the application of dietary fiber to help constipation is but a myth. Our study shows a very strong correlation between improving constipation and its associated symptoms after stopping dietary fiber intake”

In fact, it showed that a zero fiber diet resulted in 100% effectiveness for completely resolving ALL constipation and associated symptoms.

See below for a great talk by Dr Paul Mason in which he addresses the myths about fiber: