The ketogenic (keto) diet is a low-carb, moderate-protein, and high-fat diet. On this diet, around 70% of your calories should come from fat, 25% from protein, and 5% from carbohydrates. Eating this way puts your body in ketosis – the primary goal of the keto diet from which it got its name. The second goal of keto is keto-adaptation.
People follow the keto diet because of its many science-backed benefits, one of the most prominent of which is weight loss. Research shows that people lose more weight after 3 months on the keto diet than on a low-fat diet . Other keto diet benefits include prevention and treatment of cardiovascular diseases, type 2 diabetes, epilepsy, cancer, liver disease, and neurological conditions .
The ketogenic diet is a very low-carb diet (VLCD) similar to Atkins. It has been growing in popularity in the last couple of years mostly as a weight-loss diet; however, keto has been around for much longer and was not originally conceived as a weight-loss diet.
The history of the keto diet actually starts in the 1920s when researchers introduced it as an epilepsy treatment . They noticed that reducing carbs leads to the same metabolic benefits of fasting, an age-long epilepsy cure.
The most prominent of these metabolic benefits is lower blood glucose and ketogenesis. Ketogenesis is the production of ketones, three acidic molecules that serve as a fuel alternative to glucose:
Once ketones reach certain levels in the blood, you are in a metabolic state called ketosis. The ketogenic diet helps you reach ketosis by almost eliminating the main source of blood glucose – carbohydrates. The diet also allows for lots of fat and adequate protein.
When talking about the keto diet, what most people are referring to is a "standard" one-size-fits-all approach. Typically, the standard keto diet involves the following macros ratio:
Besides the above ratios, eating 20-50g of carbs a day is part of the standard approach to keto. This approach works best if you're eating 2,000-2,500 calories per day, are moderately active, and are in relatively good health. However, if you have special nutrition requirements, then you may want to consider other keto diet types:
The TKD is your best option if you're an athlete or a gym-goer. This version involves consuming carbs around workouts, either immediately before or immediately after. Carb limits should still be low, though ( 20-50g per day). The goal of the TKD is to fuel your workouts and replenish muscle glycogen for quick recovery while still helping you stay in ketosis.
The CKD is another athlete-friendly keto diet. Professional athletes find that they need a carb boost to really power through their training. On a CKD, you would follow a standard keto diet for 5 days and carb up for two days during training or two days prior to a competition. This approach helps restore muscle glycogen but also build muscle .
The MAD restricts carbohydrates to 10 g/day in kids and 15 g/day in adults. It was originally developed as a less restrictive ketogenic diet for children with epilepsy. With MAD, there is no fluid or calorie restriction and fats are not measured. What makes it different from a standard keto diet is that it allows more protein (35% of the daily calorie intake).
There are many more versions of the keto diet such as the Restricted Ketogenic Diet (RKD) often used as adjuvant therapy for brain cancer management or MCT keto diet that helps suppress hunger and food cravings.
The keto diet provides physical, mental, and disease-modifying benefits. All these benefits were carefully studies over the past century, and the evidence is pretty convincing:
On this diet, 97% of the weight lost is body fat, while muscle mass is preserved or even enhanced. The diet works by upregulating fat oxidation. However, it also works because, in order to sustain ketosis, the body uses up extra calories. One of the most energy expensive metabolic pathways upregulated for ketosis is gluconeogenesis.
Gluconeogenesis involves converting non-carbohydrate substrates (like protein) into glucose. The energy costs of this process have been calculated at 400-600 kcal/day . So, even if you don't count your calories, you'll be losing weight.
Ketones yield more energy than carbs . You'll definitely feel the power of ketones once you're in ketosis as increased physical energy. But there's another reason you'll feel almost as if you have the boundless energy of your youth: no more sugar crashes.
Sugar burns quickly, leaving you high and dry come noon. So, if you suffer from midday slumps, then blame it on low glucose levels from inefficient carby breakfasts. The keto diet eliminates daily energy fluctuations because it lets your body tap into an almost unlimited fuel supply – fatty food and body fat.
Athletes are often told that carbs are key to good performance and body composition. And while this is true to some extent, that's not the whole story. Recent studies found that fat-adapted athletes experienced enhanced fat oxidation during workouts, optimal performance, and improved body composition .
