Low carb and ketogenic diets have many health benefits.

For example, it is well known that they can cause weight loss and help fight diabetes.

However, they are also beneficial for certain brain disorders.

This article explores how low carbohydrate and ketogenic diets affect the brain.

What are low carb and ketogenic diets?

Although there is a lot of overlap between low carb and ketogenic diets, there are also some important differences .

Ketogenic Diet:

  • Carbohydrates are limited to 50 grams or less per day.
  • Protein is often restricted.
  • An important objective is to increase the levels of ketones in the blood, molecules that can partially replace carbohydrates as a source of energy for the brain.

Low carb diet:

  • Carbohydrates can vary from 25 to 150 grams per day.
  • Protein is usually not restricted.
  • Ketones may or may not rise to high levels in the blood.

In a ketogenic diet , the brain is fed primarily by ketones. These occur in the liver when carbohydrate intake is very low.

In a standard low carb diet, the brain will continue to rely heavily on glucose , although it can burn more ketones than in a regular diet.

►In summary:

Low carb and ketogenic diets are similar in many ways. However, ketogenic diets contain even less carbohydrates and cause a significant increase in blood ketone levels.

The myth of the “130 grams of carbohydrates”

You may have heard that your brain needs 130 grams of carbohydrates a day to function properly. This is one of the most common myths about low carb diets.

In fact, a report by the Nutrition and Food Committee of the US Institute of Medicine. UU. says :

“The lower limit of carbohydrates compatible with life is zero, provided adequate amounts of protein and fat are consumed.”

Although a carbohydrate-free diet is not recommended because it eliminates many healthy foods, you can definitely eat much less than 130 grams per day and maintain good brain function.

►In summary:

It is a common myth that you have to eat 130 grams of carbohydrates a day to provide energy to the brain.

How low carb and ketogenic diets provide energy for the brain

Low carb diets have a fascinating way to provide energy to your brain through processes called ketogenesis and gluconeogenesis.


Glucose, the sugar found in the blood , is usually the main fuel in the brain. Unlike muscles, your brain cannot use fat as a source of fuel.

However, the brain can use ketones. Your liver produces ketones from fatty acids when glucose and insulin levels are low.

Ketones are produced in small quantities every time you spend many hours without eating, such as after a full night of sleep .

However, the liver further increases its ketone production during fasting or when carbohydrate intake drops below 50 grams per day .

When carbohydrates are eliminated or minimized, ketones can provide up to 70% of the brain’s energy needs.


Although most of the brain can use ketones, there are portions that require glucose to work. In a very low carbohydrate diet , some of this glucose can be supplied by the small amount of carbohydrates consumed.

The rest comes from a process in your body called gluconeogenesis , which means ” making new glucose . ” In this process, the liver creates glucose for the brain to use . Manufactures glucose using amino acids, the building blocks of protein.

The liver can also produce glucose from glycerol. This is the spine that binds fatty acids into triglycerides, the body’s storage form of fat.

Thanks to gluconeogenesis, the parts of the brain that need glucose receive a constant supply, even when carbohydrate intake is very low.

►In summary:

In a very low carb diet, up to 70% of the brain can be fed by ketones. The rest can be fed by the glucose produced in the liver.

Low carb diets and epilepsy

Epilepsy is a disease characterized by seizures , related to periods of overexcitation in brain cells.

It can cause uncontrolled jerking movements and loss of consciousness and occurs most often in children.

Epilepsy can be very difficult to treat effectively . There are several types of seizures and some children have multiple episodes every day.

Although there are many effective anticonvulsant medications , these medications cannot control seizures in at least 30% of patients. This type of epilepsy is called refractory or does not respond to medications.

The ketogenic diet was developed by Dr. Russell Wilder in 1921 to treat drug- resistant epilepsy in children. Their diet provides about 90% of the calories in fats and has been shown to mimic the beneficial effects of starvation in seizures.

The exact mechanisms behind the anticonvulsant effects of the ketogenic diet are still unknown .

