The main idea of the keto diet is to significantly reduce carbohydrate intake and increase fat consumption, which puts the body into a state of ketosis.

However, to achieve and maintain ketosis, it is important to carefully choose food products.

Understanding which foods and in what quantities can be consumed on a keto diet is a key factor for successfully following this nutritional plan and gaining maximum health benefits.

In this article, we will examine the food groups that can and, in some cases, should be eaten on keto. We will also look at the main features of consuming proteins, fats, and carbohydrates in general.

Main Principles of Food Selection

The main focus should be on foods that are low in carbohydrates and high in healthy fats.

On the keto diet, you can consume the following categories of foods in virtually unlimited quantities:

• Meat and Fish: choose fatty cuts of meat (beef, pork, lamb) and fish (salmon, mackerel).
• Vegetables: prefer low-carb, non-starchy vegetables such as broccoli, cabbage, tomatoes, cucumbers, and zucchini.
• Greens: you can consume any greens.
• Dairy Products: any dairy products except milk, low-fat products, and those containing added sugar: cheeses, butter, heavy cream, kefir, and sugar-free yogurts.
• Fats and Oils: olive, coconut, avocado, and flaxseed oils.

In moderate amounts (100-200 grams per day), you can consume:

• Nuts and Seeds: such as almonds, walnuts, chia seeds, and flaxseeds.
• Berries: such as raspberries, strawberries, blueberries, blackberries, and gooseberries.

Protein Sources on the Keto Diet

On the keto diet, it is important to choose not only those protein sources that contain minimal carbohydrates but also those that contain a large amount of fats.

Essentially, the keto diet boils down to one rule – eat those foods that raise insulin levels in the body the least.

Insulin levels are raised by sugar, carbohydrates, and large amounts of protein without fats that restrain it.

Fats help to restrain and reduce the rise in insulin levels. That’s why fatty protein sources are preferred on keto.

When protein is consumed in large quantities without sufficient fat accompaniment, it can partially convert to glucose through the process of gluconeogenesis.

Meat Products: Excellent options include fatty meat, poultry, and fish. For example, beef, chicken, and salmon are not only rich in protein but also contain healthy fats necessary for maintaining ketosis.

Organ meats such as liver, hearts, and gizzards deserve special mention. They contain more nutrients than the meat products themselves.

However, the requirement for fat does not mean that chicken breast or low-fat fish varieties are prohibited on keto.

You can easily include low-fat products in your diet by adding extra fats during cooking. For example, by adding:

• mascarpone and other cheeses;
• homemade mayonnaise or fatty sauces;
• vegetable oils.

Eggs: In addition, eggs are a versatile and accessible source of protein that also contains healthy fats.

Dairy Products: You can also use cheeses and dairy products low in carbohydrates, such as hard cheeses and Greek yogurt.

Nuts and Seeds: Don’t forget about plant sources of protein such as nuts and seeds.

Almonds, walnuts, and chia seeds can be a great addition to dishes, providing not only protein but also healthy fats.

Vegetables and Greens Suitable for Keto

The main principle of counting carbohydrates on the keto diet is to account only for net carbohydrates.

Net Carbohydrates are the total amount of carbohydrates minus probiotics, prebiotics, and sugar alcohols. That is, only those carbohydrates that can affect blood glucose and insulin levels are counted.

Prebiotics serve as food for beneficial bacteria in the intestines. They are not digested or absorbed by the body, and therefore do not affect the number of calories and carbohydrates consumed.

Examples of prebiotics include fiber and inulin.

Probiotics are live microorganisms that help maintain a healthy gut microbiome.

Probiotics themselves do not affect the carbohydrates or calories in your diet.

Sugar Alcohols are a type of low-calorie carbohydrate found in natural products or added to food as sugar substitutes.

They are partially absorbed by the body but have a significantly lesser effect on blood sugar and insulin levels compared to regular sugars.

The best sugar alcohol for keto is erythritol.

Greens: Virtually all greens contain a large amount of fiber and a small amount of other carbohydrates.

Therefore, on keto, it can be consumed in virtually unlimited quantities. You simply cannot eat so much greens that you exceed any carbohydrate limits.

Moreover, greens are not only permissible in large amounts on keto but are also highly recommended.

