The keto diet is known as a low-carb diet where the body produces ketones in the liver to be used as energy. It is called by many different names - ketogenic diet, low-carb diet, low carb high fat (LCHF), etc. When you eat something that is high in carbohydrates, your body produces glucose and insulin.
Glucose is the molecule that your body can most easily convert and use as energy, making it preferred over any other energy source.
Insulin is produced to process the glucose in your bloodstream by transporting it throughout your body.
Since the glucose is used as primary energy, your fats are not needed and are therefore stored. Normally, on a normal, high-carbohydrate diet, the body uses glucose as its main form of energy. By reducing carbohydrate intake, the body is put into a state called ketosis.
Ketosis is a natural process the body initiates to survive when food intake is low. In this state, we produce ketones, which are created when fats are broken down in the liver. The goal of a properly done keto diet is to get the body into this metabolic state. This is not done by starving calories, but by starving carbs. Our bodies are incredibly adaptable to what you feed them - if you overload them with fats and take away carbs, they will start burning ketones as their primary energy source.

As we said, ketosis is a "metabolic state that occurs when you eat a very low-carb, moderate-protein, high-fat diet (or fast for extended periods of time) that causes your body to switch from using glucose as its primary fuel source to using ketones. Ketones themselves are produced when the body burns fat, and they are used primarily as an alternate fuel source when glucose is unavailable." In other words, you go from being a sugar burner to a fat burner. However, we would like to point out that a low-carb diet alone is often not enough to achieve ketosis.
The ketogenic diet offers the following advantages:

Weight loss is probably the most commonly cited health benefit of the ketogenic diet, and it's impossible to ignore. With the keto diet, weight loss is real and effective for one simple reason: it helps people switch from a high-carb, carb-burning diet to a high-fat, fat-burning diet. A high-carb diet leads to bloating, weight gain, and poor health and relies on carbohydrates for energy. A high-fat, low-protein, very low-carb diet curbs appetite, lets you eat until you're full, and burns the fat in your body and in your food as energy.

Whether you're fit, a little out of shape, or obese, a ketogenic diet can not only help you reach or maintain your goal weight, but also reduce your risk factors for obesity-related diseases and disorders, such as diabetes, heart disease, stroke, and certain cancers.

And the best part? You don't have to starve yourself to achieve this goal. A keto diet allows you to eat your fill of filling foods rich in good fats, which triggers a fat-burning metabolic process called ketosis. Once your body gets used to it, it leads to increased energy and physical activity.

There is evidence that ketogenic diets can help with weight loss.

It can help you lose fat, maintain muscle mass, and improve many disease markers ( 9 , 10 , 11 , 12 ).

Some studies suggest that a ketogenic diet may be more effective for weight loss than a low-fat diet, even when total calorie intake remains the same ( 11 ).

In an older study, participants on a ketogenic diet lost 2.2 times more weight than those on a low-calorie, low-fat diet. Triglyceride and HDL (good) cholesterol levels also improved ( 13 ).

However, both groups reduced calorie consumption to a comparable extent, which may have further enhanced weight loss ( 13 ).

Another study from 2007 compared a low-carbohydrate diet with the Diabetes UK dietary guidelines and found that the low-carbohydrate group lost 15.2 pounds (6.9 kg), while the low-fat group lost only 4.6 pounds (2.1 kg). Over a 3-month period, the low-carbohydrate diet resulted in three times as much weight loss ( 14 ).

However, there was no difference in HbA1c, ketone or lipid levels between the groups. Additionally, participants on the low-carb diet also reduced their calorie intake. Finally, there was no difference in fat or protein intake between the two groups. This is important to know when people increase their fat intake because they are following a keto diet.

However, there are conflicting theories about these results. Some researchers argue that the results are simply due to higher protein intake, while others believe that the ketogenic diet provides a distinct "metabolic advantage" ( 15 , 16 ).

Other studies on the ketogenic diet have found that the ketogenic diet can lead to a reduction in appetite and food intake, which is extremely important when translating the research findings into practice (17, 18).

If you don't feel like counting calories, a ketogenic diet might be a good option for you. You can leave out certain foods and don't have to track calories.

The ketogenic diet still requires you to check labels and keep an eye on the total amount of carbohydrates per day, which requires careful food selection.

