Ketogenic diet: how to do it well, menu, pros and cons

What is the ketogenic diet?

The ketogenic diet, also commonly known as the keto diet or keto diet, represents an eating method aimed at reduce carbohydrate intake and increase fat intake, putting the body into a metabolic state known as ketosis. In recent years, this diet has gained more and more popularity. 

There are several approaches to the ketogenic diet, each with variations in calorie content and the proportion of macronutrients, including carbohydrates, fats and proteins. 

The primary objective of this diet is induce ketosis, a process by which the body burns fat for energy. 

Ketosis is believed to promote weight loss and bring health benefits, such as lowering blood sugar and improving cholesterol.

What is ketosis? 

Ketosis is a state in which the body uses fat as its main source of energy, producing molecules called ketones. 

Normally, the body relies on carbohydrates for energy, and insulin is responsible for storing blood sugar, called glucose, for this purpose. However, when carbohydrate intake is reduced, insulin levels decrease, leading to a series of metabolic changes.

Initially, glucose is stored as glycogen in the muscles and liver, available for use when needed. 

However, after a few days of low carbohydrate intake, these glycogen stores become depleted. 

In this phase, the body begins to use stored fats as its primary source of energy. The breakdown of fat produces free fatty acids that are transformed in the liver into ketones, which the body can then use as fuel.

For example, intense physical activity can accelerate the depletion of glycogen stores, causing the body to enter a state of ketosis more quickly. 

In conclusion, ketosis is a natural metabolic process that occurs when the body uses fat as its main energy source, producing ketones as a byproduct.

How does the ketogenic diet work?

By reducing carbohydrate intake in the diet, insulin production is also reduced, which can have significant health benefits, especially in people who consume excessive amounts of high-glycemic index carbohydrates, i.e. foods that cause excessive blood sugar levels after ingestion. blood sugars.

Despite the weight loss, low blood sugar, and high blood ketones, some studies have raised concerns about the long-term effects of the ketogenic diet. 

For example, a study conducted on rats showed that sustained adoption of a keto diet for 60 days caused side effects such as metabolic acidosis, anemia e reduction in the levels of antioxidant enzymes in the blood. 

These findings indicate that while the ketogenic diet may offer initial benefits, it is essential to carefully consider potential risks and monitor long-term health when adopting this diet.

Classic ketogenic diet

The classic ketogenic diet (known as cKD) has been used since 1921 to treat epilepsy in children. 

This type of diet is called “classic” because it was the first to be developed and used. cKD is a diet that provides a normal calorie intake but is high in fat and low in carbohydrates. 

It is used around the world to treat drug-resistant epilepsy, which is when conventional drugs don't work. 

cKD has been shown to have anticonvulsant effects, meaning it helps prevent or reduce seizures. 

This effect is achieved by shifting the main source of calories from carbohydrates to fats. In practice, the diet is mainly composed of fats, with a limited amount of protein and carbohydrates. 

A common ratio is 4 parts fat to 1 part protein and carbohydrate combined.

Variants of the ketogenic diet

• Ketogenic hyperlipidia e hyperproteic (like the Atkins diet)
• Ketogenic hyperlipidic e normo-hypoprotein (such as the modified Atkins diet to treat drug-resistant epilepsy)
• Ketogenic hypolipidic e normal protein (such as VLCKD, used to treat obesity).

Ketogenic diet: the extremely low-calorie variant

A popular variant of the ketogenic diet is the very low-calorie ketogenic diet (VLCKD), which has recently been suggested as a dietary strategy for managing obesity. 

This type of diet is characterized by a low carbohydrate intake, with less than 50 grams per day, and a moderate amount of protein, usually around 1-1,5 grams per kilogram of ideal body weight. As for fats, the daily intake is around 15-30 grams. 

It is important to note that this diet provides a very low calorie intake, usually between 500 and 800 calories per day. This diet aims to promote ketosis and weight loss through calorie restriction and carbohydrate elimination.

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Contraindications of the Keto diet

In recent years, the ketogenic diet has gained considerable popularity, especially among those seeking to lose weight and reduce insulin resistance in both type 1 and type 2 diabetes. 

However, concerns arise regarding long-term effectiveness in weight loss and potential adverse effects on kidney function and blood cholesterol levels due to increased protein and fat intake.

Particularly in the case of diabetes, increased intake of animal protein, but not plant protein, has been associated with insulin resistance and increased health risk. 

