Is the Keto diet healthy?

In the last article, we were looking at some of the shortcomings of the Paleo diet. In this article, we will have a critical look at a famous diet many people are using for rapid weight loss: the Keto diet, also known as the Atkins diet. We will see why this diet has profound effects on your body’s metabolism, and that it can cause serious health damage.

What is the keto diet?

The typical keto diet avoids foods like fruits, starchy vegetables (such as potatoes, sweet potatoes, and pumpkin), legumes, and whole grains. It includes large quantities of meat, eggs, cheese, milk, nuts, seeds, leafy greens, non-starchy vegetables, and vegetable oils.

The typical keto diet is an extreme diet, with very low carbohydrate intake of just 5% of total calories (or as little as 20 grams per day), and very high fat intake of up to 80-85% from calories.

Those are extreme values! Our brain alone needs about 120 grams of glucose daily. In a healthy diet, 40-70% of calories should come from carbs and just 20-35% from fat. In short, a paleo diet provides way too much fat and way too less carbohydrates. Why is that bad?

The state of ketosis

Glucose, derived from carbohydrates, is the preferred fuel for our body. In order to supply our cells with energy when carbs are depleted, the body can break down protein and fat. Let’s look at fat first. Anyone following the keto diet, aims to reach the state of ketosis. Ketosis is a process that is meant for actual emergencies, such as starvation, to keep the body working. The alternative ‘fuel’ that is produced is not glucose. It is called ‘ketone bodies’. Those ketone bodies can fuel many cells, and especially the brain cells, in those situations. When we are in a prolonged state of carbohydrate depletion, the body will produce excessive amounts of ketone bodies.

Ketone bodies are acids. At high levels, they can make your blood acidic.

Ketone bodies are chemicals, such as acetone (you don’t want to have huge quantities of nail polish remover in your body, right?). In extreme prolonged cases, a keto diet can lead to a state of ketoacidosis, which can lead to confusion, motor impairment, fatigue, nausea, vomiting and, in severe cases, even coma and death. This risk is increased if you follow a very strict keto diet combined with very low calorie intake.

Energy from protein

There are also cells that cannot use ketone bodies for energy. In order to supply those glucose-dependent cells with glucose when carbs are depleted, the body can make glucose from protein as well. This process is called ‘gluconeogenesis’ – ‘making new glucose’. In most cases, the keto diet provides sufficient amounts of protein.

proteins keto diet

However, if protein intake is too low on the keto diet, the body can ‘steal’ protein from our blood first, and then from our organs.

This can cause organ damage in severe cases. Moreover, the proteins that are ‘stolen’ cannot be recycled anymore for their original function, namely, to make new cells, repair tissue damage and support the immune system.

Serious health consequences

A very strict keto diet can be dangerous for your health. In the short run, it can result in vitamin and mineral deficiencies, electrolyte abnormalities, hypoglycemia (low blood sugar level), hyperlipidemia (too many fats in your blood), constipation, microbiome changes, and restricted arterial function. In the long run, it can lead to gastro-intestinal problems, kidney stones, osteoporosis, alterations in the immune system and increased heart disease risk.

Low-carbohydrate diets are associated with a significantly higher risk of all-cause mortality.

If your health is valuable to you, please don’t follow a strict keto diet for a longer period without consulting a registered dietician first. Yes, in the short-term it can help you to lose weight. But those benefits do not outweigh the health risks that may come with it.

Weight loss

Many people experience rapid weight loss on a ketogenic diet. Unfortunately, the weight loss does not come from body fat. I mean, why would you expect to lose fat if your diet consists almost exclusively of fat?

rapid weight loss keto diet

The weight loss is primarily a depletion of glycogen, water, lean mass and protein.

Moreover, a diet like this is not sustainable. The keto diet has very low compliance rates. People just can’t eat like that for a longer period. The ketone bodies suppress hunger, but as soon as you start to eat more carbs again, the body goes out of ketosis. It will crave for carbohydrates and the appetite returns with all its power. Hello jojo-effect!

Medical keto diet

Ketogenic diets are used to treat pharmacoresistant epilepsy, as well as potentially other neurological and rare metabolic disorders.

This is always supervised by physicians and registered dieticians because of the risks.

It is recommended that people wishing to start a ketogenic diet, especially those with comorbidities such as diabetes mellitus type II, first consult their physician to discuss the risks and benefits.


If you want to lose weight by changing your diet, you should not focus on one particular macronutrient group, such as very low carb diets. The best way to lose weight is to decrease your total energy intake below your energy needs.

A reduction of about 500 kcal per day results in a healthy weight loss of about 0.5 kg per week).

You should also focus on consuming the healthy types of fat and carbohydrate. Replace refined carbohydrate foods with whole grain foods. Replace saturated fats with unsaturated fats. A healthy plant-based diet can help you to reach those goals.