Tuesday, April 16, 2024


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How can a high fat diet make you lose weight? The keto diet (or ketogenic diet) has the answers, but it needs a lot of caution.

“Are you on keto?” my friend asks me when I tell her that I’ve cut carbs to a minimum and have almost eliminated sugar from my diet. I look at her in wonder. The ketogenic diet is all the rage, she tells me. She knows at least two people who do it and have lost a lot of weight.

I’m not sure if people who follow the ketogenic diet today know that it was originally designed for epileptics because it has been shown to significantly reduce seizures. 

What is the keto diet and how does it work?

Ketogenic is a diet very low in carbohydrates, moderate to low in protein and high in fat . Fat intake  can reach 70-80% . It was designed in the 1920s for therapeutic purposes. It is based on the following mechanism: When the body does not find carbohydrates (glucose) to burn and produce energy, it burns fat.

The metabolism of fats that occurs in the liver produces some substances called ketones . Ketosis, the metabolic state in which the body burns fat for energy, gets its name from them. Researchers found that ketosis significantly reduced epileptic seizures. Several patients, especially young children, were then able to regain a normal life with little or no medication.


Keto diet

unsplash  tijana drndarski


Today, ketogenic is considered one of the smartest diets for weight loss. It forces the body to burn fat and thus get rid of adipose tissue and extra pounds. Because it allows only a low percentage of carbohydrates, the foods to include in the diet are meat, fish, poultry, whole milk, eggs and non-starchy vegetables.

In other words, potatoes, cabbage, carrots, corn and peas are prohibited. Great care is needed in fruits, as just 1 apple has more than the average daily dose of carbohydrates that one should consume (about 20 g) and in cereals which are prohibited. 


The diet is based on the finding that a low-carb, high-fat diet can be more effective than a low-fat diet. A typical ketogenic diet plan includes: 80% fat, 15% protein and 5% carbohydrates . It promises the loss of 1 kg of fat per week. That is, if the daily program includes 1500 calories, only 19 grams should come from carbohydrates. 

Although eliminating an entire food group from the diet is extremely difficult, ketogenic has one advantage that makes it sustainable: It does not impose strict caloric restrictions and allows the inclusion of fatty foods, such as nuts, avocados, olive oil and even bacon and sausages! 

Short and long term effects

Clinical dietitian – nutritionist Eva Tsakou notes: “It is a diet pattern that can be followed for a short period of time to reduce weight. However, this is also based on creating a caloric deficit. That is, you end up taking in fewer calories than you burn because of the greater satiety caused by the high fat and protein. It seems, therefore, that in the beginning you can quickly reduce your weight, due to the increased loss of fluids . But in the long term its results are the same as any other diet with a caloric deficit. In addition, due to the limited variety of foods, you will quickly become bored with the repetition and quantity of foods and may be driven into even greater calorie restriction. As for the health effects, its application for a short period of time can improve some values, such as cholesterol and sugar. However, we do not have research data on these values ​​after a long period of time.”

The pros of the keto diet

  • Proponents claim that ketones are a “cleaner” source of energy than fast-burning carbohydrates. That’s why the diet improves mood and gives energy. 
  • Sugar and insulin are better controlled. Ketogenic can be beneficial for diabetics and people with diabetes predisposition if applied for a short period of time. 
  • Positive results in the treatment of neurological diseases, such as Alzheimer’s disease, Parkinson’s disease and sleep disorders.
  • Reduction of oxidative stress and inflammation.

The cons of the keto diet

  • Not all scientists agree on the suitability of this diet because: 
  • This is an unbalanced diet, rich in animal products, which do not protect against diseases such as cancer. 
  • A build-up of ketones, which are emergency fuel sources and are acidic, can take a toll on the body. How; Depleting calcium from bones. 
  • It involves a risk of dehydration and kidney stone formation, due to the lack of carbohydrates, which contribute to fluid retention by the body. When carbohydrates are excluded, more fluids are eliminated from the body. At the same time there is a loss of electrolytes, leading to fatigue, muscle aches and exhaustion. 
  • Saturated fat may lead to an increase in bad cholesterol, which causes atherosclerosis. 
  • The possibility of constipation increases due to the minimal fiber.
  • In women, there is a chance that menstruation will be disturbed due to minimal carbohydrates.
  • In many cases, due to sudden weight loss, it seems that muscle mass is also lost.


Ketogenic diet



What you should watch out for

  • If you decide to follow a ketogenic diet, you must consult your doctor. Especially if you suffer from any chronic diseases, such as type 1 and type 2 diabetes, or heart disease. You should also check your cholesterol levels with frequent blood tests if you already have elevated values. 
  • It is absolutely necessary to drink plenty of water in order to avoid dehydration, constipation and fatigue.
  • It is useful to increase your salt intake, as salts are also lost with frequent diuresis. 
  • Attention is needed in the first 14 days where the body will try to adapt to the new situation. You are likely to feel intense fatigue, muscle cramps and weakness. The phenomenon is called the “ketogenic flu” and goes away once the body gets used to it. 

The importance of personalization

  • It is important to ensure an adequate intake of fiber, B vitamins and minerals (iron, magnesium, zinc), which are found in foods such as whole grains. For specific vitamins and minerals in supplements, consult your doctor or dietitian. 
  • In the maintenance phase, you should very gradually introduce carbohydrates into your diet, so that you do not suddenly gain the pounds you lost and do not stress the body (about 20 g of carbohydrates per week).
  • The ketogenic diet requires personalization. To see the benefits of using ketones, the proper fat-to-carbohydrate ratio must be achieved, which is not the same for everyone. That is, the percentage of fat in the diet should be individualized. Arbitrarily reducing carbohydrate intake does not constitute a ketogenic diet. 

Keto diet and brain

The fuel source of the brain and nervous system is glucose. In a ketogenic diet, however, the low amount of carbohydrates deprives the body of glucose. This prompts the body to run on fat as its main source of energy.

Fats alone are unable to cross the blood-brain barrier and leave the brain low on fuel, which would progressively lead to a “shutdown” of the nervous system. However, ketones resulting from fat metabolism in the liver cross the blood-brain barrier. Ultimately, they provide the brain and nervous system with a second source of fuel, which is shown to be better for certain nervous system conditions. 


As Ms. Tsakou told us, there is very little scientific data regarding the effectiveness and risks of the ketogenic diet, as the research involves a small sample and implementation of the diet for a short period of time. A ketogenic diet plan should necessarily be drawn up by a licensed dietitian, so that it is personalized and based on the medical history of each dieter.



  • Fats: olive oil, margarine, nuts, seeds, avocados, olives, tahini, fatty fish, poultry fat, cocoa butter
  • Dairy products: hard cheeses, butter
  • Protein: red meat, poultry, bacon, fish, eggs, tofu
  • Vegetables: mushrooms, spinach, broccoli, Brussels sprouts, asparagus, peppers, onions, garlic, cucumber, celery, artichokes, cauliflower 
  • Other: nuts, dark chocolate (90% cocoa solids), cocoa powder, unsweetened coffee and tea, vinegar, unsweetened beverages, mustard, herbs and spices

In very small amounts: 

Rice, pasta and wholemeal bread, starchy vegetables, fruit, sugar, sweets, honey and legumes.

Eva Tsakou is a dietitian – nutritionist.

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