Most studies that found keto to be detrimental to exercise performance were short-term . In other words, to get the exercise benefits of keto, you need to be on this diet for at least 6-8 weeks or longer. This will give your body enough time to become truly fat-adapted.
A razor-sharp mind is one of the most appreciated benefits of being in ketosis. As already stated, ketones are a more efficient fuel than glucose, and this is especially true in regard to the brain. In fact, your brain uses most of the ketones produced during ketosis .
Another reason your mind will be more focused on a keto diet is that ketones improve mitochondrial functioning . Mitochondria are the powerhouses of (brain) cells, and their health and functioning determine how well your body makes energy.
Many mood disorders result from abnormalities within the brain. The ketogenic diet has a strong effect on many targets involved in the onset of mood disorders, including glutamate/GABA transmission, monoamine levels, mitochondrial function, neuron growth, oxidative stress, insulin dysfunction, and inflammation. .
The keto diet also helps reduce stress levels and improves sleep quality, which is important when tackling mood disorders. And besides mood disorders, keto is also promising for ADHD, anxiety, schizophrenia, and autism .
The keto diet is a great treatment for diabetes. For example, a study involving 49 participants with type 2 diabetes found that those on a keto diet showed greater improvement in A1c and most were able to completely stop taking their diabetes medication .
Non-alcoholic Fatty Liver Disease (NAFLD) is fairly common in the Western world. It's caused by excess intake of refined carbohydrates, diabetes, and metabolic syndrome. These conditions lead to a buildup of fat in the liver, putting those affected at risk of cirrhosis and cancer. A large systematic review concluded that this diet leads to significant reduction in NAFLD .
Despite being a diet very high in fat, studies show keto is good for heart health . Keto reduces risk factors for cardiovascular/heart disease like diabetes, high blood glucose, elevated insulin, inflammation, and excess body fat.
And when it comes to the diet's effects on blood lipids specifically, keto shows good results there too. The diet increases both good HDL and so-called bad LDL cholesterol while lowering triglyceride levels . However, the diet also increases LDL particle sizes, which also reduces CVD risk.
If you're ready to start keto, then there are necessary steps you need to take to avoid falling flat on your face. These steps will ensure you enter ketosis safely and stay there to experience keto diet benefits.
Empty your fridge and pantry of high-carb foods and replace it with ketogenic foods like olive oil, butter, minced meat, nuts, and seeds. That way, you'll avoid getting tempted and stay consistent with your diet. To learn how to make a foolproof keto diet plan, read this quick guide.
The keto flu is a common but completely avoidable side effect of the keto diet. It happens as a result of dwindling blood glucose levels and electrolyte imbalances. Replenishing your electrolytes and keeping track of your macros can help you avoid and treat the keto flu.
Ketone strips can help you know if you're on the right track. You can also test for ketosis by looking at ketosis signs and symptoms.
Keto beginners need to keep track of their macros. Using a keto calculator an apps such as MyFitnessPal help a lot with this. Definitely download this on your phone before starting your diet.
MCT oil contains medium-chain triglycerides. These fats are scientifically proven to boost weight loss on a keto diet . They're also highly satiating and ketogenic. Making them a part of your keto diet will help you enter ketosis quicker, keep you feeling full, and they're also a central ingredient of keto coffee.
To avoid diet mishaps, it's good to know what is and what isn’t allowed on keto. The keto diet is strict about many things, including what you should and shouldn't do. Follow these guidelines to make your diet a success.
Since you'll be eating lots of fat on keto, it's a good idea to go for the healthy fats. Examples of healthy fats are monounsaturated fats (MUFAs), some polyunsaturated fats (PUFAs) like omega-3s, and saturated fats. Good sources of these fats include nuts, seeds, fatty fish, butter, coconut oil, and other real foods.
Loss of glycogen in the first week on this diet leads to rapid fluid loss as well as electrolyte imbalances. Both can leave you feeling dehydrated, tired, achy, and generally miserable. To prevent this, drink up to 8 glasses of electrolyte-enriched water a day or replenish your fluids with liquid meals.
