Low carb and ketogenic diets offer several health benefits.
For example, it is generally known that they can aid with weight loss and diabetes management. They are, nonetheless, adequate for some brain problems.
This article investigates how low carb and ketogenic diets influence the brain.
What are low carb and ketogenic diets?
Although there is some overlap between the low carb and ketogenic diets, there are a few key distinctions.
Low carb diets:
- Carbs are generally limited to 50-130 grams daily (1).
- Protein is not usually limited.
- Ketones in the blood may or may not reach high levels. Ketones are chemicals that can partially replace carbs as a brain energy source.
Ketogenic diet:
- Carb consumption is restricted to 20-50 grams per day.
- Protein is frequently limited.
- One primary objective is to raise blood ketone levels.
The brain will still rely on glucose, the sugar in your blood, for sustenance on a regular low carb diet. The brain, on the other hand, may burn more ketones than on a usual diet.
Ketones are the principal fuel source for the brain on a ketogenic diet. When carbohydrate consumption is very low, the liver creates ketones.
The ‘130 grams of carbs’ myth
You’ve probably heard that your brain needs 130 grams of carbs daily to function correctly. This is one of the most prevalent misconceptions regarding what makes a healthy carbohydrate consumption.
In reality, the National Academy of Medicine’s Food and Nutrition Board said in a 2005 report:
“The lower limit of dietary carbohydrates compatible with life apparently is zero, provided that adequate amounts of protein and fat are consumed” (2).
Although a zero-carb diet is not suggested since it removes many beneficial foods, you may consume fewer than 130 grams of carbs daily and retain normal brain function.
How low carb and ketogenic diets supply energy for the brain
Low carb diets provide energy to your brain through ketogenesis and gluconeogenesis.
Ketogenesis
Glucose is the brain’s primary fuel. Unlike your muscles, your brain cannot use fat as fuel.
However, ketones can be used by the brain. When your glucose and insulin levels are low, your liver converts fatty acids into ketones.
Ketones are created in small amounts if you go for long periods without eating, such as after a good night’s sleep.
However, when fasting or carb consumption falls below 50 grams per day, the liver raises its synthesis of ketones even more (3).
When carbs are avoided or reduced, ketones can provide up to 75% of the brain’s energy requirements (4).
Gluconeogenesis
Although most of the brain can function on ketones, some areas still require glucose to function. The minimal quantity of carbs taken on a very low carb diet can supply some of this glucose.
The rest comes from gluconeogenesis, which means “creating new glucose” in your body. The liver produces glucose for the brain to consume throughout this process. The liver produces glucose by using amino acids, which are the building blocks of protein (5).
Glycerol can also be converted into glucose by the liver. Glycerol is the backbone that connects fatty acids to produce triglycerides, the body’s fat storage form.
The regions of the brain that require glucose have a consistent supply thanks to gluconeogenesis, even if your carb consumption is relatively low.
Low carb/ketogenic diets and epilepsy
Epilepsy is a neurological disorder characterized by seizures caused by periods of overexcitement in brain cells.
It can induce uncontrollable jerks and loss of consciousness.
Epilepsy may be extremely difficult to treat. There are several forms of seizures, and some patients experience multiple episodes every day.
Despite the fact that there are numerous effective antiseizure medicines, they are only effective in roughly 30% of patients. Refractory epilepsy is a kind of epilepsy that is resistant to treatment (6).
In the 1920s, Dr. Russell Wilder created the ketogenic diet to treat drug-resistant epilepsy in youngsters. His diet contains at least 90% fat calories and has been demonstrated to replicate the anti-seizure benefits of fasting (7).
The precise mechanisms behind the antiseizure benefits of the ketogenic diet are uncertain (7).
Low carb and ketogenic diet options to treat epilepsy
Four types of carbohydrate-restricted diets can be used to treat epilepsy. Their usual macronutrient breakdowns are as follows:
- Classic ketogenic diet (KD): Carbohydrates account for 2-4% of calories, 6-8% protein, and fat for 85-90% (8).
