Here are a few of the most common side effects that I come across when people first start keto. Frequently the issues relate to dehydration or lack of micronutrients (vitamins) in the body. Make sure that you’re drinking enough water (close to a gallon a day) and eating foods with good sources of micronutrients. To read more on micronutrients, click here >
If you think you may have a medical emergency, call your healthcare provider or 911 immediately. Any mention of products or services is not meant as a guarantee, endorsement, or recommendation of the products, services, or companies. Reliance on any information provided is solely at your own risk. Please discuss any options with your healthcare provider.
A ketogenic diet is high in fat and low in carbohydrates. It’s called “ketogenic” because people on this diet shift from using glucose (a type of sugar) as their main fuel source to ketone bodies, which are derived from fat. In other words, people on the ketogenic diet can use their bodies’ fat stores as fuel—and this is why many studies show that this diet is superior for sustainable weight loss.
As discussed in the first article of this series, ketosis is a metabolic state in which the brain switches to using ketone bodies – derived from the breakdown of fat – as its primary energy source, instead of glucose. This way body protein, which would otherwise be broken down and converted into glucose through the process of gluconeogenesis, are spared.
Over 8–10 mmol/l: It’s normally impossible to get to this level just by eating a keto diet. It means that something is wrong. The most common cause by far is type 1 diabetes, with severe lack of insulin. Symptoms include feeling very sick with nausea, vomiting, abdominal pain and confusion. The possible end result, ketoacidosis, may be fatal and requires immediate medical care. Learn more
In the mid-1990s, Hollywood producer Jim Abrahams, whose son's severe epilepsy was effectively controlled by the diet, created the Charlie Foundation to promote it. Publicity included an appearance on NBC's Dateline programme and ...First Do No Harm (1997), a made-for-television film starring Meryl Streep. The foundation sponsored a multicentre research study, the results of which—announced in 1996—marked the beginning of renewed scientific interest in the diet.[1]

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]
Ketoacidosis, on the other hand, is dangerous. But it’s usually limited to people with type 1 diabetes, striking when their glucose levels rise due to illness or a missed insulin dose. Without insulin, cells can’t take in glucose, so they burn fat for fuel instead, producing exceptionally high ketone levels—much higher than the amount generated by the keto diet. That, in combination with high blood glucose levels, essentially poisons the blood. “It’s very easy to tell the difference between nutritional ketosis, which has no negative symptoms [aside from ‘keto breath,’ which can smell like nail polish remover], and dietary ketoacidosis, which is an illness that requires hospitalization and causes lethargy, abdominal pain, nausea, vomiting, rapid breathing, and lack of appetite,” says William Yancy, MD, program director at the Duke Diet and Fitness Center in Durham, North Carolina.
The past 4 years I was suffering from mild to severe pain all over my body and unrelenting fatigue, sleep disturbances, brain fog, etc. Diagnosed with Sjogren’s Syndrome and Fibromyalgia. Medication included Vicodin, Morphine and a muscle relaxer. I would not take Plaquenall (spelling?), Lyrica or other “biologics”. I was taking a bunch of supplements but nothing was improving.  
These chewy cookies take the same amount of prep and ingredients compared to dirty keto cookies — and the results are packed with nutrients and rich flavor. With a dough made out of almond meal, gut-loving collagen protein, cocoa powder, and melty chunks of dark chocolate, this recipe bakes up into a sinful-tasting dessert with benefits. Just 2.5 net carbs per cookie.