However, keep in mind that many of the studies mentioned above included only small samples and only examined the short-term effects of the diet.

Further research is needed to determine how the diet affects weight loss in the long term and whether weight gain returns once normal eating is resumed.

Inflammation is the body's natural immune response to heal and fight infection. However, excessive and prolonged inflammation can cause unpleasant symptoms such as pain, joint stiffness, swelling, fatigue and acute physiological consequences.

When you follow a keto diet and are regularly in a state of ketosis, your body produces ketones, specifically BHB (ß-hydroxybutyrate), a powerful anti-inflammatory substance. BHB helps inhibit the inflammatory pathways (NF-kB and COX-2) and also activates the AMPK (AMP-activated protein kinase) pathway, which helps inhibit the NF-kB inflammatory pathways. In addition, BHB has been shown to have similar effects to pain-relieving drugs such as NSAIDs by inhibiting the enzyme COX-2.
Another anti-inflammatory influence is the ketogenic diet itself; the keto diet promotes the consumption of anti-inflammatory foods such as eggs, olive oil, coconut oil, avocados and other foods high in omega-3, all of which are known for their anti-inflammatory effects. The diet plan also promotes the avoidance of inflammatory foods. Not sure what these are? Check out the lists below for some popular anti-inflammatory and pro-inflammatory foods.

#Anti-inflammatory foods
eggs
olive oil
coconut oil
avocados
fatty fish
spinach
cauliflower
broccoli
blueberries
bone broth
Garlic
nuts
#Inflammatory foods
Processed foods
Refined sugar
grains
fruit
Starchy vegetables
Omega-6
Processed oils (rapeseed, corn, safflower)
soda

When most people think of a high-fat diet, they immediately think of high cholesterol. A reasonable reaction, considering we've been told for years that a low-fat diet is heart-healthy and a high-fat diet is not. But a growing body of research shows that fat is not something to be feared, but rather a scapegoat for the real culprits of Americans' cardiovascular and obesity problems: processed carbohydrates and high-sugar diets.

Many people on a ketogenic diet experience a decrease in total cholesterol, a decrease in triglycerides, and an increase in HDL. Some people may experience an increase in cholesterol on a ketogenic diet, but these people would likely see an increase anyway, as rapid weight loss, whether from water or body fat, can cause a temporary, short-term increase in LDL cholesterol. Therefore, it is often recommended to wait six months after starting the ketogenic diet to test lipid levels, or to wait until weight loss wears off.

Because you cut out sugar and most carbohydrates on a keto diet, it's not hard to see why this diet is so good for blood sugar control. The less sugar and carbs you eat, the less sugar there is in your bloodstream. That's why most people notice a drop in their blood sugar almost immediately after starting a keto diet. In fact, the effects are so immediate that diabetics who start a ketogenic diet are advised to work with their doctor so they can adjust their medications as needed while their blood sugar levels drop and stabilize.

When you eat high-carb, high-glycemic foods, your blood sugar levels rise immediately after eating, followed by a subsequent drop in blood sugar levels. On a ketogenic diet, you reduce your sugar and carbohydrate intake, naturally preventing your blood sugar levels from rising and falling dramatically. While blood sugar levels will still rise slightly when you eat low-glycemic foods, you won't experience the high-low blood sugar swings that occur on a high-carb diet.

Also, as mentioned earlier, by cutting back on carbs, you are depriving your body of glucose stores, so your body will start using fats instead of carbs/glucose for fuel. This will lower your insulin levels because your body no longer has to deal with a large amount of sugar.

People with insulin resistance also benefit from the ketogenic diet. When insulin resistance occurs, the body does not respond to insulin as it should. This often leads to elevated blood sugar levels and, over time, can lead to diabetes and an increased risk of heart disease. Studies of diabetics who have undergone a ketogenic diet show that participants saw a dramatic reduction in their blood sugar-lowering medications and their fasting blood sugar levels.

People with diabetes often experience impressive reductions in blood sugar levels when following a ketogenic diet. This applies to both type 1 and type 2 diabetes.

Dozens of controlled studies show that very-low-carbohydrate diets help control blood sugar levels and may also provide other health benefits ( 25 , 26 , 27 ).

