Continue reading to learn about the science behind the ketogenic diet, who should follow it, and some rules of engagement for success on the ketogenic diet.

What is the ketogenic diet?

The ketogenic diet is a high-fat, very low carbohydrate diet. The keto diet plan is simple: its purpose is to shift your body to a fat-burning metabolic state, known as ketosis. The metabolic state in which the body relies on ketone bodies for energy as a result of glucose depletion is known as “nutritional ketosis”.

It’s important to note that “nutritional ketosis” is not the same as ketoacidosis. Ketoacidosis is a serious complication of diabetes in which individuals have high blood glucose and ketone levels as a result of inadequate insulin. In comparison, “nutritional ketosis”, induced by severely restricting carbohydrate intake, does not cause high blood glucose levels or changes in blood pH. (7)

avocado. salmon, nuts, red meat, cheese, eggs, and oil all in raw form on table

The keto diet is a high-fat, very low carbohydrate diet.

How does the ketogenic diet work?

Under normal conditions, glucose from carbohydrates is the primary source of fuel for the body. However, when carbohydrates are severely restricted from the diet and glucose stores are depleted, the body will metabolize and utilize fats as an alternative source of fuel. (4)(12)

When dietary intake of carbohydrates is limited, the body will first use available glycogen stores. (2) Glycogen is the storage form of glucose found primarily in the liver and the skeletal muscle. The body is able to store approximately 600 g of glycogen, however this number may vary based on individual differences including diet, body mass and activity level. (9)

Once glycogen stores have been depleted, the body will undergo gluconeogenesis in which glucose is produced endogenously from substrates such as lactic acid, glycerol, and certain amino acids. Finally, when endogenous glucose production is insufficient, the body will shift into ketosis and fat will replace carbohydrate as the primary macronutrient used in energy production. This shift will occur after only a few days of consuming a reduced carbohydrate diet of up to 20-50 grams per day in a 2,000 calorie per day diet. (7)(12)

During the biochemical process of ketogenesis, the body metabolizes fats into fatty acids, which are then metabolized to ketone bodies. The most common ketone bodies, beta-hydroxybutyrate and acetone, are formed through the conversion of acetoacetate. This process occurs primarily in the liver. (7) A series of reactions convert ketone bodies to acetyl-CoA, allowing them to enter the Krebs cycle and be converted to the high-energy molecule adenosine triphosphate (ATP). (12) ATP— known as the “universal energy currency”— provides energy to the body and drives biological processes. (5)

Learn more about energy systems on the Fullscript blog.

What are the signs of ketosis?

How do you know if your body is burning fat instead of carbohydrates? As the benefits of the ketogenic diet depend on the body being in a state of ketosis, this is an important question to ask. Ketone bodies are eliminated through the urine, therefore, high levels of ketones measured in urine are one indication that the body is in a state of ketosis. Health practitioners monitoring your diet may regularly collect and test urine samples to measure ketone levels. Another indication of ketosis is “fruity breath” that occurs as a result of acetone, a byproduct of ketone acetoacetate decarboxylation, eliminated through respiration. (12)

Did you know?
Although rare, acetone can sometimes be converted to isopropanol, which can trigger a positive result during an alcohol breath test. (7)

Who should follow a ketogenic diet?

Every individual is unique and, like all therapeutic diets, the ketogenic diet may not be for everyone. Research has demonstrated the benefits of the ketogenic diet for a number of health conditions, particularly in addressing pediatric epilepsy and metabolic conditions such as obesity.


