The answer to this question is often individualized and will depend on the metabolic state of each individual. One can enter a state of ketosis after an overnight fast. However, this slight elevation may not be high enough to allow for your body to efficiently utilize these ketones as a primary fuel source. Over time, as you become more adapted, your body will consistently be producing AND utilizing ketones. For some, this could take as little as one week, however, for others, it could take several weeks to accomplish. The length of time it takes to become keto-adapted also greatly depends on the composition of the ketogenic diet utilized (i.e., 20 grams versus 50 grams of carbohydrates per day) as well as personal activity level.
Body Composition: Physical changes in the body are one of the primary reasons people are attracted to and implement low-carbohydrate diets. By definition, being in a state of ketosis means you are able to tap into the body’s fat stores, metabolizing fat for immediate energy and producing ketones for fuel. Furthermore, the ketogenic diet has been shown to reduce circulating insulin levels, which may lead to less storage of fat by the hormone insulin.[6] While both “low-carbohydrate” and ketogenic diets are effective for weight loss, studies have demonstrated that the ketogenic diet is superior.[1]

Take a 2 – 3 cups of lettuce, crumble in some bacon and dice a medium tomato. Mix that with two or three tablespoons of mayo, and toss after adding some splashes of hot sauce. Delicious, filling, full of fiber and healthy fats, and absolutely easy. I know the mayo sounds weird as a dressing, but trust us; it’s amazing! Add in some avocado chunks to boost potassium too!
Aude, Y., A. S, Agatston, F. Lopez-Jimenez, et al. “The National Cholesterol Education Program Diet vs a Diet Lower in Carbohydrates and Higher in Protein and Monounsaturated Fat: A Randomized Trial.” JAMA Internal Medicine 164, no. 19 (2004): 2141–46. doi: 10.1001/archinte.164.19.2141. jamanetwork.com/journals/jamainternalmedicine/article-abstract/217514.

Children who discontinue the diet after achieving seizure freedom have about a 20% risk of seizures returning. The length of time until recurrence is highly variable, but averages two years. This risk of recurrence compares with 10% for resective surgery (where part of the brain is removed) and 30–50% for anticonvulsant therapy. Of those who have a recurrence, just over half can regain freedom from seizures either with anticonvulsants or by returning to the ketogenic diet. Recurrence is more likely if, despite seizure freedom, an electroencephalogram shows epileptiform spikes, which indicate epileptic activity in the brain but are below the level that will cause a seizure. Recurrence is also likely if an MRI scan shows focal abnormalities (for example, as in children with tuberous sclerosis). Such children may remain on the diet longer than average, and children with tuberous sclerosis who achieve seizure freedom could remain on the ketogenic diet indefinitely.[46]

One downside to a ketogenic diet for weight loss is the difficulty maintaining it. “Studies show that weight loss results from being on a low-carb diet for more than 12 months tend to be the same as being on a normal, healthy diet,” says Mattinson. While you may be eating more satiating fats (like peanut butter, regular butter, or avocado), you’re also way more limited in what’s allowed on the diet, which can make everyday situations, like eating dinner with family or going out with friends, far more difficult. Because people often find it tough to sustain, it’s easy to rely on it as a short-term diet rather than a long-term lifestyle.
Early studies reported high success rates; in one study in 1925, 60% of patients became seizure-free, and another 35% of patients had a 50% reduction in seizure frequency. These studies generally examined a cohort of patients recently treated by the physician (a retrospective study) and selected patients who had successfully maintained the dietary restrictions. However, these studies are difficult to compare to modern trials. One reason is that these older trials suffered from selection bias, as they excluded patients who were unable to start or maintain the diet and thereby selected from patients who would generate better results. In an attempt to control for this bias, modern study design prefers a prospective cohort (the patients in the study are chosen before therapy begins) in which the results are presented for all patients regardless of whether they started or completed the treatment (known as intent-to-treat analysis).[19]
When it comes to starting the keto diet (or any diet for that matter), there's one thing all experts agree on. You *must* have a plan. "Never try to wing a keto diet," says Julie Stefanski, R.D.N., C.S.S.D., L.D.N., a dietitian based in York, PA, who specializes in the ketogenic diet. "Set a start date and get prepared by reorganizing your pantry, planning out meal and snack options, and purchasing appropriate foods and dietary supplements," she says. "The biggest reason people have a hard time sticking with keto is that people don't have enough interesting foods to turn to, and high-carb favorites win out over good intention. If you didn't buy foods at the grocery store that fit the guidelines, there won't be an easy option in the fridge when you really need it." (A great place to start is this List of High-Fat Keto Foods Anyone Can Add to Their Diet.)
No matter what your diet has been before now, keto will be a big change. If you're coming from a standard American diet (SAD), your carbs will go way down, your protein may either go up or down, and your fat will go way up. If you're coming from a bodybuilding-style diet, your fat intake will jump to alarming levels, and your protein will likely drop significantly.
Because people with type 2 diabetes are at an increased risk for cardiovascular disease, there’s a specific concern that the saturated fat in the diet may drive up LDL, or “bad,” cholesterol levels, and further increase the odds of heart problems. If you have type 2 diabetes, talk to your doctor before attempting a ketogenic diet. They may recommend a different weight-loss diet for you, like a reduced-calorie diet, to manage diabetes. Those with epilepsy should also consult their doctor before using this as part of their treatment plan.
Bonnie J. Brehm, Randy J. Seeley, Stephen R. Daniels, and David A. D’Alessio, “A Randomized Trial Comparing a Very Low Carbohydrate Diet and a Calorie-Restricted Low Fat Diet on Body Weight and Cardiovascular Risk Factors in Healthy Women,” The Journal of Clinical Endocrinology & Metabolism: Vol 88, No 4; January 14, 2009. http://press.endocrine.org/doi/full/10.1210/jc.2002-021480.

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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]


Keto and Traumatic Brain Injury (TBI): Research involving TBI has found that upon immediate trauma to the head, the brain takes up massive amounts of glucose. However, soon thereafter, the brain becomes resistant to taking up and utilizing glucose. This damage leads to insulin resistance and inflammation of brain tissue. The anti-oxidative and anti-inflammatory properties of ketones have been shown to not only reduce inflammation but to reduce glucose uptake in the brain as well. The ketogenic diet may also be a therapeutic treatment option for those individuals who have experienced long-term ramifications of a TBI by providing ketones as an alternative fuel source that can be readily taken up and utilized by the brain following these traumas.
Rami co-founded Tasteaholics with Vicky at the start of 2015 to master the art of creating extremely delicious food while researching the truth behind nutrition, dieting and overall health. You can usually find him marketing, coding or coming up with the next crazy idea because he can’t sit still for too long. His favorite book is The 4-Hour Workweek and artist is Infected Mushroom.
After increasing water intake and replacing electrolytes, it should relieve most all symptoms of Keto Flu. For an average person that is starting a ketogenic diet, eating 20-30g of net carbs a day, the entire adaptation process will take about 4-5 days. My advice is to cut your carbs to fewer than 15g to ensure that you are well on your way into ketosis within one week. If you are experiencing any more keto flu symptoms, double check your electrolyte intake and adjust.

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.

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