First, a little background: Eric Westman, MD, director of the Duke Lifestyle Medical Clinic, explained to Health in a previous interview that in order to successfully follow the keto diet, you need to eat moderate amounts of protein, reduce your carb intake, and increase fats. When you reduce your carb consumption, your body turns to stored fat as its new fuel source—a process called ketosis. To stay in ketosis, followers of the keto diet must limit their carbs to 50 grams a day, Dr. Westman says.
Has adding more water, salt and fat not helped very much? Are you still feeling achy, tired and off? We recommend you try to endure it for a few more days until the symptoms pass. Research has shown that a very-low-carb diet is best for weight loss and metabolic issues like type 2 diabetes.Keto flu symptoms are only temporary – they’ll be long gone when you are a fat burner.
Although many hypotheses have been put forward to explain how the ketogenic diet works, it remains a mystery. Disproven hypotheses include systemic acidosis (high levels of acid in the blood), electrolyte changes and hypoglycaemia (low blood glucose).[19] Although many biochemical changes are known to occur in the brain of a patient on the ketogenic diet, it is not known which of these has an anticonvulsant effect. The lack of understanding in this area is similar to the situation with many anticonvulsant drugs.[56]
Flour, wheat products or other refined cereal grains, even if labelled “gluten free.” This means bread, buns, pasta, crackers, porridge, muesli. Whole grains are included here too – on a low-carb diet they are just less bad. Also potatoes (sweet potatoes too), potato chips, French fries, corn products and popped corn, rice. Do check out, however, some of the low-carb versions of these foods:

Wondering what fits into a keto diet — and what doesn’t? “It’s so important to know what foods you’ll be eating before you start, and how to incorporate more fats into your diet,” says Kristen Mancinelli, RD, author of The Ketogenic Diet: A Scientifically Proven Approach to Fast, Healthy Weight Loss, who is based in New York City. We asked her for some guidelines.
The ketone bodies are possibly anticonvulsant; in animal models, acetoacetate and acetone protect against seizures. The ketogenic diet results in adaptive changes to brain energy metabolism that increase the energy reserves; ketone bodies are a more efficient fuel than glucose, and the number of mitochondria is increased. This may help the neurons to remain stable in the face of increased energy demand during a seizure, and may confer a neuroprotective effect.[56]

In many developing countries, the ketogenic diet is expensive because dairy fats and meat are more expensive than grain, fruit and vegetables. The modified Atkins diet has been proposed as a lower-cost alternative for those countries; the slightly more expensive food bill can be offset by a reduction in pharmaceutical costs if the diet is successful. The modified Atkins diet is less complex to explain and prepare and requires less support from a dietitian.[55]


Still, it can be hard to get enough fat when you first start this diet. Butter, nuts, coconut and olive oils, and fatty cuts of meat are all on the menu. However, don't go overboard with polyunsaturated fats like soybean, corn, or sunflower oil. Keto dieters who increase their intake of those fats often end up with gastrointestinal distress that causes them to jump ship.
Flour, wheat products or other refined cereal grains, even if labelled “gluten free.” This means bread, buns, pasta, crackers, porridge, muesli. Whole grains are included here too – on a low-carb diet they are just less bad. Also potatoes (sweet potatoes too), potato chips, French fries, corn products and popped corn, rice. Do check out, however, some of the low-carb versions of these foods:
During the 1920s and 1930s, when the only anticonvulsant drugs were the sedative bromides (discovered 1857) and phenobarbital (1912), the ketogenic diet was widely used and studied. This changed in 1938 when H. Houston Merritt, Jr. and Tracy Putnam discovered phenytoin (Dilantin), and the focus of research shifted to discovering new drugs. With the introduction of sodium valproate in the 1970s, drugs were available to neurologists that were effective across a broad range of epileptic syndromes and seizure types. The use of the ketogenic diet, by this time restricted to difficult cases such as Lennox–Gastaut syndrome, declined further.[10]
Severely restricting carbohydrates to less than 0.7 ounces (20 grams) a day can result in a process called ketosis. Ketosis occurs when you don't have enough sugar (glucose) for energy, so your body breaks down stored fat, causing ketones to build up in your body. Side effects from ketosis can include nausea, headache, mental and physical fatigue, and bad breath.
Epilepsy is one of the most common neurological disorders after stroke,[7] affecting around 50 million people worldwide.[8] It is diagnosed in a person having recurrent, unprovoked seizures. These occur when cortical neurons fire excessively, hypersynchronously, or both, leading to temporary disruption of normal brain function. This might affect, for example, the muscles, the senses, consciousness, or a combination. A seizure can be focal (confined to a specific part of the brain) or generalised (spread widely throughout the brain and leading to a loss of consciousness). Epilepsy can occur for a variety of reasons; some forms have been classified into epileptic syndromes, most of which begin in childhood. Epilepsy is considered refractory (not yielding to treatment) when two or three anticonvulsant drugs have failed to control it. About 60% of patients achieve control of their epilepsy with the first drug they use, whereas around 30% do not achieve control with drugs. When drugs fail, other options include epilepsy surgery, vagus nerve stimulation, and the ketogenic diet.[7]

If you’ve recently switched to the keto diet and you’re feeling drowsy, achy, nauseous, dizzy, and irritable, don’t worry. These symptoms are your body’s natural reaction to removing carbs from your diet, and while it may have you second guessing your keto diet decision, we promise you these keto flu symptoms will pass. Stick with it, and soon you’ll be reaping the energizing, fat-burning rewards that come with ketosis.