- Modified Atkins diet (MAD): In most circumstances, 10% of calories should come from carbohydrates, with no restrictions on protein. The diet begins with 10 g of carbs per day for children and 15 g for adults, with the possibility of minor increases if tolerated (9).
- Medium-chain triglyceride ketogenic diet (MCT diet): 10% carbohydrates, 20% protein, 60% medium-chain triglycerides, and 10% other fats at first (10).
- Low glycemic index treatment (LGIT): Carbs account for 10-20% of calories, protein accounts for 20-30%, and fat accounts for the remainder. Limits carb options to those with a glycemic index (GI) of less than 50 (11).
The classic ketogenic diet in epilepsy
Several epileptic treatment clinics have employed the traditional ketogenic diet (KD). Over half of the research participants improved in many trials (12, 13, 14, 15, 16).
In a 2008 research, children treated with a ketogenic diet for three months saw a 75% reduction in baseline seizures (15).
A 2009 research found that one-third of children who responded to the diet saw a 90% or higher reduction in seizures (16).
In a 2020 research on refractory epilepsy, children who followed the conventional ketogenic diet for six months had a 66% drop in seizure frequency (17).
Although the traditional ketogenic diet can be very effective against seizures, it must be closely monitored by a neurologist and a dietitian.
Food options are very restricted. As a result, the diet can be challenging to adhere to, especially for older children and adults (18).
The modified Atkins diet in epilepsy
In many situations, the modified Atkins diet (MAD) is as successful or nearly as effective as the standard ketogenic diet for controlling pediatric epilepsy, with fewer adverse effects (19, 20, 21, 22, 23).
In a randomized trial of 102 youngsters, 30% of those following the modified Atkins diet had 90% or fewer seizures (21).
Although the majority of the research has been done on children, some adults with epilepsy have experienced positive outcomes with this diet (22, 25, 26).
In an analysis of ten trials comparing the standard ketogenic diet to the modified Atkins diet, people were substantially more likely to keep to the modified Atkins diet (26).
The medium-chain triglyceride ketogenic diet in epilepsy
Since the 1970s, the medium-chain triglyceride ketogenic diet (MCT) has been employed. MCTs, or medium-chain triglycerides, are saturated fats from coconut and palm oil.
MCTs, unlike long-chain triglyceride fats, may be utilized by the liver for rapid energy or ketone synthesis.
The potential of MCT oil to boost ketone levels with less carb restriction has made the MCT diet a popular alternative to other low carb diets (11, 27, 28).
In one research on youngsters, the MCT diet was just as beneficial as the traditional ketogenic diet in controlling seizures (28).
The low glycemic index treatment in epilepsy
Despite its small influence on ketone levels, low glycemic index therapy (LGIT) is another dietary method that can help control epilepsy. It first appeared in 2002 (29).
In a 2020 research on children with refractory epilepsy, those who followed the LGIT diet for six months had fewer seizures and much fewer side effects than those who followed the standard ketogenic diet or modified Atkins diet (17).
Low carb/ketogenic diets and Alzheimer’s disease
Although there has been little official research, it appears that low carb and ketogenic diets may be advantageous for patients with Alzheimer’s disease.
The most frequent type of dementia is Alzheimer’s disease. It is a degenerative condition in which plaques and tangles form in the brain, causing memory loss.
Many experts feel it should be classified as “type 3” diabetes since the brain’s cells become insulin-resistant and unable to correctly utilize glucose, resulting in inflammation (30, 31, 32).
Indeed, metabolic syndrome, a prelude to type 2 diabetes, raises the risk of Alzheimer’s disease (33, 34).
According to experts, Alzheimer’s disease shares several characteristics with epilepsy, such as brain excitability that leads to seizures (35, 36).
In a 2009 research of 152 persons with Alzheimer’s disease, those who took an MCT supplement for 90 days had significantly greater ketone levels and improved brain function as compared to a control group (37).
In one-month research conducted in 2018, persons with Alzheimer’s disease who consumed 30 grams of MCT per day exhibited a substantial boost in brain ketone consumption. Their brains used twice as much ketones as before the research (38).