Ketogenic and low carb diet options to treat epilepsy

There are four types of carbohydrate-restricted diets that are used to treat epilepsy:

  1. Classic Ketogenic Diet (KD): 2-4% of carbohydrate calories, 6-10% of proteins and 85-90% of fats.
  2. Modified Atkins Diet (DMA): 4-6% of carbohydrate calories without protein restriction in most cases. The diet begins by allowing 10 grams of carbohydrates per day for children and 15 grams for adults, with slight potential increases if tolerated.
  3. Ketogenic Diet of Medium Chain Triglycerides (MCT Diet): Initially 20% carbohydrates, 10% protein, 50% medium chain triglycerides and 20% other fats.
  4. Low glycemic index treatment (LGIT): Limits carbohydrate options to those with a glycemic index below 50. About 20-30% of calories come from protein, 10-20% of carbohydrates and the rest of the fat

The classic ketogenic diet in epilepsy

The classical ketogenic diet (KD) has been used in several epilepsy treatment centers and some studies have found improvement in approximately half of the patients .

In fact, one third of children who respond to diet have a 90% or more decrease in seizures.

In one study, children treated with a ketogenic diet for three months had a 75% decrease in initial seizures , on average.

Although the classical ketogenic diet can be very effective against seizures, it requires the close supervision of a neurologist and a dietitian. Food options are also quite limited, and the diet can be difficult to follow, especially for older children and adults.

The modified Atkins diet in epilepsy

In many cases, the modified Atkins diet (DMA) has proven to be as effective or almost as effective for the treatment of childhood seizures as the classical ketogenic diet, with fewer side effects.

In a randomized study of 102 children, 30% of those who followed the modified Atkins diet experienced a reduction of 90% or more in seizures.

Although most studies have been conducted in children, some adults with epilepsy have also seen good results with this diet.

In an analysis of ten studies comparing the classical ketogenic diet with the modified Atkins diet, people were much more likely to follow the modified Atkins diet .

The ketogenic diet of medium chain triglycerides in epilepsy

The ketogenic medium chain triglyceride diet (MCT Diet) has been used since the 1970s . MCTs are saturated fats found in coconut oil and palm oil .

Unlike long chain fats, they can be used for rapid energy or ketone production by the liver.

The ability of MCT oil to increase ketone levels with less restriction in carbohydrate intake has made the MCT diet a popular alternative to the others .

A study in children found that the MCT diet was comparable in effectiveness to the classical ketogenic diet to control seizures.

The treatment of low glycemic index in epilepsy

Low glycemic index treatment (LGIT) is another dietary approach that can control epilepsy , despite its very modest effect on ketone levels .

In a study of 11 patients who followed the LGIT, eight had a more than 50% reduction in seizures, and half of those patients were completely free of seizures .

►In summary:

Several types of low carb and ketogenic diets are effective in reducing seizures in patients with drug resistant epilepsy.

Low carb and ketogenic diets and Alzheimer’s disease

Although there have been few formal studies, it seems that low-carb and ketogenic diets may be beneficial for people with Alzheimer’s disease.

Alzheimer ‘s disease is the most common form of dementia. It is a progressive disease in which the brain develops plaques and clews that cause memory loss.

Many researchers believe that “type 3” diabetes should be considered because brain cells become resistant to insulin and cannot use glucose properly, which leads to inflammation.

In fact, metabolic syndrome, a step towards type 2 diabetes , also increases the risk of developing Alzheimer’s disease .

Experts report that Alzheimer’s disease shares certain characteristics with epilepsy, including brain excitability that leads to seizures.

In a study of 152 people with Alzheimer’s disease, those who received an MCT supplement for 90 days had much higher ketone levels and significant improvement in brain function compared to a control group.

Animal studies also suggest that a ketogenic diet can be an effective way to feed a brain affected by Alzheimer’s .

As with epilepsy, researchers are not sure of the exact mechanism behind these potential benefits against Alzheimer’s disease.

One theory is that ketones protect brain cells by reducing reactive oxygen species, which are byproducts of metabolism that can cause inflammation.