The ketogenic diet has recently gained popularity due to its ability to promote weight loss. Research has demonstrated that the diet is an effective weight loss strategy. It has also been successful in improving biomarkers of metabolic syndromeinsulin resistance and type 2 diabetes in overweight individuals. Results of studies have shown improvements in blood glucose regulation, insulin sensitivity, triglyceride levels and HDL cholesterol levels. (7) In addition, the ketogenic diet may improve other factors related to weight gain and obesity, including improvements in mood, cognitive impairment, and longevity. (12)

A review discussing the use of the ketogenic diet in the treatment of obesity found that obese individuals following a very low carbohydrate diet demonstrated improved glycemic control, haemoglobin A1c levels, and lipid markers. Individuals with insulin resistance also demonstrated improved markers of metabolic syndrome. Although an exact mechanism has yet to be determined, the authors proposed several possible explanations for these benefits including: reduction in appetite and improved appetite control; greater metabolic efficiency as a result of fat consumption; increased lipolysis and reduced lipogenesis, and increased energy requirements of gluconeogenesis. (12)

Another study examined the effects of a long-term ketogenic diet in obese individuals. For 24 weeks, subjects followed a diet consisting of 30 g of carbohydrate, 1 g/kg body weight of protein, 20% saturated fat, and 80% polyunsaturated and monounsaturated fat. Results showed increases in HDL and reductions in body weight, BMI, triglycerides, LDL cholesterol, and blood glucose. The results of this study also demonstrate that the ketogenic diet may be safe to follow for longer periods of time without significant side effects. (3)

Paediatric epilepsy

Despite its recent popularity as a weight loss intervention, the ketogenic diet was originally developed in the 1920s to address epilepsy in children. When following a ketogenic diet, the body undergoes ketogenesis as a result of severe carbohydrate restriction in the diet, mimicking the effects of fasting. At the time, it was observed that fasting had protective, anti-seizure effects, which led to the use of the ketogenic diet. (1)

Since then, research has demonstrated the beneficial effects of the diet in children with epilepsy. A systematic review examining the effects of the ketogenic diet in children with refractory epilepsy concluded that the diet significantly reduced the frequency of seizures. (6)

Similarly, a randomized controlled trial examined the effects of the diet in 145 children with treatment-intractable epilepsy experiencing more than seven seizures per week. Seizure frequency measured after three months was significantly lower in the ketogenic diet group compared to the control group, supporting the use of the ketogenic diet as an effective lifestyle intervention. (10)

Other health conditions

While obesity and epilepsy are the most well-known and researched uses of the ketogenic diet, we are now seeing promising research results for a number of other health conditions. In a review of literature, authors identify several conditions for which the ketogenic diet may be beneficial including brain trauma and ischemia, cancer, Parkinson’s disease, Alzheimer’s disease, ALS, autism, depression, migraines and narcolepsy. (1)

Tips for a successful ketogenic diet

The key to following any successful diet is to adhere to a few evidence-based rules of engagement (and a little bit of planning, of course!).

Rule 1: Know your macronutrient breakdown

When it comes to the ketogenic diet, following a strict macronutrient breakdown is essential. Consuming the right proportions of fat, protein, and carbohydrates will ensure your body remains in a state of ketosis. For example, if you’re not consuming enough fat, or you’re consuming too much carbohydrate, your body will always prioritize glucose as a primary source of fuel. Similarly, too much protein will be converted to glucose and inhibit ketosis.

The approximate macronutrient breakdown for a ketogenic diet is as follows:

  • 70-75% from anti-inflammatory fat
  • 20-25% from good quality protein
  • 5-10% from low-glycemic, nutrient-dense carbohydrates (8)

Rule 2: Try to stay plant-based

One common misconception about the ketogenic diet is that it’s necessary for you to consume animal products in order to adhere to the diet. Actually, with proper planning and education, it’s possible to follow a vegetarian ketogenic diet. While you don’t need to strictly cut out all animal products, it’s best to incorporate anti-inflammatory, plant-based foods such as nuts, seeds, coconut, and avocado in your keto diet food list.

Rule 3: Quality is key, especially with animal products

Although it’s not necessary to consume animal products on a ketogenic diet, when choosing meat and other animal-derived products, quality is key. Look for products with labels such as organic, free-range, pasture-raised, wild-caught or sustainable.

woman holding red chilly peppers in local food market

Buy organic produce to prevent unnecessary toxins entering your body.

Rule 4: Buy organic produce

Ultimately, the goal of a therapeutic diet is to heal your body. Exposure to pesticides and herbicides contributes to your body’s toxic load as they are fat-soluble and can be stored in your organs and tissues. (13) Choosing organic can reduce your exposure to these potentially harmful chemicals.

