A keto diet should be moderately high in protein and will probably be higher in fat, since fat provides the energy that you are no longer getting from carbohydrate. However, too much dietary fat means your body won’t use body fat for energy. Adequate protein is important, but protein above what your body needs can also contribute to excess calories. Avoid low-fat diet products.
Ketogenesis has existed as long as humans have. If you eat a very low amount of carbohydrates, you starve your brain of glucose, its main fuel source. Your body still needs fuel to function, so it taps into your reserve of ketones, which are compounds the liver creates from fat when blood insulin is low. This process is known as ketosis: It’s like when a hybrid car runs out of gas and reverts to pure electricity.
Variations on the Johns Hopkins protocol are common. The initiation can be performed using outpatient clinics rather than requiring a stay in hospital. Often, no initial fast is used (fasting increases the risk of acidosis, hypoglycaemia, and weight loss). Rather than increasing meal sizes over the three-day initiation, some institutions maintain meal size, but alter the ketogenic ratio from 2:1 to 4:1.[9]
The confusion between ketosis and ketoacidosis is a prominent reason why many individuals, particularly doctors, steer clear of the keto diet for beginners. It’s important to understand that these are two very DIFFERENT metabolic states. Ketoacidosis may occur in uncontrolled type 1 diabetics (DKA; diabetic ketoacidosis) due to insulin deficiencies. DKA is associated with both elevated blood glucose and ketone levels; due to little to no insulin production, blood glucose cannot enter insulin-dependent cells to be used for energy, and as such, cells become hungry, resulting in uncontrolled ketone production. In turn, a highly acidic environment is created that can have detrimental effects on an individual’s health, possibly resulting in death. It must be echoed that the ketogenic diet, which induces “nutritional” ketosis, is vastly different and should never be confused with DKA. To put this in perspective, a normal state of ketosis, as achieved via the keto diet for beginners may elevate ketones anywhere from 0.3–5mM, while DKA results in ketone levels of about 15mM or higher.
The confusion between ketosis and ketoacidosis is a prominent reason why many individuals, particularly doctors, steer clear of the keto diet for beginners. It’s important to understand that these are two very DIFFERENT metabolic states. Ketoacidosis may occur in uncontrolled type 1 diabetics (DKA; diabetic ketoacidosis) due to insulin deficiencies. DKA is associated with both elevated blood glucose and ketone levels; due to little to no insulin production, blood glucose cannot enter insulin-dependent cells to be used for energy, and as such, cells become hungry, resulting in uncontrolled ketone production. In turn, a highly acidic environment is created that can have detrimental effects on an individual’s health, possibly resulting in death. It must be echoed that the ketogenic diet, which induces “nutritional” ketosis, is vastly different and should never be confused with DKA. To put this in perspective, a normal state of ketosis, as achieved via the keto diet for beginners may elevate ketones anywhere from 0.3–5mM, while DKA results in ketone levels of about 15mM or higher.
"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."
Supplemental ketosis: This form of ketosis has recently gained momentum in the field of ketogenic dieting. Supplemental ketosis is a ketogenic state that is achieved through the ingestion of ketogenic supplements. Consuming these substances alone does not mean that an individual is “keto-adapted.” While these products can help during the keto-adaptation period, especially if one is experiencing the “keto-flu,” they will only elicit short-term increases in blood ketone levels. Exogenous ketones can acutely produce benefits similar to the ketogenic diet; however, these products are best used in conjunction with a well-formulated keto diet for beginners, or the very at least, a diet that restricts carbohydrates. The commonly used supplements on the market are medium-chain triglyceride (MCT) oil and exogenous ketones. MCT oil is a fat that, in contrast to other longer-chain fatty acids, travels straight from the intestines to the liver where it is readily metabolized. This allows for ketone production in the liver to occur faster than with other fats (long-chain fatty acids have to travel through the lymph and circulatory systems first). Exogenous ketones are synthetic substances that mimic the ketones produced in our body (endogenous ketones). Exogenous ketones can come in the form of ketone salts or ketone esters.
This article was reviewed by Jes Harvey, RD, on November 7, 2019. Harvey is a registered dietitian specializing in the ketogenic diet for children and adults. She is a certified specialist in Pediatric Nutrition and educates children with epilepsy on the ketogenic diet as an anti-seizure medication. Harvey also manages a private nutrition practice consulting adults on the ketogenic way of eating.
In the first week, many people report headaches, mental fogginess, dizziness, and aggravation. Most of the time, this is the result of your electrolytes being flushed out, as ketosis has a diuretic effect. Make sure you drink plenty of water and keep your sodium intake up.6One of the fathers of keto, Dr. Phinney, shows that electrolyte levels (especially sodium) can become unbalanced with low carb intake.
Carbohydrates have been linked to this skin condition, so cutting down on them may help. And the drop in insulin that a ketogenic diet can trigger may also help stop acne breakouts. (Insulin can cause your body to make other hormones that bring on outbreaks.) Still, more research is needed to determine exactly how much effect, if any, the diet actually has on acne. 
Constipation: As mentioned above, the elimination of carbohydrates coupled with the increased release of water may lead to constipation. If this occurs, simply increasing water consumption as well as incorporating more fiber into the diet can alleviate these symptoms. Additionally, some electrolytes like magnesium can also assist with this in higher amounts.
"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."
A systematic review in 2018 looked at 16 studies on the ketogenic diet in adults. It concluded that the treatment was becoming more popular for that group of patients, that the efficacy in adults was similar to children, the side effects relatively mild. However, many patients gave up with the diet, for various reasons, and the quality of evidence was inferior to studies on children. Health issues include high levels of low-density lipoprotein, high total cholesterol, and weight loss.[24]
Because the ketogenic diet alters the body's metabolism, it is a first-line therapy in children with certain congenital metabolic diseases such as pyruvate dehydrogenase (E1) deficiency and glucose transporter 1 deficiency syndrome,[35] which prevent the body from using carbohydrates as fuel, leading to a dependency on ketone bodies. The ketogenic diet is beneficial in treating the seizures and some other symptoms in these diseases and is an absolute indication.[36] However, it is absolutely contraindicated in the treatment of other diseases such as pyruvate carboxylase deficiency, porphyria, and other rare genetic disorders of fat metabolism.[9] Persons with a disorder of fatty acid oxidation are unable to metabolise fatty acids, which replace carbohydrates as the major energy source on the diet. On the ketogenic diet, their bodies would consume their own protein stores for fuel, leading to ketoacidosis, and eventually coma and death.[37]
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Long-term use of the ketogenic diet in children increases the risk of slowed or stunted growth, bone fractures, and kidney stones.[18] The diet reduces levels of insulin-like growth factor 1, which is important for childhood growth. Like many anticonvulsant drugs, the ketogenic diet has an adverse effect on bone health. Many factors may be involved such as acidosis and suppressed growth hormone.[38] About one in 20 children on the ketogenic diet develop kidney stones (compared with one in several thousand for the general population). A class of anticonvulsants known as carbonic anhydrase inhibitors (topiramate, zonisamide) are known to increase the risk of kidney stones, but the combination of these anticonvulsants and the ketogenic diet does not appear to elevate the risk above that of the diet alone.[39] The stones are treatable and do not justify discontinuation of the diet.[39] Johns Hopkins Hospital now gives oral potassium citrate supplements to all ketogenic diet patients, resulting in one-seventh of the incidence of kidney stones.[40] However, this empiric usage has not been tested in a prospective controlled trial.[9] Kidney stone formation (nephrolithiasis) is associated with the diet for four reasons:[39]
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]
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