The Ketogenic Diet

Information Prepared by Victoria Hanson

What is the Ketogenic Diet?

The ketogenic diet is an extremely high fat, adequate protein, and extremely low-carbohydrate diet.  In the absence of carbohydrates, the body undergoes ketosis. The body will use ketones from fats for energy instead of glucose which are broken down from carbohydrates.

The standard ketogenic diet involves consuming anywhere between 20-50 grams of net carbs per day with moderate protein sources and a high fat intake. It involves consuming 5-10% of your calories from carbohydrate sources, 20-25% from protein, and 70-80% of your calories from fat.

Unlike most other fad diets, the keto diet is a therapeutic diet.  Mild ketone body production has actually shown benefits in some disease states.  The ketogenic diet is prescribed to some patients with epilepsy to reduce symptoms and medication.  When epilepsy patients are recommended this diet, they are very carefully monitored by doctors and dietitians, not following the advice of celebrities or social media.  Today, the Ketogenic Diet is under research for its ability to help in the treatment plan of certain cancers.

The Restrictive Nature of the Ketogenic Diet

Like most fad diets, the ketogenic diet is extremely restrictive.  It involves essentially eliminating one of the three macronutrients.  Foods eliminated on the ketogenic diet include legumes, grains, most fruits, starchy vegetables, and alcohol.  Therefore, this diet is extremely difficult to stick to and very expensive.  This may result in starting the diet followed by quitting the diet due to the difficulty of sticking with it.  Therefore, fast weight regain can follow resulting in yo-yo dieting.  People who have tried the ketogenic diet and stopped may feel as though they have failed when in reality, it’s the extremely restrictive nature of the diet that has failed.

Adverse Effects of the Ketogenic Diet

Research shows that the ketogenic diet may have negative effects on renal function caused by a large amount of nitrogen from animal sources that needs to be excreted.

In the short term, ketosis can cause some people to feel constipated, nauseous, fatigued, and experience headaches.  The ketogenic diet can also cause mineral and vitamin deficiencies.

Most people can undergo a ketogenic diet without going into ketoacidosis.  However, research also shows case evidence of the ketogenic diet inducing ketoacidosis.  A build-up of ketones can cause an imbalance that leads to excessive acid production and can change your body's pH.  The human body's pH is very carefully regulated and fluctuations in its pH can be extremely detrimental.  There is evidence that a combination of fasting, low-carbohydrate diets, and alcohol consumption could put your body into a ketoacidosis state.  Ketoacidosis is a life-threating condition.

Weight-Loss on the Ketogenic Diet

The ketogenic diet has become very popular in healthy populations as a weight loss diet.

Carbohydrates require more grams of water to digest and store compared to fats.  Therefore, if you are to stop consuming carbohydrates and fat becomes your main source of fuel, your body will retain less water.  This can result in extremely rapid weight loss when starting the ketogenic diet due to water loss.  This can lead dieters to think they are rapidly losing fat when in reality their fat mass has not changed.

Carbohydrates, Fats, Protein? Which one is bad?

In the 1970’s, death related to cardiovascular health had skyrocketed in North America.  Scientists concluded that the high fat Westernized diet was to blame and marked fats as ‘bad’ foods. As a result, low-fat, high carbohydrate diets became extremely popular.  The theory was by eliminating fat in our diet we would lose weight and reduced our incidence of chronic disease.  Food companies in North America made fat-free products and added massive amounts of sugar so taste was not affected.  As a result, our rates of chronic disease did not decrease.  The carbohydrates North Americans were eating were refined, processed, and did not have much fiber.

Today, we have completely flip-flopped.  Many fad diets promote eating high amounts of fats and low amounts of carbohydrates. These diets include Atkins, Paleo, and its most extreme form: Ketogenic Diet.

In reality, the most nutritious diet is one that contains balanced amounts of carbohydrates, fats, and protein, as each macronutrient has roles in the body.  The types of these macronutrients you consume is more important.  For carbohydrates: maximize whole grain options for their fibre content, get a variety of sources, and eat lots and a variety of fruits and vegetables.  For Fats: choose unsaturated sources more often and avoid trans fats.


I would not recommend this diet as a weight-loss strategy.  Restricting an entire macronutrient and labelling it as ‘bad’ has a negative impact on our relationship with food.  Restrictive diets are extremely difficult to stick with in the long run and often result in fast weight regain.

Questions about your diet and nutrition needs? All University of Guelph students have access to Student Wellness Services nutrition services (free and fee-based options are available). Students can access these services in three ways: