The ketogenic diet (or keto diet, for short) is a low-carb, high-fat diet that offers many health benefits.

In fact, over 20 studies show that this type of diet can help you lose weight and improve your health ().

Ketogenic diets may even have benefits against diabetes, cancer, epilepsy and Alzheimer's disease (, , , ).

Here is a detailed beginner's guide to the keto diet.

What Is a Ketogenic Diet?

Ketogenic Diet 101

The ketogenic diet is a very low-carb, high-fat diet that shares many similarities with the Atkins and low-carb diets.

It involves drastically reducing carbohydrate intake and replacing it with fat. This reduction in carbs puts your body into a metabolic state called ketosis.

When this happens, your body becomes incredibly efficient at burning fat for energy. It also turns fat into ketones in the liver, which can supply energy for the brain (, ).

Ketogenic diets can cause massive reductions in blood sugar and insulin levels. This, along with the increased ketones, has numerous health benefits (, , , , ).

Summary The keto diet is a low-carb, high-fat diet. It lowers blood sugar and insulin levels, and shifts the body’s metabolism away from carbs and towards fat and ketones.

Different Types of Ketogenic Diets

There are several versions of the ketogenic diet, including:

However, only the standard and high-protein ketogenic diets have been studied extensively. Cyclical or targeted ketogenic diets are more advanced methods and primarily used by bodybuilders or athletes.

The information in this article mostly applies to the standard ketogenic diet (SKD), although many of the same principles also apply to the other versions.

Summary There are several versions of the keto diet. The standard (SKD) version is the most researched and most recommended.

Ketogenic Diets Can Help You Lose Weight

A ketogenic diet is an effective way to lose weight and lower risk factors for disease (, , , , , ).

In fact, research shows that the ketogenic diet is far superior to the often recommended low-fat diet (, , , ).

What's more, the diet is so filling that you can lose weight without counting calories or tracking your food intake ().

One study found that people on a ketogenic diet lost 2.2 times more weight than those on a calorie-restricted low-fat diet. Triglyceride and HDL cholesterol levels also improved ().

Another study found that people on the ketogenic diet lost 3 times more weight than those on the diet recommended by Diabetes UK ().

There are several reasons why a ketogenic diet is superior to a low-fat diet, including the increased protein intake, which provides numerous benefits (, , ).

The increased ketones, lower blood sugar levels and improved insulin sensitivity may also play a key role (, , , , , ).

For more details on the weight loss effects of a ketogenic diet, read this article.

Summary A ketogenic diet can help you lose much more weight than a low-fat diet. This often happens without hunger.

Ketogenic Diets for Diabetes and Prediabetes

Diabetes is characterized by changes in metabolism, high blood sugar and impaired insulin function (27).

The ketogenic diet can help you lose excess fat, which is closely linked to type 2 diabetes, prediabetes and metabolic syndrome (, , ).

One study found that the ketogenic diet improved insulin sensitivity by a whopping 75% ().

Another study in people with type 2 diabetes found that 7 of the 21 participants were able to stop using all diabetes medications ().

In yet another study, the ketogenic group lost 24.4 pounds (11.1 kg), compared to 15.2 pounds (6.9 kg) in the higher-carb group. This is an important benefit when considering the link between weight and type 2 diabetes (, ).

Additionally, 95.2% of the ketogenic group were also able to stop or reduce diabetes medication, compared to 62% in the higher-carb group ().

For more information, check out this article on the benefits of low-carb diets for people with diabetes.

Summary The ketogenic diet can boost insulin sensitivity and cause fat loss, leading to significant health benefits for people with type 2 diabetes or prediabetes.

Other Health Benefits of Keto

The ketogenic diet actually originated as a tool for treating neurological diseases such as epilepsy.

Studies have now shown that the diet can have benefits for a wide variety of different health conditions:

However, keep in mind that research into many of these areas is far from conclusive.

Summary A ketogenic diet may provide many health benefits, especially with metabolic, neurological or insulin-related diseases.

Foods to Avoid

Any food that is high in carbs should be limited.

Here is a list of foods that need to be reduced or eliminated on a ketogenic diet:

Summary Avoid carb-based foods like grains, sugars, legumes, rice, potatoes, candy, juice and even most fruits.

Foods to Eat

You should base the majority of your meals around these foods:

It is best to base your diet mostly on whole, single-ingredient foods. Here is a list of 44 healthy low-carb foods.

Summary Base the majority of your diet on foods such as meat, fish, eggs, butter, nuts, healthy oils, avocados and plenty of low-carb veggies.

