Key takeaways

  • The keto diet drastically cuts carbs and replaces them with fat to trigger ketosis.
  • It may help with weight loss and improving markers tied to metabolic disease.
  • Long-term effects are still understudied, so medical guidance is recommended.

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

In fact, many studies show that this type of diet can help you lose weight and improve your health (1).

Ketogenic diets may even have benefits against diabetes, cancer, epilepsy, and Alzheimer’s disease (2, 3, 4, 5).

Read on to learn everything you need to know as a beginner to the keto diet.

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 (6).

Ketogenic diets can cause significant reductions in blood sugar and insulin levels. This, along with the increased ketones, has some health benefits (6, 7, 8).

There are several versions of the ketogenic diet, and what you eat depends on the type. They include:

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.

Ketosis is a metabolic state in which your body uses fat for fuel instead of carbs.

It occurs when you significantly reduce your consumption of carbohydrates, limiting your body’s supply of glucose (sugar), which is the main source of energy for the cells.

Entering ketosis

Following a ketogenic diet is the most effective way to enter ketosis. Generally, this involves limiting carb consumption to around 20 to 50 grams per day and filling up on fats, such as meat, fish, eggs, nuts, and healthy oils (6).

Blood, urine, and breath tests are available, which can help determine whether you’ve entered ketosis by measuring the amount of ketones produced by your body.

Certain symptoms may also indicate that you’ve entered ketosis, including increased thirst, dry mouth, frequent urination, and decreased hunger or appetite (12).

A ketogenic diet is an effective way to lose weight and lower risk factors for disease (1, 2, 3, 4, 5).

In fact, research shows that the ketogenic diet may be as effective for weight loss as a low fat diet (13, 14, 15).

What’s more, the diet is so filling that you can lose weight without counting calories or tracking your food intake (16).

One review of 13 studies found that following a very low carb, ketogenic diet was slightly more effective for long-term weight loss than a low fat diet. People who followed the keto diet lost an average of 2 pounds (0.9 kg) more than the group that followed a low fat diet (13).

What’s more, it also led to reductions in diastolic blood pressure and triglyceride levels (13).

Another study in 34 older adults found that those who followed a ketogenic diet for 8 weeks lost nearly five times as much total body fat as those who followed a low fat diet (17).

The increased ketones, lower blood sugar levels, and improved insulin sensitivity may also play a key role (18, 19).

Diabetes is characterized by changes in metabolism, high blood sugar, and impaired insulin function (20).

The ketogenic diet can help you lose excess fat, which is closely linked to type 2 diabetes, prediabetes, and metabolic syndrome (21, 22, 23, 24).

One older study found that the ketogenic diet improved insulin sensitivity by a whopping 75% (25).

A small study in women with type 2 diabetes also found that following a ketogenic diet for 90 days significantly reduced levels of hemoglobin A1C, which is a measure of long-term blood sugar management (26).

Another study in 349 people with type 2 diabetes found that those who followed a ketogenic diet lost an average of 26.2 pounds (11.9 kg) over a 2-year period. This is an important benefit when considering the link between weight and type 2 diabetes (24, 27).

What’s more, they also experienced improved blood sugar management, and the use of certain blood sugar medications decreased among participants throughout the course of the study (27).

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:

Keep this in mind: Research into many of these areas is far from conclusive.

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

  • Meat: red meat, steak, ham, sausage, bacon, chicken, and turkey
  • Fatty fish: salmon, trout, tuna, and mackerel
  • Eggs: pastured or omega-3 whole eggs
  • Butter and cream: grass-fed butter and heavy cream
  • Cheese: unprocessed cheeses like cheddar, goat, cream, blue, or mozzarella
  • Nuts and seeds: almonds, walnuts, flaxseeds, pumpkin seeds, chia seeds, etc.
  • Healthy oils: extra virgin olive oil, and avocado oil
  • Avocados: whole avocados or freshly made guacamole
  • Low carb veggies: green veggies, tomatoes, onions, peppers, etc.
  • Condiments: salt, pepper, herbs, and spices

It’s best to base your diet mostly on whole, single-ingredient foods.

To help get you started, here are some keto-friendly recipes.

Keep this in mind: Everyone’s nutritional needs are different, and each person should consider their personal health situation when evaluating the recipes suggested in this article.

If you have a health condition or specific nutritional requirements, it’s best to check with a healthcare professional, such as a primary care doctor or registered dietitian, before trying new recipes.

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

.

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

Although getting started on the ketogenic diet can be challenging, there are several tips and tricks that you can use to make it easier.

Many restaurant meals can be made keto-friendly.

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.

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

There’s some anecdotal evidence of these effects often referred to as the keto flu (38). Based on reports from some on the eating plan, it’s usually over within a few days.

Reported keto flu symptoms include diarrhea, constipation, and vomiting (39). Other less common symptoms include:

  • poor energy and mental function
  • increased hunger
  • sleep issues
  • nausea
  • digestive discomfort
  • decreased exercise performance

While the keto diet has its benefits, staying on it in the long term may have some negative effects, including risks of the following:

  • low protein in the blood
  • extra fat in the liver
  • kidney stones
  • micronutrient deficiencies

Safety note: A type of medication called sodium-glucose cotransporter 2 (SGLT2) inhibitors for type 2 diabetes can increase the risk for diabetic ketoacidosis, a dangerous condition that increases blood acidity. Anyone taking this medication should avoid the keto diet (40, 41).

More research is being done to determine the safety of the keto diet in the long term. Keep your doctor informed of your eating plan to guide your choices.

Although no supplements are required, some can be useful.

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

There’s a risk of losing some muscle on any diet. However, protein intake and high ketone levels may help minimize muscle loss, especially if you lift weights (50, 51).

Yes, but it may not work as well as on a moderate carb diet (52, 53).

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.

You may not be in full ketosis or be utilizing fats and ketones efficiently. To counter this, lower your carb intake and revisit the points above. A supplement like MCT oil or ketones may also help (42, 43).

Don’t be alarmed. This is simply due to the excretion of by-products created during ketosis (54).

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

People often confuse ketosis with ketoacidosis. Ketoacidosis is dangerous, but ketosis on a ketogenic diet is usually fine for healthy people. Speak with your doctor before starting any new diet.

This common side effect usually passes after 3 to 4 weeks. If it persists, try eating more high fiber veggies (55, 56).

People often refer to the ketogenic diet colloquially as the keto diet, so these terms refer to the same thing.

In the first week of the keto diet, the weight you lose is typically water weight. Anecdotally, people report losing about 1 lb (0.5 kg) to 10 lb or more (5 kg).

Learn more about weight loss after 1 week on keto.

A ketogenic diet may be good for people who:

  • have a higher body weight
  • have diabetes
  • are 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.

It may also not be sustainable for some people’s lifestyles and preferences. Speak with your doctor about your eating plan and goals to decide if a keto eating plan is right for you.

While following the ketogenic diet, you reduce your carbohydrate intake and replace it with healthy fats. This can help your body to use fat for energy, encouraging weight loss and possibly reducing the chance of developing certain health issues.

That said, consult your doctor prior to engaging in the diet for an extended period of time, as it may have some side effects. More research is needed to understand its long-term effect on the body.