In a 16-week study, 17 of 21 people on a ketogenic diet were able to stop or reduce the dosage of their diabetes medications. Study participants also lost an average of 19 pounds (8.7 kg) and reduced their waist circumference, triglycerides and blood pressure ( 28 ).

In a three-month study comparing a ketogenic diet to a moderate-carbohydrate diet, HbA1c levels decreased by an average of 0.6% in participants in the ketogenic group. 12% of participants achieved an HbA1c level below 5.7%, which is considered normal ( 29 ).

Anyone suffering from high blood pressure will appreciate the positive blood pressure control that comes from a ketogenic diet.

In studies of obese patients, those on a ketogenic diet had more dramatic reductions in blood pressure than those on a low-fat diet. At the same time, the same subjects on a ketogenic diet had comparable results in weight loss and triglycerides to study participants on a low-fat diet and taking a weight loss medication. Additionally, systolic blood pressure decreased in the ketogenic group (which is good for lowering high blood pressure), while it increased in participants on the low-fat diet and taking medication.

When you hear the term "heart health," you think of the little heart symbol you see on whole grains and cereals, promoting low-carb, low-fat foods. But in fact, a low-carb, high-fat diet has been shown to dramatically improve biomarkers associated with heart disease.

In a recent study of a group of normal-weight, normolipidemic men (men with normal blood lipid levels) who followed a ketogenic diet for six weeks, 22 of 26 biomarkers for cardiovascular disease risk improved significantly.

While some people experience a small increase in LDL cholesterol while on a ketogenic diet, it is now believed that LDL cholesterol is not the determining factor for heart health that was once thought to be. A randomized 2.7-year trial examining the impact of the Mediterranean diet on people who had already had a heart attack found a significant reduction in the number of recurrent heart attacks and overall mortality. Most notably, LDL levels did not change between the two groups.

It is well known that the particle size of LDL plays a major role in determining heart health risk. The size of circulating LDL particles is quite variable, and the smaller, denser particles (which contain relatively fewer triglycerides) are associated with vascular damage and heart disease.

The brain loves the keto diet as much as the heart does. The ketogenic diet was originally introduced at the Mayo Clinic in 1924 as a therapeutic measure to treat neurological disorders, particularly epileptic seizures. In a randomized clinical trial, researchers started the ketogenic diet on pediatric patients who suffered from two or more weekly seizures and were taking anti-seizure medications. Within three months of starting the diet, 34 percent of participants experienced a 90 percent reduction in seizures!

But research doesn't stop at epilepsy. In recent years, the ketogenic diet has begun to be studied as a complementary measure for various neurological disorders. While many scientists in the field of neurology believe that the brain prefers glucose over ketones, over time (and as we age), the brain loses the ability to efficiently fuel itself with glucose alone. This is where ketones come into play.

Ketones are a natural neuroprotective antioxidant that has been shown to block harmful reactive oxygen species from damaging the brain. Ketones have been shown to increase mitochondrial efficiency and production, which protects brain cells from stroke and neurodegenerative diseases such as Alzheimer's and Parkinson's.

Finally, a ketogenic diet has been shown to help regulate glutamate (a dominant neurotransmitter in our brain), which can damage nerve cells when overstimulated.

While research into the ketogenic diet and the brain is still in its infancy, the results so far are promising and indicate that further research is needed to fully understand the scope of the benefits and clinical applications.

Although genetics plays a major role in acne, there is evidence that a ketogenic diet may help improve skin clarity.

Specific research on a ketogenic diet and the occurrence of acne has not yet been published, but there are studies that have examined a ketogenic diet in relation to hormone balance, particularly PCOS (polycystic ovary syndrome). Women who suffer from PCOS often struggle with insulin resistance, hormone imbalances, fatigue, unwanted hair growth, infertility and acne. Recent studies have examined the ketogenic diet and low-carb diets in women with PCOS and found that they were able to lower their insulin levels and reduce their body mass.

But how does this affect acne? Well, a recent study in which researchers looked at the benefits of a low-glycemic diet on acne showed that as insulin levels decreased, the physical appearance of acne also seemed to decrease. Additionally, the keto diet has been shown to have anti-inflammatory effects, which in turn helps reduce the inflammation (red and swollen pustules) associated with acne.