Another theory is that a diet high in fats , including saturated fats, can reduce the harmful proteins that accumulate in the brains of people with Alzheimer’s.

►In summary:

Ketogenic diets and MCT supplements can improve memory and brain function in people with Alzheimer’s disease, although research is still in its early stages.

Other benefits for the brain

Although these have not been studied so much, low carb and ketogenic diets can have several other benefits for the brain:

  • Memory: Older adults at risk of Alzheimer’s disease have shown an improvement in memory after following a very low carb diet for six weeks.
  • Brain function: Feeding older and obese rats with a ketogenic diet leads to an improvement in brain function.
  • Congenital hyperinsulinism: This condition causes hypoglycemia and can cause brain damage. Congenital hyperinsulinism has been successfully treated with a ketogenic diet.
  • Migraine headaches: Researchers report that low carb or ketogenic diets can provide relief to people suffering from migraine.
  • Parkinson’s disease: In a small uncontrolled study, five out of seven people with Parkinson’s disease who completed a four-week ketogenic diet experienced a 43% improvement in self-reported symptoms.
  • Traumatic brain injury: Patients with severe head injuries who were fed a non-carbohydrate formula were able to nourish themselves while avoiding high blood sugar levels, which can make recovery difficult.

►In summary:

Low carb and ketogenic diets have many other benefits for brain health. They can improve memory in older adults, help reduce migraines and reduce symptoms of Parkinson’s disease, to name a few.

Potential problems with low carb and ketogenic diets

There are certain conditions for which a low carb or ketogenic diet is not recommended .

If you have any type of medical condition , you may want to talk to your doctor before starting a ketogenic diet.

Side effects of low carb or ketogenic diets

People respond to low carb and ketogenic diets in many different ways. Here are some potential adverse effects:

  • High cholesterol: Adults may experience elevated cholesterol levels and children may have increases in both cholesterol and triglyceride levels. However, this may be temporary and does not seem to affect the health of the heart.
  • Kidney stones: These are uncommon, but they have occurred in some children who receive ketogenic dietary therapy for epilepsy. Kidney stones are usually treated with potassium citrate.
  • Constipation: This is very common in ketogenic diets. A treatment center reported that 65% of children developed constipation. Usually, this is easy to remedy with stool softeners or dietary changes.

Children with epilepsy eventually suspend the ketogenic diet once the seizures have resolved. Most of them do not experience any long-term negative effects.

►In summary:

A very low carbohydrate ketogenic diet is safe for most people, but not for everyone. Some people may develop side effects, which are usually temporary.

Tips to adapt to the diet

When transitioning to a low carb or ketogenic diet, you may experience some adverse effects.

You may develop headaches or feel tired or dizzy for a few days. This is known as the “keto flu” or “low carb flu.” Here are some suggestions to overcome the adaptation period:

  • Be sure to get enough fluid: Drink at least 2 liters of water a day to replace the loss of water that often occurs in the initial stages of ketosis.
  • Eat more salt: Add 1-2 grams of salt each day to replace the amount lost in your urine when carbohydrates are reduced. Drinking broth will help you meet your greatest sodium and fluid needs.
  • Supplement with potassium and magnesium: Eat foods rich in potassium and magnesium to prevent muscle cramps. Avocado, Greek yogurt, tomatoes and fish are good sources.
  • Moderate your physical activity: Do not exercise excessively for at least one week. It may take a few weeks for you to fully adapt, so don’t strain your workouts until you feel ready.

►In summary:

Adapting to a very low carb or ketogenic diet takes some time, but there are some ways to facilitate the transition.

These diets have powerful health benefits

According to the available evidence, ketogenic diets can have powerful benefits for the brain.

The strongest evidence has to do with the treatment of drug-resistant epilepsy in children.

There is also preliminary evidence that ketogenic diets can reduce the symptoms of Alzheimer’s and Parkinson’s . Research is ongoing on its effects in patients with these and other brain disorders.

Beyond brain health, there are also many studies that show that low-carb and ketogenic diets can cause weight loss and help treat diabetes.

These diets are not for everyone, but they can have incredible benefits for many people.

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