Additionally, foods rich in animal protein also contain other nutrients, such as saturated fat, heme iron, and nitrites, which could contribute to these results.

In addition, high-protein diets are linked to compounds produced by the fermentation of proteins by the gut microbiota, which may include pro-inflammatory metabolites.

Side effects

In the short term, it is common to experience some symptoms when transitioning to a ketogenic diet. 

These may include easy fatigue during exercise, reduced mental energy, increased hunger, sleep disturbances, muscle cramps, constipation, bad breath, nausea and stomach pain. 

However, most of these disorders tend to decrease after the first few days of adaptation.

Ensuring adequate fluid and electrolyte intake can help counteract some of these symptoms. Long-term adverse effects include:

• Nutritional deficiencies: Keto diets are very restrictive and can lead to nutritional deficiencies with inadequate intake of essential vitamins, minerals and phytochemicals.
• Digestive problemsHigh-fat, low-fiber diets can cause digestive problems, such as constipation, diarrhea, and swelling.
• Kidney stones: A high-fat, low-carb diet may increase your risk of developing kidney stones.
• Heart disease: A ketogenic diet may increase your risk of heart disease due to its high saturated fat content and lack of fiber.
• Muscle loss: Rapid weight loss on a ketogenic diet can lead to muscle loss, negatively impacting athletic performance.
• Cognitive decline: The effects of low-carbohydrate diets on brain metabolism can potentially lead to cognitive decline.

It is important to note that, although the ketogenic diet may offer benefits in improving the ability to utilize fat, especially in endurance sports, some authors suggest that sports performance at high levels may not be optimal in the absence of adequate carbohydrate intake. 

This demonstrates the importance of carefully evaluating individual needs and finding a balance between adaptation to ketosis and the specific demands of physical activity.

When it is not recommended to follow the ketogenic diet

According to recent studies, during pregnancy and breastfeeding, women should prudently avoid following a ketogenic diet. 

This is because a negative effect on cognition has been observed in rodents exposed to ketosis during early life through young adulthood. 

However, it is important to note that no adverse neurodevelopmental effects have been found in children who have used a ketogenic diet to treat epilepsy.

Categories of people for whom a ketogenic diet may not be recommended include:

1. People with severe liver or kidney disease: Because the ketogenic diet can affect lipid and carbohydrate metabolism, it may not be safe for those with liver or kidney problems.

2. Pregnant or breastfeeding women: During pregnancy and breastfeeding, the body has specific nutritional needs that may not be adequately met with a ketogenic diet.

3. People with eating disorders: Calorie restrictions and a focus on certain food groups could exacerbate problems for those suffering from eating disorders such as anorexia or bulimia.

4. Individuals with certain medical conditions: Some medical conditions, such as type 1 diabetes, may require more careful adjustment of your diet, and a ketogenic diet may not be right for everyone.

Ketogenic diet pros and cons

The ketogenic diet involves severe restriction of carbohydrates, instead allowing for ample intake of fats, including saturated fats. This diet has attracted great interest, with many supporters and just as many opponents. 

While the ketogenic diet can lead to rapid and significant weight loss and improvements in biomarkers, such as reductions in glycated hemoglobin in patients with type 2 diabetes, it can also cause a significant increase in “bad” LDL cholesterol levels, a fact that makes many doctors hesitant to promote it.

In addition to this, two human studies have highlighted potential harmful effects of ketone bodies. In a general population-based cohort study, individuals aged 54 ± 12 years, a positive correlation was found between circulating ketone bodies and all-cause mortality. 

It was found that increased mortality was also linked to increased liver fat index, an indicator of non-alcoholic fatty liver disease, and this relationship was partly mediated by circulating ketone bodies..

Another study reported a dose-response relationship between increased body concentrations of ketones and a 50% increase in all-cause mortality among black and white Americans.

Although the ketogenic diet has traditionally been considered beneficial for weight and glucose control, with few side effects and good adherence and tolerance even in older adults, concerns arise regarding its health consequences. 

The main problem concerns the variation of versions of the ketogenic diet and the different effects of its essential components. Consequently, the consequences of the ketogenic diet may extend beyond the action of circulating ketone bodies.

How long can you do the ketogenic diet?

According to the majority of authors, the ketogenic approach should be understood as a time-limited diet. Long-term adherence to a ketogenic diet can be a challenge. 

Although this diet has demonstrated positive results in inducing rapid and sustained weight loss in obese individuals for up to two years, it is critical to fully understand its clinical impact, safety, tolerability, efficacy, duration of treatment, and the long-term prognosis after its discontinuation.