Low-carb diets may improve high-density lipoprotein (HDL) cholesterol and triglyceride values slightly more than do moderate-carb diets. That may be due not only to how many carbs you eat but also to the quality of your other food choices. Lean protein (fish, poultry, legumes), healthy fats (monounsaturated and polyunsaturated) and unprocessed carbs — such as whole grains, legumes, vegetables, fruits and low-fat dairy products — are generally healthier choices.
Although many hypotheses have been put forward to explain how the ketogenic diet works, it remains a mystery. Disproven hypotheses include systemic acidosis (high levels of acid in the blood), electrolyte changes and hypoglycaemia (low blood glucose).[19] Although many biochemical changes are known to occur in the brain of a patient on the ketogenic diet, it is not known which of these has an anticonvulsant effect. The lack of understanding in this area is similar to the situation with many anticonvulsant drugs.[56]

The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control (refractory) epilepsy in children. The diet forces the body to burn fats rather than carbohydrates. Normally, the carbohydrates contained in food are converted into glucose, which is then transported around the body and is particularly important in fueling brain function. However, if little carbohydrate remains in the diet, the liver converts fat into fatty acids and ketone bodies. The ketone bodies pass into the brain and replace glucose as an energy source. An elevated level of ketone bodies in the blood, a state known as ketosis, leads to a reduction in the frequency of epileptic seizures.[1] Around half of children and young people with epilepsy who have tried some form of this diet saw the number of seizures drop by at least half, and the effect persists even after discontinuing the diet.[2] Some evidence indicates that adults with epilepsy may benefit from the diet, and that a less strict regimen, such as a modified Atkins diet, is similarly effective.[1] Potential side effects may include constipation, high cholesterol, growth slowing, acidosis, and kidney stones.[3]
Try gradually reducing your carbohydrate intake by 10 grams a day. Increase your fat consumption each day for satiation and satiety, while keeping your protein the same. This slow tampering down of carbohydrates can help you get into ketosis without experiencing any keto flu symptoms. (Keep in mind that this process can take up to six months depending on how many carbohydrates you are used to eating.)
In many developing countries, the ketogenic diet is expensive because dairy fats and meat are more expensive than grain, fruit and vegetables. The modified Atkins diet has been proposed as a lower-cost alternative for those countries; the slightly more expensive food bill can be offset by a reduction in pharmaceutical costs if the diet is successful. The modified Atkins diet is less complex to explain and prepare and requires less support from a dietitian.[55]
The nerve impulse is characterised by a great influx of sodium ions through channels in the neuron's cell membrane followed by an efflux of potassium ions through other channels. The neuron is unable to fire again for a short time (known as the refractory period), which is mediated by another potassium channel. The flow through these ion channels is governed by a "gate" which is opened by either a voltage change or a chemical messenger known as a ligand (such as a neurotransmitter). These channels are another target for anticonvulsant drugs.[7]