Low-carb vegetables are valuable sources of vitamin, minerals, and fiber. You need to eat these on a keto diet to avoid nutrient deficiencies and to maintain gut health. You'll also want to eat small amounts of low-carb fruit to stay healthy on keto.
If you plan to take on keto to manage a health condition, you need to speak to your doctor first. If, for example, you want to treat type 2 diabetes with keto, your doctor should help adjust your insulin dose to help you avoid hypoglycemia and ketoacidosis.
Exercising is not necessary to lose weight on keto. However, it does speed up the process, helps you build muscle, and boosts your health and well-being. Moderate aerobic activity is good at any time during your keto journey.
Trans fats are extremely unhealthy, with studies linking them to CVD, cancer, diabetes, and obesity . They're most abundant in partially hydrogenated vegetable oil and some margarines. You may also want to avoid refined vegetable oils as these lead to inflammation.
There's a good reason why keto limits protein intake to 0.8-1g per kg of body weight: too much protein can kick you out of ketosis via gluconeogenesis. However, if you keep your protein intake moderate, your body will use it to build and repair tissue, make hormones, and maintain your body's pH.
You can exercise all you want when you're keto-adapted. However, during keto induction, vigorous workouts can damage the muscles. That's because your muscles are still not efficient at utilizing fat for fuel and they are also depleted of glycogen early in your keto journey.
The keto diet is not forgiving of cheat meals. Even one cheat meal will kick you out of ketosis. However, if you plan to follow a CKD, then that's a different story. But, as already said, the CKD is best suitable for highly-active people who use up the excess carbs during their workouts and to build muscle.
In case you're curious to know how the keto diet looks like in practice, read this article about what to eat on a keto diet. And also check out this brief sample of keto diet meals:
Two eggs scrambled with a generous pat of butter and seasoned with a bit of salt and pepper.
Calories: 327 kcal, Fat: 31g, Protein: 11g, Net carbs: 1g
Keto chicken soup with shredded chicken, mushrooms, carrots, and green cabbage.
Calories: 500 kcal, Fat: 40g, Protein: 33g, Net carbs: 4g
Asian stir-fry with cabbage and ground beef fried in butter and sprinkled with sesame oil.
Calories: 1023 kcal, Fat: 93g, Protein: 33g, Net carbs: 10g
The keto diet is safe for the most part. However, it does come with its fair share of side effects and risks. Knowing what the hazards of going keto are will help you stay safe and be prepared if you notice any issues.
The keto flu is not really a flu, but a combination of symptoms that people experience when they first start the keto diet. It is the result of hypoglycemia combined with electrolyte imbalances. To fight and prevent the keto flu, drink plenty of fluids, take electrolytes, rest, and eat enough fat. Also consider exogenous ketones as these help ease ketosis transitioning.
For people with diabetes and even healthy folk, the keto diet can cause hypoglycemia. To prevent hypoglycemia, it is important to lower your insulin dose if you have diabetes or reduce your carbs slowly if you're healthy but notice hypoglycemia symptoms early in your keto diet.
Keto rash is a less common side effect of the keto diet. It's an itchy rash around the chest area and the causes of which remain unknown. A possible explanation for keto rash is that ketones, which are acidic in nature, exit through the sweat glands and irritate the skin. Researchers noticed that the rash is common with ketosis . Whatever its cause, keto rash usually resolves on its own and is not dangerous.
Keto breath is one of the most embarrassing ketosis side effects. It's caused by acetone being released through the lungs. Luckily, this fruity smelling breath goes away once you become keto-adapted, which is when your body utilizes ketones more effectively so fewer end up being expelled through urine and breath.
The ketogenic diet is a type of low-carb diet different from Atkins and is linked to a plethora of health outcomes. However, the most sought-after health benefit of keto is weight loss. Research shows keto helps people melt fat while keeping hunger under control.
On keto, you need to eat less than 50g carb a day and replace high-carb food with fats. This can be tricky since most people are used to eating carb-based meals. However, with a bit of time and practice, anyone can go keto.
Besides food, the keto diet also involves tracking macros, measuring ketosis, and exercising. However, this is purely optional. The diet works alone with no need to include exercising. And many people develop a feel for this diet, which makes tracking food intake unnecessary.