Migraines, a recurring type of headache that can cause severe pain, plague nearly 12 percent of Americans. So those who suffer from migraines are naturally willing to try most solutions to get rid of them. Even if migraines were not the primary reason for starting the ketogenic diet, many migraine sufferers who use the ketogenic diet have reported a significant reduction in migraines, and in some cases, even freedom from migraines!

There are a handful of studies that have examined the association between a ketogenic diet and migraines. In one study, participants in the ketogenic diet group reported a decrease in headache frequency and medication use. It was hypothesized that this success may be due to the improvement of mitochondrial metabolism in the brain and the inhibitory effect on neuronal inflammation and cortical spreading depression. The ketogenic VLCD (very low-calorie diet) may play a transient role in antagonizing ponderal increase, a common side effect of prophylactic migraine treatments.

Some studies suggest that migraine symptoms often improve in people who follow a ketogenic diet ( 94 , 95 , 96 ).

An observational study reported that migraine frequency and pain medication use decreased in people who followed a ketogenic diet for one month ( 96 ).

In an interesting case study of two sisters who followed a cyclical ketogenic diet for weight loss, it was reported that their migraine headaches disappeared during the 4-week ketogenic cycles but returned during the 8-week transition diet cycles ( 97 ).

However, high-quality studies are needed to confirm the results of these reports.

When you hear about keto as a cancer therapy, most people are referring to the Warburg effect, in which cancer cells prefer anaerobic (without oxygen) glycolysis for energy.

This is far less efficient than aerobic glycolysis and means that cancer cells have a much higher need for glucose for energy. This is the basis for the PET scan, which involves injecting glucose into the body to detect cancer. Because cancer takes up glucose much more quickly than normal cells, the test tracks the activity and location of the cancer in the body by noting what happens to the injected glucose.

But now comes the most interesting part: some cancers lack the ability to metabolize ketone bodies. This means that if such a cancer does not have access to sugar as an energy source, it cannot thrive. In these cases, a ketogenic diet essentially "starves" the cancer cells. Unfortunately, not all cancers respond in the same way, and the Warburg effect does not occur in all cancers.

However, there is promising research on the role of a ketogenic diet as an effective adjunct to cancer treatment. In a study on neuroblastoma, a cancer that primarily affects children, the ketogenic diet significantly reduced tumor growth and prolonged the survival of the test subjects (in this case, mice).

There are a growing number of preclinical studies investigating the ketogenic diet as an adjunct therapy in cancer treatment, either alone and/or in combination with conventional therapy. In addition to neuroblastoma, the strongest evidence for the tumor-suppressing effect of a ketogenic diet has been found in glioblastoma (a brain tumor), prostate, colon, pancreatic and lung cancer.

In recent years, scientific research has shown that a ketogenic diet may help treat some types of cancer when used along with conventional treatments such as chemotherapy, radiation and surgery ( 30 ).

Many researchers note that elevated blood sugar, obesity, and type 2 diabetes are linked to breast cancer and other cancers. They suspect that restricting carbohydrates to lower blood sugar and insulin levels may help prevent tumor growth ( 31 , 32 ).

Studies in mice show that a ketogenic diet can reduce the progression of several types of cancer, including cancers that have spread to other parts of the body ( 33 , 34 ).

However, some experts believe that the ketogenic diet may be particularly beneficial for brain tumors ( 37 ).

Case studies and analyses of patient data have shown improvements in several types of brain cancer, including glioblastoma multiforme (GBM)—the most common and aggressive form of brain cancer ( 39 , 40 , 41 ).

One study found that 6 out of 7 GBM patients responded moderately to a zero-calorie ketogenic diet combined with a cancer drug. The researchers noted that the diet is safe but likely of limited benefit ( 42 ).

Some researchers report preservation of muscle mass and slowed tumor growth in cancer patients who follow a ketogenic diet in conjunction with radiation or other cancer therapies ( 43 , 44 ).

Although the ketogenic diet may not have a significant impact on disease progression in advanced and terminal cancer, it has been shown to be safe in these patients and may improve quality of life ( 45 , 46 ).

Randomized clinical trials are needed to investigate how ketogenic diets affect cancer patients, and several are currently underway or in the recruitment process.