In general, any greens have anti-inflammatory properties and help to compensate for the effects that a large amount of saturated fats in food can have on the body.

Examples of greens include spinach, arugula, parsley, cilantro, and watercress.

Vegetables: As for vegetables, you can consume any non-starchy vegetables. Virtually all non-starchy vegetables contain a small amount of carbohydrates.

For example, cruciferous vegetables such as broccoli, cauliflower, and regular cabbage are perfect for the keto diet.

Some vegetables, like carrots, pumpkin, or onions, contain more carbohydrates than others, so they should be consumed in moderation.

Like greens, vegetables are highly recommended for consumption on the keto diet due to their anti-inflammatory properties.

Remember that greens and vegetables on keto should be consumed with healthy fats (such as olive oil, homemade mayonnaise, or fatty sauce). This not only helps to restrain insulin spikes but also aids in the absorption of fat-soluble vitamins.

Berries

Since berries contain a large amount of fiber that restrains carbohydrates from fructose, any berries that do not grow on trees are available on keto in moderate amounts.

Cherries, sweet cherries, and mulberries are considered berries, but their consumption is better limited.

100-150 grams of berries are quite permissible for daily consumption.

Berries can be eaten after the main meal as a dessert. This way, there will already be a cushion of fatty food in the stomach that will reduce the possible insulin spike.

Examples of berries include raspberries, blueberries, blackberries, and strawberries.

Fruits on the Keto Diet

Only a small number of fruits are available on the keto diet. But even these fruits are available in small amounts.

For example, you can eat no more than one apple a day.

Fruits contain fructose, which acts similarly to sugar. Moreover, while sugar affects the entire body, fructose strikes the liver specifically. Regularly consuming fruits in large amounts can lead to non-alcoholic fatty liver disease, which can be a cause of liver cirrhosis.

There are exceptions to the fruit limitations: you can eat lemons and limes in large amounts, if you wish.

Coconut is also a fruit. You can consume coconut meat. As for coconut water, it is available in moderate amounts.

The only fruit you can eat in unlimited quantities on keto is the avocado.

Sources of Fats on Keto

In addition to choosing foods high in fats, keto also pays attention to the quality of these fats.

Trans Fats: First and foremost, it is recommended to completely eliminate trans fats, processed fats, and hydrogenated oils from the diet, as they are associated with an increased risk of cardiovascular diseases and inflammatory processes in the body.

Sausages, hot dogs, dumplings, margarine, store-bought mayonnaise, fast food, store-bought baked goods, and any convenience foods generally contain trans fats. They can also be found in products containing hydrogenated oils.

Ideally, you should buy meat and cook it yourself.

Products Containing Omega-6 Fats are necessary for the body. However, high consumption of Omega-6 fat-rich products leads to inflammatory processes in the body due to an imbalance between Omega-3 and Omega-6.

It is therefore recommended to reduce the intake of products rich in Omega-6 or increase the intake of Omega-3 rich products.

Examples of Omega-6 rich foods include sunflower oil, corn oil, and soybean oil.

It is worth noting that Omega-6 fats undergo oxidation and form harmful free radicals during heat treatment. Oxidized fats can cause inflammatory processes in the body.

Monounsaturated Fats: This type of fat is considered healthy, and its consumption is recommended not only on the Mediterranean diet but also on the keto diet.

They help to lower “bad” cholesterol (LDL) and maintain “good” cholesterol (HDL) levels.

Examples of foods rich in monounsaturated fats include olive oil, avocado, and its oil, almonds, and macadamia nuts.

More examples of products containing various types of fats can be found in the additional articles attached below.

Omega-3 Fats are the ideal type of fats for keto, as they have strong anti-inflammatory properties and support brain and heart health.

These fats are abundant in any seafood, including seaweed, shrimp, mussels, and any types of fish (such as salmon, mackerel, and sardines).

From plant sources, flaxseeds, walnuts, chia seeds, and perilla oil are rich in Omega-3.

Saturated Fats on the keto diet are not considered harmful, especially if they come from quality sources such as butter, ghee, coconut oil, and fatty meat.

On the keto diet, saturated fats are used by the body for energy in the process of ketosis, and when consumed in moderation, they can be part of a healthy diet.

