Being on a diet is not the most difficult part. Neither is avoiding re-gaining all the pounds lost. The hardest part is to understand which diet is the most suitable for you in the long run. A diet should modify some incorrect food behaviors without completely overturning your daily life, which would jeopardize your willingness to be on a diet. Every diet regimen has a logic, a basic scheme on which all the nutritional strategy is based; following our lifestyle, attitude, goals and needs, it’s up to us to choose which diet better respects these 4 aspects. According to the International Food Information Council, Americans’ food habits have changed and the ketogenic diet has been one of the most chosen health regimens to lose weight, together with intermittent fasting.

What is a ketogenic diet?

But what exactly is the ketogenic diet? Best known as the “keto diet”, this regimen was created by Russell Wilder, a medical doctor, in the early 1920s as the main treatment for drug-resistant epilepsy in children. However, 10 years later, more efficient drugs were discovered and the keto diet lost its appeal until the late 70’s, when it came back in vogue. According to the Dietary Guidelines for Americans, the ketogenic diet is considered a very low carbohydrate diet, consisting of  healthy fats, adequate proteins, and very-low-carbohydrates, allowing only 20-50 grams of non-fiber carbohydrates per day. 

Keto chicken breast with cauliflower rice and spinach, Quebec, Canada
A keto diet follows a high fat, low-carb eating pattern. An example of a keto meal is this chicken breast with cauliflower rice and spinach.

What are carbohydrates and why does the keto diet restrict them?

The idea with this diet is to deprive the body of ingested carbohydrates. But why are those macronutrients so demonized? Because they have a clear link with weight gain and obesity, thanks to their influence on insulin level fluctuation and hunger. Plus, a high-sugar diet is connected with diabetes onset and its associated comorbidities (hypertension, cardiovascular disease, cancer). Sugars, starches and dietary fibers all belong to the carbohydrate family. Carbohydrates are molecules that can be classified as simple or complex, based on the number of sugar units it contains. Single or double sugar molecules are known as simple carbohydrates, examples are:

  • glucose = found in syrups and honey
  • fructose = found in fruits
  • lactose = contained in dairy products 

A high number of sugar units linked together are known as complex carbohydrates and are:

  • starches (amylose and amylopectin) = found  in potato, rice and corn
  • fibers (cellulose) = found in whole grains and legumes

Once ingested, the body breaks down all the complex carbohydrates to obtain glucose (but also fructose and galactose), the number one source of energy for the  brain and body. 

How does the keto diet help with weight loss?

Now it’s time to really pay attention! The aim of the keto diet is to enter a ketosis state, meaning that the main energy source of the body is shifted from carbohydrates (glucose) to fats. With the keto diet, the total amount of carbohydrates eaten is dramatically reduced (to less than 50 g/day) and so it is up to the body to find a way to create energy for all its different cellular and metabolic processes. The body’s strategy to face carbohydrate depletion is to mobilize all the energy stored in the tissues. One move is to mobilize the glucose stored in the liver in the form of glycogen. Glycogen is reduced to glucose (thanks to a bunch of different chemical reactions called glycogenolysis) and then rapidly pumped into the bloodstream to give the body some ready-to-use energy. A second move is to mobilize all the fats stored in the adipose tissue in the form of triglycerides. Those triglycerides are split into fatty acids, which eventually give rise to ketone bodies. This two-step strategy put in play by the body is the core around which all the keto diet strategy is based.  

Concept-weight loss
The goal of the keto diet is to force your body to use fats instead of glucose to derive energy. This increases fat-burn and leads to weight loss.

Guess what? Those triglycerides deposits that the body attacks are none other than the muffin top of your belly! This is the key of the whole keto diet: since the body can’t sustain itself without glucose, it must mobilize deposits to obtain it, which leads to a decrease in fat storage and, ultimately, weight loss. 

