The ketogenic diet for weight loss: the science behind the ketogenic diet

In the search to lose weight, we can choose all kinds of methods, diets, habits … The ketogenic diet, as numerous studies have shown, is capable of making us lose weight. The metabolic mechanisms behind it explain why.


But not all that glitters is gold. Like all tools, using it inappropriately, or at the wrong times, can have its consequences. Today we talk about why this nutritional pattern works for weight loss and why we shouldn’t use it for that purpose except at specific times.

What are ketone bodies?

The name of a ketogenic diet means that it creates ketone bodies. Ketone bodies are a metabolic product generated when the body does not have carbohydrates available to burn quickly. Therefore, this diet rejects carbohydrates as much as possible, using fat as an energy source and increasing protein. Let’s do a quick review of what happens in our bodies when we need energy.

Imagine muscle as powerful machinery that needs fuel. The fastest and most immediate fuel is the blood glucose concentration. If our blood glucose is very low and energy expenditure increases, the muscle soon runs out of sustenance. Then you will take advantage of another store of stored carbohydrates: glycogen. If the body also runs out of this reserve, then it will revert to another metabolic pathway: ketosis.

Ketosis occurs mainly in the liver, where fat will be transformed into ketone bodies after a short trip. Fat is generally used for energy through the Krebs cycle. However, in desperate situations, some fatty acids components go to a faster but less efficient metabolism.


In it, “special” molecules are formed (such as acetoacetyl coenzyme A) that end up giving acetone, acetoacetic acid, or beta-hydroxybutyric acid. Or, in other words, ketone bodies. Ketone bodies are used with the immediacy of glucose, for energy, at the expense of fat, which will explain some of the evidence that we will talk about.

How does the ketogenic diet work?

Ketogenic diets have been shown in several studies to be efficient when it comes to losing weight. This is based on three facts. The first, which we talked about before, is that this diet takes advantage of fats quickly, using a more inefficient route. Inefficient, in this case, it suits us because it indicates that we need more fat to produce less energy.

The second is that it prevents hypercaloric intake and fat accumulation due to excess carbohydrates. Regular diets contain a large amount of carbohydrates (a large amount does not imply too many, it all depends on the diet). With a ketogenic diet, it is impossible to accumulate excess blood glucose and fat from a surplus of energy.

The third, according to some studies, is that the ketogenic diet helps to maintain levels of satiety, helping to better control intake in patients who practice it. Following this trio of effects, studies have shown that it can be helpful in reducing obesity. Others, produced by the same researchers from the Physiology Laboratory at the University of Padua, have approached the question from different angles.

In general, the answer is positive, especially with obese patients. Other studies, such as the meta-analysis carried out by the Basel Institute of Clinical Epidemiology, indicate that ketogenic diets have, at least, a similar effect on weight loss as a low-fat diet. This has also been confirmed by another meta-analysis performed by the Federal University of Alagoas’s experimental nutrition laboratory in Brazil.

Besides, systematic reviews also support appetite suppression, such as the Boden Institute for Obesity, Nutrition, Exercise and Eating Disorders meta-analysis at the University of Sydney. Let us remember that meta-analyzes are the studies that best support the evidence since they compile dozens or hundreds of works and analyze their methodology and conclusions.

The ketogenic diet does not work in all cases.

From what we’ve seen, the ketogenic diet relies on three things to be effective. The evidence also shows positive results. So why not use it for any circumstance? Ketosis, as we have already said, is an exceptional state of emergency. It is not a physiological situation that we should take lightly.

Ketosis occurs because our hearts and brains need a constant supply of glucose. If this is not available, the supply cannot be stopped, as would a muscle (which can afford to fail). These two organs turn to ketogenic bodies as a “desperate” measure. If for whatever reason, this contribution fails, we have a severe problem.

On the other hand, precisely to prevent this from happening, ketosis can occur in an exacerbated way. This can lead to ketoacidosis. This phenomenon happens because ketone bodies are acidic and lower the blood’s pH; that is, they make it acidic to dangerous levels. Also, they affect various organs to their standard metabolic processing.

In common cases, ketoacidosis has dangerous but not serious symptoms: dizziness, malaise, bad breath, muscle failure, frequent urination and thirst for a whole day or more, headache, nausea and vomiting, dizziness, breath sweetness, and stomach pain … In the most severe cases, such as ketoacidosis caused by diabetes, or alcoholic ketoacidosis (which occurs as a result of alcohol withdrawal syndrome and a lack of intake), which can reach the cerebral edema (accumulation of fluid in the brain), kidney failure or heart problems.

When and how should we use it?

The ketogenic diet should be used as a tool for certain circumstances. It must be made clear that the whole approach to this type of diet does not fit with the idea of ​​healthy habits. A balanced and healthy diet includes legumes, cereals, fruits, and a series of foods rich in carbohydrates. Ketogenic diets, however, bypass these macronutrients to induce ketosis.


This can be useful for weight control, as we said, in patients with obesity. They can also help us if we plan them with a specialist to avoid the problems we mentioned. Another utility of the ketogenic diet is to use it in the last stage of muscle definition.

In this case, it is convenient to combine it with a hyper-protein diet to avoid muscle mass loss and maximize its growth. Finally, maintaining a state of permanent ketosis is not advisable, although it does not have to be a problem when well managed. But always with strict control.

In case of diabetes or other metabolic problems, the ketogenic diet is automatically ruled out. We insist it is a kind of tool for specific situations, something to use only with an expert’s supervision and not a mere “miracle diet” to lose weight.


Images | Unsplash, Wikimedia




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Rohit Pathak

Rohit Pathak

Blogger and Affiliate Marketer

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