The duration of the ketogenic diet can vary considerably, from a minimum of 2-3 weeks up to 6-12 months, according to the National Library of Medicine. 

During this period, it is crucial to carefully monitor kidney function, given the changes in water metabolism and diuresis associated with reduced glycogen levels during a ketogenic diet, it is advisable to increase fluid intake to maintain fluid balance and electrolytic.

General guidelines recommend drinking at least 8 glasses of water a day, but individual needs may vary based on factors such as body weight, physical activity and climate. Some people may need to drink more than 8 glasses a day to maintain adequate hydration while on a ketogenic diet. It's important to drink water regularly throughout the day and listen to your body to determine whether you need to increase your fluid intake.

It is important to keep in mind that there are still many unanswered questions regarding the long-term effects of the ketogenic diet, especially after stopping it.

Further research is needed to explore the long-term effects of the ketogenic diet, including impacts on metabolic, cardiovascular, and neurological health, as well as its effectiveness in maintaining weight loss over time. 

Only a better understanding of these aspects will allow us to provide more precise and safe guidelines for adopting and maintaining the ketogenic diet in the long term.

How to reintroduce carbohydrates without gaining weight

When deciding to reintroduce carbohydrates after losing weight on a ketogenic diet, it is advisable to consult a dietician for personalized guidance. 

However, there are some general recommendations to follow: After following a ketogenic diet, carbohydrate replenishment should be gradual and well-planned to avoid sudden changes in blood sugar levels and other side effects. 

Here are some tips for replenishing carbohydrates safely and effectively:

1. Start slowly: Add small amounts of complex carbohydrates to your diet, such as starchy vegetables (sweet potatoes, squash, carrots) and whole grains (brown rice, quinoa, spelt). Start with one serving a day and monitor your response carefully.

2. Choose the right carbohydrates: It is essential to replenish carbohydrates carefully, favoring foods from non-genetically modified raw materials. Make a conscious choice by opting for pasta, bread and baked goods prepared with ancient varieties of durum wheat.

These foods tend to have a less drastic impact on blood sugar levels than refined foods, as the latter have a high content of refined and ultra-processed carbohydrates, and can cause unwanted blood sugar spikes. Choose foods rich in fiber, vitamins and minerals to support your overall health and promote long-lasting well-being.

3. Monitor your body's response: Observe carefully how your body reacts to the introduction of carbohydrates. Pay attention to any symptoms of discomfort or changes in energy levels, your weight and especially your fat mass and adapt the amount of carbohydrates you eat accordingly.

Should I take supplements during a ketogenic diet?  

During a Ketogenic Diet, it is essential to ensure an adequate intake of all necessary micronutrients. 

In particular, it is advisable to increase the intake of alkalizing minerals such as potassium, magnesium, calcium, with enriched foods or supplements, like our Day Up! ️

This helps balance any high production of ketones, which can have acidifying effects on the body. Making sure you get enough of these minerals is actually very important for maintaining balance and health while on the ketogenic diet.

Some nutrients, which are readily available in grains such as wheat, may have been limited while on the ketogenic diet, causing side effects such as headaches, brain fog, fatigue, irritability, nausea, difficulty sleeping, and constipation, commonly known as “keto flu". 

What is the keto flu? The keto flu, also known as “ketogenic flu”, is a series of symptoms that some people may experience when starting a ketogenic diet, and consists of the reduction of blood sugar levels and the body's adaptation to the production of ketones as the main source of energy, with symptoms such as fatigue, tiredness, headache and decreased energy. These symptoms usually disappear within a few days or weeks as the body adjusts to the new diet.

Ketone levels deemed safe

To maintain safe nutritional levels of ketosis, it is advisable to keep ketone levels in the range of 1,5-3,0 mmol/l, as recommended by researchers Stephen Phinney and Jeff Volek. These ketone levels can be monitored through urine and blood tests. 

You can measure ketone levels in your urine yourself using commercially available test kits. These kits contain test strips that react with ketones in urine.

However, it is important to note that measuring ketones in urine may not be highly precise and may not necessarily reflect ketosis levels in the blood, which is considered a more accurate method.

What to eat if you do the keto diet?

It is very important to know what foods you will eat before you start and how to incorporate more fat into your diet,” she says Kristen Mancinelli, RD , author of The Ketogenic Diet: A Scientifically Proven Approach to Fast, Healthy Weight Loss , which is based in New York City. 