This is the first advantage of following the keto diet: you will see results in weight reduction very quickly (up to 10 lbs in 2 weeks or less) and this will motivate you to stay on this  diet. The motivation to stick to it also comes from the fact that the keto diet is rich in tasty food; giving you the chance to eat all kind of fats (lean meats, lard, butter, whole milk, cheese, avocados, nuts, olive and avocado oil, etc). This makes people’s perception of not being on a diet and makes that regime appear unrestrictive: another great advantage!  

Other benefits of the keto diet

Beside being easy to stick to, other advantages of this diet are:

Improvement in insulin sensitivity and reduction of blood sugar levels in both obese and diabetics

This is attributed to ketone bodies being released into the bloodstream which are able to induce what is called “nutritional ketosis”. This consists of a massive production of energy in the form of ketones, which are easily utilized by muscles, heart and brain, without any alterations in blood pH.

Reduction in blood pressure and amelioration of hypertension

 a 2013 study found that following a keto diet for a time period ranging from 3 to 36 months, helped reduce systolic blood pressure in 95% of dieters. For this amelioration in blood pressure, we should thank ketone bodies. Again. 

It has also been shown that ketone bodies stimulate the antioxidant defense system of the body reducing both free oxygen radicals and, consequently, DNA damage.  

Decreased sense of hunger

There are different studies that link the blood presence of ketone bodies with reduced hunger, but mostly in animals. However, this 2008 study shows that hunger and food intake are reduced in people following the keto diet. This decrease in appetite is probably due to reduced insulin level fluctuations due to an almost total absence of sugars, and to the anorexic effect of ketone bodies.

Shot of a young man taking his blood pressure while sitting on the sofa at home
The keto diet has been shown to reduce blood pressure, increase insulin sensitivity, and reduce blood glucose levels.


Side effects of the keto diet

Unfortunately, all that glitters is not gold. Both the American Diabetes Association and the European Association for the Study of Diabetes support the use of the keto diet for weight loss and glycemic control but only for a short-term. The keto diet, especially if followed without medical supervision, can have severe disadvantages and setbacks.

Side effects of the keto diet have been reported  even in the short-term period (2 – 4 days). The totality of symptoms goes by the name of “keto flu” and includes: headache, fatigue, dizziness, irritability, nausea, vomiting, constipation, and insomnia. This clinical picture is due to the body adapting to bloodstream ketone bodies and will resolve autonomously after a few days or weeks as the body adjusts to the new regimen. You can help it by drinking more fluids.

Diabetics may also experience two major drawbacks: hypoglycemia, due to reduced sugar intake if the insulin load is not adjusted to the new diet regime, and ketoacidosis. The latter occurs when the ketone body production is so high that, once in the bloodstream, blood pH goes down until it becomes acidic and the glucose concentration rises. This acidic condition is extremely dangerous for a diabetic person, involving fruity-scented breath and/or shortness of breath, excessive thirst and frequent urination, nausea, vomiting, and often confusion. It’s fundamental to recognize this state since untreated diabetic ketoacidosis can lead to death. Ketoacidosis is dangerous for type 1 diabetics and for those with type 2 diabetes who have little or no insulin production, and it’s also dangerous for those with gestational diabetes. Yet, it has been observed that patients affected by type 2 diabetes show less severe acidosis, probably due to a better hormone regulation system compared to type-1 diabetics.

It was also found that people following a keto diet show augmented renal functioning which reflects in an increased need to pee. This is an alarm sign that the body is sending. The large amount of proteins ingested during the keto diet, causes the kidneys to double their workload to excrete them. This kidney overload, if protracted over time, may lead to renal injury. 

The liver also faces increased workload since it is the top player in producing ketone bodies from fatty acids. A recent article showed that long-term keto could affect liver health and also lead to non-alcoholic fatty liver disease.

After all these considerations, pros and cons, the take home messages for you are: never underestimate the potential dangers of every food regime, especially if affected by pre-existing conditions, and always ask for help from a professional. 

The above is not medical advice. Prior to participating in any wellness challenge, you are encouraged to consult a qualified health professional.