Rule 5: Avoid refined products

In order to help your body heal, it’s also important to avoid refined foods. Refined foods, such as deli meats and poor quality dairy may have added preservatives and nitrates. They can also promote inflammation in your body, which may contribute to weight gain and numerous other chronic health conditions. (11)

Rule 6: Choose better sugars

When restricting carbohydrate intake and sticking to nutrient-dense, low-glycemic options, cutting out the sugar “cold turkey” can be difficult, especially if you have been typically following a standard North American diet. Incorporating natural sugar alternatives, such as stevia and monk fruit, can ease the transition. Be sure to stay away from artificial sugar substitutes, such as aspartame and saccharin.

Rule 7: Supplement your diet when needed

When switching to a ketogenic diet, you may experience something known as “the keto flu” characterized by flu-like symptoms such as nausea, headaches, fatigue, and dizziness. This is because your body shifts from burning glucose to fatty acids. Although this is commonly experienced within the first few weeks of the diet, staying hydrated and supplementing your diet with electrolytes and magnesium can help counteract some of these side effects over the long term. (7) Supplements to consider for the ketogenic diet include electrolyte and magnesium products.

Another side effect commonly experienced in the early stages of a ketogenic diet is low energy. B vitamins and greens powders with chlorophyll and chlorella can help provide the body with essential nutrients and an extra boost of energy. Furthermore, vitamin and mineral deficiencies have been noted as a potential negative side effect of the ketogenic diet. (7) Although a well-planned diet will prevent micronutrient deficiencies, taking a multivitamin can help ensure the body is getting all the nutrients it needs to function optimally.

To find out more about how supplementation can support a ketogenic diet, visit our blog.

Is the keto diet safe for you?

Studies have demonstrated the beneficial effects and safety of a short-term ketogenic diet for up to 6–12 months with a gradual transition back to a standard diet. While the short-term side effects of the ketogenic diet, such as the “keto flu” have been discussed, some long-term keto diet side effects have also been noted. These include hepatic steatosis (fatty liver), hypoproteinemia (low blood protein levels), and kidney stones. Due to the diet’s possible effects on the kidneys, it’s essential to monitor renal function when you are on the plan. (7)(12) In some cases, monitoring bone density may also be recommended as progressive reduction in bone mineral content as has been observed in children with epilepsy on a long-term ketogenic diet. (12)

In addition, contraindications exist for a number of health conditions including liver failure, pancreatitis, fat metabolism disorders, and porphyrias, as well as primary carnitine deficiency, carnitine palmitoyltransferase deficiency, carnitine translocase deficiency, and pyruvate kinase deficiency. Furthermore, individuals with diabetes who are considering following a ketogenic diet should consult a healthcare practitioner: if insulin or other hypoglycemic medications have not been modified to account for carbohydrate restriction, severe hypoglycemia may occur. (7)

While the benefits and safety of the ketogenic diet have been well-reported, literature pertaining to effects related to a short-term diet has so far been limited (up to 2 years). (7) Therefore, it’s difficult to conclude if there are any negative implications associated with long-term ketogenic diet use. It has also been questioned whether the benefits of the ketogenic diet are able to endure over a long period of time. As weight gain following the termination of many weight loss diets is common, it has been discussed whether a short-term ketogenic diet will support weight loss even after individuals are no longer in a state of ketosis. One study found that individuals who followed the ketogenic diet for two brief periods separated by the Mediterranean diet for maintenance demonstrated improvements in health risk factors without regaining weight. (12)

The bottom line

In the end, if you’re considering trying any therapeutic diet, it’s important to consult a healthcare practitioner to ensure the diet is right for you. Your practitioner can help plan your diet and monitor your progress to ensure the diet is followed safely and effectively.

If you’re a woman in Ontario, Canada and are looking to lose weight and gain energy in a healthy, sustainable way, contact Dr. Linda L. Brown, ND at

You can also find us at

Virtual appointments are available.

Contact us for a free 15-minute consult to see if we’re a good fit!