A Sample Keto Meal Plan For 1 Week

To help get you started, here is a sample ketogenic diet meal plan for one week:

Monday

Tuesday

Wednesday

Thursday

Friday

Saturday

Sunday

Always try to rotate the vegetables and meat over the long term, as each type provides different nutrients and health benefits.

For tons of recipes, check out these 101 healthy low-carb recipes.

Summary You can eat a wide variety of tasty and nutritious meals on a ketogenic diet.

Healthy Keto Snacks

In case you get hungry between meals, here are some healthy, keto-approved snacks:

Summary Great snacks for a keto diet include pieces of meat, cheese, olives, boiled eggs, nuts and dark chocolate.

Tips for Eating Out on a Ketogenic Diet

It is not very hard to make most restaurant meals keto-friendly when eating out.

Most restaurants offer some kind of meat or fish-based dish. Order this, and replace any high-carb food with extra vegetables.

Egg-based meals are also a great option, such as an omelet or eggs and bacon.

Another favorite is bun-less burgers. You could also swap the fries for vegetables instead. Add extra avocado, cheese, bacon or eggs.

At Mexican restaurants, you can enjoy any type of meat with extra cheese, guacamole, salsa and sour cream.

For dessert, ask for a mixed cheese board or berries with cream.

Summary When eating out, select a meat-, fish- or egg-based dish. Order extra veggies instead of carbs or starches, and have cheese for dessert.

Side Effects and How to Minimize Them

Although the ketogenic diet is safe for healthy people, there may be some initial side effects while your body adapts.

This is often referred to as the keto flu and is usually over within a few days.

Keto flu includes poor energy and mental function, increased hunger, sleep issues, nausea, digestive discomfort and decreased exercise performance.

To minimize this, you can try a regular low-carb diet for the first few weeks. This may teach your body to burn more fat before you completely eliminate carbs.

A ketogenic diet can also change the water and mineral balance of your body, so adding extra salt to your meals or taking mineral supplements can help.

For minerals, try taking 3,000–4,000 mg of sodium, 1,000 mg of potassium and 300 mg of magnesium per day to minimize side effects.

At least in the beginning, it is important to eat until you’re full and avoid restricting calories too much. Usually, a ketogenic diet causes weight loss without intentional calorie restriction.

Summary Many of the side effects of starting a ketogenic diet can be limited. Easing into the diet and taking mineral supplements can help.

Supplements for a Ketogenic Diet

Although no supplements are required, some can be useful.

Summary Certain supplements can be beneficial on a ketogenic diet. These include exogenous ketones, MCT oil and minerals.

Frequently Asked Questions

Here are answers to some of the most common questions about the ketogenic diet.

1. Can I ever eat carbs again?

Yes. However, it is important to significantly reduce your carb intake initially. After the first 2–3 months, you can eat carbs on special occasions — just return to the diet immediately after.

2. Will I lose muscle?

There is a risk of losing some muscle on any diet. However, the high protein intake and high ketone levels may help minimize muscle loss, especially if you lift weights.

3. Can I build muscle on a ketogenic diet?

Yes, but it may not work as well as on a moderate-carb diet. For more details about low-carb or keto diets and exercise performance, read this article.

4. Do I need to refeed or carb load?

No. However, a few higher-calorie days may be beneficial every now and then.

5. How much protein can I eat?

Protein should be moderate, as a very high intake can spike insulin levels and lower ketones. Around 35% of total calorie intake is probably the upper limit.

6. What if I am constantly tired, weak or fatigued?

You may not be in full ketosis or be utilizing fats and ketones efficiently. To counter this, lower your carb intake and re-visit the points above. A supplement like MCT oil or ketones may also help.

7. My urine smells fruity. Why is this?

Don't be alarmed. This is simply due to the excretion of by-products created during ketosis.

8. My breath smells. What can I do?

This is a common side effect. Try drinking naturally flavored water or chewing sugar-free gum.

9. I heard ketosis was extremely dangerous. Is this true?

People often confuse ketosis with ketoacidosis. The former is natural, while the latter only occurs in uncontrolled diabetes.

Ketoacidosis is dangerous, but the ketosis on a ketogenic diet is perfectly normal and healthy.

10. I have digestion issues and diarrhea. What can I do?

This common side effect usually passes after 3–4 weeks. If it persists, try eating more high-fiber veggies. Magnesium supplements can also help with constipation.

A Ketogenic Diet Is Great, but Not for Everyone

A ketogenic diet can be great for people who are overweight, diabetic or looking to improve their metabolic health.

It may be less suitable for elite athletes or those wishing to add large amounts of muscle or weight.

And, as with any diet, it will only work if you are consistent and stick with it in the long term.

That being said, few things are as well proven in nutrition as the powerful health and weight loss benefits of a ketogenic diet.

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