Animal studies show that a ketogenic diet may be an effective method to feed an Alzheimer’s-affected brain (32, 39).
Researchers are unsure of the specific mechanism behind these possible advantages against Alzheimer’s disease, as they are with epilepsy.
According to one idea, ketones protect brain cells by lowering reactive oxygen species. These are byproducts of metabolism that might promote inflammation (37, 40).
Another notion is that a high-fat diet, incredibly saturated fat, helps minimize the toxic proteins collected in Alzheimer’s patients’ brains (41).
A recent evaluation of data, on the other hand, indicated that a high diet of saturated fat was highly connected with an elevated risk of Alzheimer’s (42).
Other benefits for the brain
Although less researched, low carb and ketogenic diets may offer various potential benefits for the brain:
- Memory. Following a very low carb diet for 6-12 weeks improved cognition in older persons at risk of Alzheimer’s disease. These are modest studies, but the findings are promising (43, 44).
- Brain function. The ketogenic diet improves brain function in elderly and obese mice (45, 46).
- Congenital hyperinsulinism. Low blood sugar levels are caused by congenital hyperinsulinism, which can cause brain damage. A ketogenic diet is effective in treating this illness (47).
- Migraine. Low carb or ketogenic diets, according to researchers, may give migraine relief (48, 49).
- Parkinson’s disease. One tiny randomized controlled experiment compared the ketogenic diet to a low fat, high carb diet. People who followed a ketogenic diet improved significantly in pain and other nonmotor symptoms of Parkinson’s disease (50).
Potential problems with low carb and ketogenic diets
A low carb or ketogenic diet is not suggested for some medical issues. Pancreatitis, liver failure, and other uncommon blood illnesses are among them (51).
If you have a medical issue, see your doctor before beginning a ketogenic diet.
Side effects of low carb or ketogenic diets
People react to low carb and ketogenic diets in a variety of ways. Here are a few possible side effects:
- Elevated cholesterol. Elevated cholesterol and triglyceride levels in children are possible. This, however, appears to be transitory and has little effect on heart health (52, 53).
- Kidney stones. Kidney stones are uncommon. However, they have developed in some children who are on a ketogenic diet for epilepsy. Potassium citrate is commonly used to treat kidney stones (54).
- Constipation. Constipation is a typical side effect of ketogenic diets. According to one treatment clinic, 65% of youngsters suffered constipation. Stool softeners or dietary adjustments are frequently effective treatments (54).
Once seizures have stopped, children with epilepsy cease the ketogenic diet.
One research looked at children who had been on the ketogenic diet for an average of 1.4 years. The majority of them did not suffer any long-term consequences as a result (55).
Tips for adapting to the diet
You may suffer specific side effects while switching to a low carb or ketogenic diet.
You may have headaches, fatigue, or lightheadedness for a few days. This is referred to as “keto flu” or “low carb flu.”
Here are some ideas to help you get through the adaption period:
- Make sure to get enough fluid. Drink at least 68 ounces (2 liters) of water each day to restore the water loss that happens often during the early stages of ketosis.
- Eat more salt. Add 1-2 grams of salt daily to restore the quantity lost in your urine when you cut back on carbs. Drinking broth will assist you in meeting your higher salt and hydration requirements.
- Supplement with potassium and magnesium. Consume potassium and magnesium-rich meals to avoid muscular cramps. Avocado, Greek yogurt, tomatoes, and salmon are all high in this nutrient.
- Moderate your physical activity. Don’t do any strenuous activity for at least a week. It may take a few weeks to adapt to the keto diet appropriately. Don’t push yourself in the gym until you’re ready.
The bottom line
According to the data, ketogenic diets can have significant benefits for the brain.
The most compelling evidence comes from treating drug-resistant epilepsy in youngsters.
There is also tentative evidence that ketogenic diets may lessen Alzheimer’s and Parkinson’s disease symptoms. Its effects on patients with these and other brain illnesses are still being studied.
These diets aren’t for everyone, and it’s a good idea to consult your doctor before starting one.
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