Sugar Substitutes

Sugar is completely banned on the keto diet. However, you can replace it with available sugar substitutes that can be consumed in unlimited amounts.

However, it should be noted that consuming any sugar substitutes in large amounts can lead to stomach upset (diarrhea).

Such sweeteners include erythritol, stevia, and monk fruit. These types of sugar substitutes are not absorbed by the body at all.

There are many other sugar substitutes that can be used on keto, such as sucralose and allulose. However, they may affect insulin levels or cause other side effects. Therefore, it is better to avoid or consume other sugar substitutes in small amounts.

What You Can Drink on Keto

But not only food is important for adhering to the keto diet. Even if you perfectly follow the foods listed above, all your efforts can be wasted, for example, due to one glass of juice.

However, there is a wide variety of drinks available on keto, as long as they are free from sugar, honey, and fructose.

Naturally, you can consume any water without restrictions, including mineral, sparkling, sodium, magnesium, and so on.

You also have access to coffee, black and green tea, matcha, mate, hibiscus, herbal teas, and even chicory.

Kombucha is also available on keto in moderate amounts, provided it does not contain added sugar.

The start of a keto diet may be accompanied by unpleasant symptoms known as keto flu.

This condition often causes newcomers to feel fatigued, experience headaches, and become irritable. But there’s no need to panic, as these symptoms are temporary and usually subside within a few days.

In this article, we will discuss the steps that can help you cope with keto flu and continue your journey towards a healthy lifestyle.

Causes of Keto Flu: What Happens in the Body?

Keto flu occurs due to a sharp reduction in carbohydrate intake, leading to changes in metabolism.

When the body begins to use fats instead of carbohydrates as its primary energy source, an adaptation occurs, accompanied by unpleasant symptoms.

Main causes:

Electrolyte imbalance. A decrease in insulin levels leads to a loss of sodium, potassium, and magnesium.

Decreased glycogen levels. When you sharply reduce carbohydrate intake, glycogen stores (the form of glucose storage in the liver and muscles) get depleted quickly.

Glycogen is associated with water, and its loss results in rapid fluid loss.

This can cause dehydration, headaches, and muscle cramps, which are often perceived as symptoms of keto flu.

Decreased insulin levels. With reduced carbohydrate intake, insulin production decreases.

While this is a desired effect of the keto diet, a sharp drop in insulin leads to increased sodium and water loss through the kidneys, which can cause electrolyte imbalance.

This further exacerbates keto flu symptoms such as dizziness and weakness.

Decreased serotonin levels. Carbohydrates are involved in synthesizing serotonin, the “happiness hormone.”

A sharp decrease in carbohydrates may lower serotonin levels, potentially leading to temporary mood deterioration or even depression.

Hormonal changes. Adapting to new energy metabolism conditions can cause temporary hormonal disruptions.

Decreased availability of quick energy sources. Carbohydrates are a simpler source of energy than fats. When the body transitions to using fats as fuel, it takes time to enter a state of ketosis.

During this period, cells experience an energy deficit, which can cause fatigue, slow reaction times, and decreased endurance.

At the beginning of the keto diet, ketone levels (alternative energy sources) are not yet stable. The body does not immediately produce enough ketones, leading to insufficient energy supply for tissues.

Maintaining Water and Electrolyte Balance

Electrolytes play a crucial role in cellular energy production (ATP).

Without sufficient sodium, potassium, and magnesium, cells may struggle to produce energy, leading to feelings of fatigue.

Maintaining water and electrolyte balance is a key aspect of overcoming keto flu.

When transitioning to a keto diet, the body loses more water and electrolytes, which can cause unpleasant symptoms.

To avoid this, include in your diet:

• Salt supplements: use Himalayan or sea salt to restore sodium;
• Magnesium-rich foods, such as avocados, nuts, and seeds;
• Potassium-rich foods, such as avocados, parsley, spinach, and other greens;
• Drink bone broth to replenish electrolytes.

Also, remember to drink enough water to avoid dehydration.

This will significantly help reduce the symptoms of keto flu and alleviate fatigue and headaches.

Physical Activity

Physical activity plays a key role in helping the body adapt to the keto diet and minimizing the symptoms of keto flu.

During keto flu, it is important to choose moderate exercises such as walking, yoga, or light cardio workouts.