Louise holds a Bachelors and Masters in Natural Sciences from Cambridge University (UK). She attended Columbia University for her JD and practiced law at Debevoise & Plimpton before co-founding Louise's Foods, Paleo Living Magazine, Nourishing Brands, & CoBionic. Louise has considerable research experience but enjoys creating products and articles that help move people just a little bit closer toward a healthy life they love. You can find her on Facebook or LinkedIn.
While cutting down your carb intake all at once may result in faster weight loss, the simple fact is you’re not going to lose any weight unless you stick to that low carb or Keto diet. So, your first priority should be to ensure you’re not going to give up on the diet because you feel too crappy. If that’s going to be the case, then try reducing your carb intake slowly.
By default, your body burns glucose (carbs) as its primary energy source, but when you switch to an extremely low carb diet, your body will begin to burn fatty acids for energy instead. Fat is your body’s secondary or “backup” fuel source, which can only be tapped when there’s not enough glucose in your diet. When your body begins burning fat as fuel instead of carbs, you’ve entered the metabolic state known as ketosis (1).
The original therapeutic diet for paediatric epilepsy provides just enough protein for body growth and repair, and sufficient calories[Note 1] to maintain the correct weight for age and height. The classic therapeutic ketogenic diet was developed for treatment of paediatric epilepsy in the 1920s and was widely used into the next decade, but its popularity waned with the introduction of effective anticonvulsant medications. This classic ketogenic diet contains a 4:1 ratio by weight of fat to combined protein and carbohydrate. This is achieved by excluding high-carbohydrate foods such as starchy fruits and vegetables, bread, pasta, grains, and sugar, while increasing the consumption of foods high in fat such as nuts, cream, and butter.[1] Most dietary fat is made of molecules called long-chain triglycerides (LCTs). However, medium-chain triglycerides (MCTs)—made from fatty acids with shorter carbon chains than LCTs—are more ketogenic. A variant of the classic diet known as the MCT ketogenic diet uses a form of coconut oil, which is rich in MCTs, to provide around half the calories. As less overall fat is needed in this variant of the diet, a greater proportion of carbohydrate and protein can be consumed, allowing a greater variety of food choices.[4][5]
During the 1920s and 1930s, when the only anticonvulsant drugs were the sedative bromides (discovered 1857) and phenobarbital (1912), the ketogenic diet was widely used and studied. This changed in 1938 when H. Houston Merritt, Jr. and Tracy Putnam discovered phenytoin (Dilantin), and the focus of research shifted to discovering new drugs. With the introduction of sodium valproate in the 1970s, drugs were available to neurologists that were effective across a broad range of epileptic syndromes and seizure types. The use of the ketogenic diet, by this time restricted to difficult cases such as Lennox–Gastaut syndrome, declined further.[10]
In a study done with 8 groups of obese individuals, researchers found that different amounts of dietary carbohydrates affect T3 and reverse T3 levels in different ways. T3 levels only decreased when the subjects consumed 120 grams of carbohydrates per day or less (regardless of how calorie-restricted they were). Reverse T3 levels, on the other hand, began to increase when carbohydrate intake was between 40 and 50 grams of carbohydrates per day.
The ketogenic diet is calculated by a dietitian for each child. Age, weight, activity levels, culture, and food preferences all affect the meal plan. First, the energy requirements are set at 80–90% of the recommended daily amounts (RDA) for the child's age (the high-fat diet requires less energy to process than a typical high-carbohydrate diet). Highly active children or those with muscle spasticity require more food energy than this; immobile children require less. The ketogenic ratio of the diet compares the weight of fat to the combined weight of carbohydrate and protein. This is typically 4:1, but children who are younger than 18 months, older than 12 years, or who are obese may be started on a 3:1 ratio. Fat is energy-rich, with 9 kcal/g (38 kJ/g) compared to 4 kcal/g (17 kJ/g) for carbohydrate or protein, so portions on the ketogenic diet are smaller than normal. The quantity of fat in the diet can be calculated from the overall energy requirements and the chosen ketogenic ratio. Next, the protein levels are set to allow for growth and body maintenance, and are around 1 g protein for each kg of body weight. Lastly, the amount of carbohydrate is set according to what allowance is left while maintaining the chosen ratio. Any carbohydrate in medications or supplements must be subtracted from this allowance. The total daily amount of fat, protein, and carbohydrate is then evenly divided across the meals.[37]
Before starting, ask yourself what is really realistic for you, Mattinson suggests. Then get your doctor’s okay. You may also work with a local registered dietitian nutritionist to limit potential nutrient deficiencies and talk about vitamin supplementation, as you won’t be eating whole grains, dairy, or fruit, and will eliminate many veggies. “A diet that eliminates entire food groups is a red flag to me. This isn’t something to take lightly or dive into headfirst with no medical supervision,” she says.
"It was extremely difficult," he recalls. "You spend your entire life hearing that fat makes you fat and causes heart attacks and strokes. Now, all of a sudden, you're eating 200 grams of fat per day. There is a huge psychological component to conquer before you can become successful with the keto diet. In the beginning, it's like trying to convince people 1,000 years ago that the world is in fact round, not flat."
When something is popular, it’s pretty much a guarantee that people are going to come up with new or easier ways of doing it. Enter the lazy keto and dirty keto diets. With lazy keto, people try to limit their carb intake to 20 to 50 grams a day but don’t really track it; with dirty keto, people generally follow the same macronutrient breakdown as "regular" keto, but it doesn't matter where those macronutrients come from.

Keatley has some…thoughts about those. “Dirty keto is a waste of your time since good habits have not been developed and it is simply too easy to fall back into a high-calorie diet,” he says. If you’re trying to do a lazy keto diet, he recommends following the USDA’s MyPlate instead and monitoring your meals based on proportions vs. macros. “It’s easier, more flexible, and has shown, when combined with moderate exercise, to be effective over the long term,” he says.

From a genetic perspective, certain people are less metabolically flexible because they have genetic variations (e.g., insufficient production of specific enzymes) that make it more difficult for them to adapt to the ketogenic diet. In contrast, those who are quick keto-adapters may be gifted with genes that enhance their ability to switch between fuel sources more efficiently.
A small Feb. 20, 2017, study looked at the impact of a six-week ketogenic diet on physical fitness and body composition in 42 healthy adults. The study, published in the journal Nutrition & Metabolism, found a mildly negative impact on physical performance in terms of endurance capacity, peak power and faster exhaustion. Overall, researchers concluded, “Our findings lead us to assume that a [ketogenic diet] does not impact physical fitness in a clinically relevant manner that would impair activities of daily living and aerobic training.” The “significant” weight loss of about 4.4 pounds, on average, did not affect muscle mass or function.
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