Mancinelli shares his guide on choosing nutritious foods for keto here:

Protein

Ketogenic diets are not high in protein (they focus on fat), so they should be consumed in moderation.

Freely 

Grass-fed beef, fish, especially fatty fish like salmon, dark meat chicken 

Occasionally

Bacon, low-fat proteins like skinless chicken breast and shrimp. They're great to include in your keto diet, but add a sauce on top for a little fat instead of eating them plain.

May

While potentially high in fat, these protein sources can also contain too many carbohydrates, and in the case of deli meats and chicken nuggets, these typically sodium-rich foods can raise blood pressure levels.

Cured meats with added sugar (read the label), meat marinated in sugary sauces, fish or chicken nuggets

Oil and Fats

Freely

Extra virgin olive oil, avocado, avocado oil

Occasionally 

Sunflower oil, safflower oil, corn oil, butter, whole milk, coconut oil

May

Margarine, trans fats

Fruits and vegetables

Freely

Avocado, green leafy vegetables, such as spinach and arugula, celery, asparagus

Occasionally 

Leeks, spaghetti squash, aubergine, avocado, raspberries, lemon, tomatoes 

May

Potatoes, corn, raisins

Nuts and seeds

Freely

Walnuts, almonds, flax seeds, chia seeds

Occasionally

Cashews and pistachios

May

Nut butters, sweetened seeds, chocolate covered nuts

Dairy Products

Freely

Feta, Parmesan

Occasionally

Whole ricotta, whole Greek yogurt, whole ricotta

May

Milk, sweetened low-fat yogurt, ice cream

Sweeteners

Freely 

Nobody

Occasionally

Xylitol, stevia, erythrotol, artificial sweeteners

May

Agave, honey, maple syrup, white and brown sugars

Condiments and Sauces

Freely

Guacamole, mayonnaise (make sure no sugar is added)

Occasionally

Raw garlic, tomato sauce (look for the one without added sugar), balsamic vinegar

May

Barbecue sauce, ketchup, honey mustard

Drinks

Freely

Water, unsweetened almond milk, bone broth, plain tea

Occasionally

Black coffee, unsweetened carbonated water, zero calorie drinks, alcohol 

May 

Fruit juice, lemonade

Herbs and spices

Freely 

Pepper, thyme, oregano and paprika

Occasionally 

Ground ginger, garlic powder, onion powder

May

No herbs and spices are prohibited; they are generally fine to use in small quantities to add flavor to foods.

Ketogenic diet for vegetarians

Meat is a mainstay of the ketogenic diet, but that doesn't mean the diet is off-limits to vegetarians. As the high-fat, low-carb approach has grown in popularity, many vegetarians have wanted to follow the hype and have found ways to make it work for them too, by tweaking the typical ketogenic diet menu and list foods to suit their meat-free lifestyle. 

Here's what a typical day on the keto diet for vegetarians looks like:

• Breakfast with protein powder or egg-based protein pancakes and protein powder

• Snack Sliced ​​cucumber with sheep's cheese or cottage cheese with sunflower seeds

• Lunch Large salad with avocado, greens, seeds and nuts or egg omelette with herbed goat cheese and pesto

• Price Courgette spaghetti (zoodles) with pesto and tofu; sautéed vegetables with tempeh; or spinach salad with cashew crusted tofu, grilled courgettes, diced feta and extra virgin olive oil with a high polyphenolic content (Link to our oil).

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Front Nutr. 2024; 11: 1322509. doi: 10.3389/fnut.2024.1322509 ; Ketogenic diet and behavior: insights from experimental studies

Cureus. 2023 Mar; 15(3): e36720. doi: 10.7759 / cureus.36720; Metabolic Effects of Ketogenic Diets and Their Utilization in Obesity Management: A Systematic Review

J Nutr Metab. 2020; 2020: 3642035. doi: 10.1155/2020/3642035; Long-Term Ketogenic Diet Induces Metabolic Acidosis, Anemia, and Oxidative Stress in Healthy Wistar Rats

Nutrients. 2023 Dec; 15(23): 4998. doi: 10.3390 / nu15234998 ; The Ketogenic Diet in the Prevention of Migraines in the Elderly

Review Atherosclerosis. 2020 Jan:292:119-126. doi: 10.1016/j.atherosclerosis.2019.11.021.; The ketogenic diet: Pros and cons