This will help maintain energy levels and improve circulation.

During keto flu, the body may lack energy, so heavy workouts can worsen well-being and increase fatigue.

Once the body adapts to the new energy source, you can gradually increase the intensity of workouts. Strength training and intense cardio workouts will become more effective as the body becomes better at using fats as fuel.

Moderate activity, on the other hand, helps reduce stress levels and improve overall well-being.

Additionally, physical activity promotes the activation of fat metabolism, which is important for speeding up the adaptation process to using fats as the primary energy source.

Rest

During the adaptation period to the keto diet, the body requires time to recover and transition into ketosis.

Sleep plays a key role here, as the body restores its strength, reduces stress levels, and regulates hormonal processes during sleep.

Lack of sleep can increase cortisol levels (the stress hormone), which can exacerbate the symptoms of keto flu.

High cortisol levels can hinder the transition into ketosis and worsen unpleasant symptoms such as irritability and anxiety.

Try to sleep at least 7-8 hours a day and avoid stressful situations.

Relaxation and meditation can help improve sleep quality and lower cortisol levels, positively impacting your well-being.

Supplements

Supplements can significantly alleviate the symptoms of keto flu and speed up the body’s adaptation to ketosis.

Here are some key supplements to consider.

Electrolytes. Since the body loses more water and electrolytes on a keto diet due to reduced insulin levels, replenishing sodium, potassium, magnesium, and calcium becomes important.

Special electrolyte mixes or supplements with sodium and potassium can help maintain normal water-salt balance, prevent dehydration, cramps, and fatigue.

Magnesium. Magnesium plays a key role in muscle function, the nervous system, and energy metabolism. Many experience a deficiency of it on a keto diet, which can cause muscle cramps and weakness.

Magnesium supplements (e.g., magnesium citrate, magnesium glycinate) can help relieve cramps, improve sleep, and reduce fatigue.

Potassium. Potassium helps regulate blood pressure, muscle function, and supports the cardiovascular system. A deficiency of potassium can cause weakness, fatigue, and cramps.

Potassium supplements, such as potassium tartrate, can prevent deficiency.

Sodium. Sodium is lost through sweating and frequent urination. A sodium deficiency can lead to headaches, weakness, and dizziness.

Adding more salt than usual to food or taking salt solutions can help replenish sodium losses.

Omega-3. Omega-3 fatty acids help reduce inflammation, support heart and brain health.

On a keto diet, this can be especially important for reducing overall inflammation and maintaining energy levels.

Vitamin D. It is important to maintain vitamin D levels on a keto diet, as it helps with calcium absorption and supports bone and immune system health.

This is especially relevant for people who do not get enough sunlight.

MCT oil. MCTs (medium-chain triglycerides) can help speed up the ketosis process and provide a quick source of energy.

MCT acids are quickly converted into ketones and can be useful for maintaining energy in the early stages of the keto diet.

For many people following a keto diet, the question of how alcohol fits into this lifestyle becomes quite relevant.

While some alcoholic beverages may be permissible, others can lead to significant deviations from the dietary plan.

It’s important to understand which alcoholic drinks contain minimal amounts of carbohydrates and how their consumption can affect your body.

Alcohol and Carbohydrates: What You Need to Know?

When it comes to alcohol and the keto diet, it’s important to understand that not all alcoholic beverages are created equal in terms of carbohydrate content. Some types of alcohol contain significant amounts of carbohydrates, which can lead to being kicked out of ketosis.

First and foremost, it’s important to avoid sweet cocktails and liqueurs, as they often contain added sugars and syrups.

For example, popular cocktails like margaritas or piña coladas can contain over 20 grams of carbohydrates per serving.

Beer, especially light beer, can also be a source of hidden carbohydrates. It contains between 10 to 20 grams of carbohydrates per bottle.

Wine and strong alcoholic beverages, such as vodka, whiskey, and rum, are more suitable options for the keto diet.

However, even among wines, there are differences: dry wines contain fewer carbohydrates compared to sweet wines or dessert wines.

For example, dry white wine typically contains about 2-3 grams of carbohydrates per glass, while sweet dessert wine can contain up to 14 grams of carbohydrates per serving.

Thus, when choosing alcoholic beverages on a keto diet, it’s important to read labels carefully and prefer drinks with minimal carbohydrate content to avoid disrupting ketosis.

Allowed Alcoholic Beverages on the Keto Diet

Some types of alcohol can fit into your diet if chosen wisely.

Dry wines are one of the best options. In red and white dry wines, sugar content is minimal, making them suitable for the keto diet.

For example, wines like Cabernet Sauvignon, Merlot, and Chardonnay contain about 3-4 grams of carbohydrates per glass.

Another great choice is spirits with low carbohydrate content. These include vodka, gin, rum, tequila, and whiskey.

These drinks contain virtually no carbohydrates, but it’s important to avoid sweet cocktails and liqueurs, which can be high in sugar.

You can also look for low-carb cocktails. For instance, vodka with soda and lime or gin with sugar-free tonic are tasty and safe options for the keto diet.

Don’t forget to check the ingredients and avoid adding sweet juices and syrups.

Tips for Consumption

Here are some tips for consuming alcohol on a keto diet:

1. Practice moderation: Alcohol can slow down the ketosis process and increase insulin levels. Try to limit your consumption of alcoholic beverages.
2. Stay hydrated: Alcohol can cause dehydration, so drink enough water to avoid unpleasant symptoms.
3. Avoid sweet cocktails: Cocktails made with fruit juices, syrups, and soda can be high in sugar and carbohydrates.

The Impact of Alcohol on Ketosis and Metabolism

Alcohol can have a significant impact on ketosis and metabolism.

Consuming alcohol slows down metabolic processes as the body prioritizes ethanol as an energy source. This can temporarily reduce or even interrupt ketosis, as the liver redirects its resources to process alcohol instead of producing ketones.

Alcohol can also affect appetite and food intake. Drinking alcohol often leads to a decrease in food control, which can result in consuming large amounts of carbohydrates and disrupting ketosis.

Therefore, if you are following a keto diet, it is advisable to avoid alcohol altogether if possible.

The keto diet is traditionally associated with a high intake of meat and animal products. Therefore, vegetarians and vegans seeking to follow this dietary regime may face unique challenges.

However, by understanding the basic principles of the keto diet, it is quite possible to adapt it to a vegetarian or vegan lifestyle.

This approach requires careful selection of foods to ensure the body receives all the necessary nutrients while avoiding high-carbohydrate foods.

Basic Principles of the Keto Diet for Vegetarians and Vegans

The keto diet for vegetarians and vegans requires a special approach to ensure adequate intake of proteins and fats while avoiding carbohydrates.

The main principle involves replacing animal products with plant-based alternatives that are rich in fats and proteins. For example, important sources of fats can include:

• avocado;
• nuts;
• seeds;
• coconut and olive oil.

An important aspect is the choice of protein sources. Vegans can rely on:

• nuts;
• seeds;
• soy products;
• plant-based protein powders.

Vegetarians can additionally use products such as:

• tofu;
• tempeh;
• dairy products, if they are not excluded from the diet.

For example, almonds, chia seeds, and hemp seeds are rich in protein and healthy fats.

It is important to monitor carbohydrate intake to keep it under 20-50 grams per day.

Foods to Avoid

On the keto diet, it is important to avoid foods that are high in carbohydrates to maintain a state of ketosis.

First of all, eliminate grains and grain products from your diet, such as bread, pasta, rice, and oatmeal, as they contain significant amounts of carbohydrates.

Most legumes, including beans, lentils, and peas, should also be avoided, as they are also high in carbohydrates.

Sweet fruits, such as bananas, apples, and grapes, should also be limited, as they contain a lot of sugar.

Tips and Recommendations

For successfully following the keto diet, it is important for vegetarians and vegans to carefully plan their meals to avoid nutrient deficiencies.

Do not forget to include a variety of vegetables in your diet, such as spinach, broccoli, and cauliflower. They are not only low in carbohydrates but also rich in vitamins and minerals.

Use the aforementioned sources of healthy fats and protein. You can also add:

• coconut products;
• flaxseeds for making bread;
• seaweed and supplements based on them;
• nut-based cheeses;
• any keto sweeteners;
• berries;
• olives.

Drink plenty of water and take supplements like vitamins B12 and D to maintain overall health.