A study with an intent-to-treat prospective design was published in 1998 by a team from the Johns Hopkins Hospital[20] and followed-up by a report published in 2001.[21] As with most studies of the ketogenic diet, no control group (patients who did not receive the treatment) was used. The study enrolled 150 children. After three months, 83% of them were still on the diet, 26% had experienced a good reduction in seizures, 31% had had an excellent reduction, and 3% were seizure-free.[Note 7] At 12 months, 55% were still on the diet, 23% had a good response, 20% had an excellent response, and 7% were seizure-free. Those who had discontinued the diet by this stage did so because it was ineffective, too restrictive, or due to illness, and most of those who remained were benefiting from it. The percentage of those still on the diet at two, three, and four years was 39%, 20%, and 12%, respectively. During this period, the most common reason for discontinuing the diet was because the children had become seizure-free or significantly better. At four years, 16% of the original 150 children had a good reduction in seizure frequency, 14% had an excellent reduction, and 13% were seizure-free, though these figures include many who were no longer on the diet. Those remaining on the diet after this duration were typically not seizure-free, but had had an excellent response.[21][22]
These affect your brain and spine, as well as the nerves that link them together. Epilepsy is one, but others may be helped by a ketogenic diet as well, including Alzheimer’s disease, Parkinson’s disease, and sleep disorders. Scientists aren’t sure why, but it may be that the ketones your body makes when it breaks down fat for energy help protect your brain cells from damage.
I tried the keto diet a couple years ago and about 6 weeks in of following it closely I started having significant episodes of lightheadedness and anxiety like symptoms. The coach I was working with said it was keto flu so I continued on the diet for a couple more weeks but it was making life difficult so I stopped. Now every time I try to go low carb the symptoms come back. Sometimes I wonder if it’s just anxiety response or all in my head. I would love to eat low carb but haven’t ever been able to figure out why this happens. I read somewhere that keto can be harder for women’s bodies and affect their adrenal glands. Would this increase anxiety symptoms.
The ketogenic diet is not a benign, holistic, or natural treatment for epilepsy; as with any serious medical therapy, complications may result.[28] These are generally less severe and less frequent than with anticonvulsant medication or surgery.[28] Common but easily treatable short-term side effects include constipation, low-grade acidosis, and hypoglycaemia if an initial fast is undertaken. Raised levels of lipids in the blood affect up to 60% of children[38] and cholesterol levels may increase by around 30%.[28] This can be treated by changes to the fat content of the diet, such as from saturated fats towards polyunsaturated fats, and if persistent, by lowering the ketogenic ratio.[38] Supplements are necessary to counter the dietary deficiency of many micronutrients.[18]

Physicians of ancient Greece treated diseases, including epilepsy, by altering their patients' diet. An early treatise in the Hippocratic Corpus, On the Sacred Disease, covers the disease; it dates from c. 400 BC. Its author argued against the prevailing view that epilepsy was supernatural in origin and cure, and proposed that dietary therapy had a rational and physical basis.[Note 3] In the same collection, the author of Epidemics describes the case of a man whose epilepsy is cured as quickly as it had appeared, through complete abstinence of food and drink.[Note 4] The royal physician Erasistratus declared, "One inclining to epilepsy should be made to fast without mercy and be put on short rations."[Note 5] Galen believed an "attenuating diet"[Note 6] might afford a cure in mild cases and be helpful in others.[11]


First appointment: Your first meeting with our team will be a one-hour new patient appointment. You’ll meet our nurse practitioners, social worker and dietitians to discuss the diet’s daily requirements, the initiation process, the length of time your child will be on the diet, how the diet may affect your family and any other questions your family may have. If the ketogenic diet team and your family both agree the diet will be manageable for your family, an initiation is scheduled.

I’m following the ketogenic diet and I find it very easy, pleasant and varied. I can even say that my diet today is more varied than the previous one. I do not intend to leave this diet and I cannot really see why. My initial focus was not to lose weight, I’ve always been lean, but to feel better, well disposed. And I got it! I am very pleased, I have read a lot about it (including scientific literature) and I have influenced other people who need to lose weight or improve some aspects of their health. But from the beginning I went on my own way, without the help of a nutritionist because I did not want to suffer the influence of others’ ideas.


Modern-day ketogenic diet promoters such as Pete Evans advocate low-carbohydrate diets for babies and children. However, the Inuit practiced exclusive breastfeeding until their children reached 2 years of age,[11] at which time meat was introduced in their diets. In other words, at the time of most rapid brain growth, the low-carb eating Inuit provided their children with the only carbohydrate-rich food available to them – human milk.
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]
Be aware of the effects of nightshades on your body; while they are permitted in ketosis, they cause inflammatory diseases like rheumatoid arthritis in sensitive people. Nightshades include tomatoes, tomatillos, peppers, okra, and eggplant. For a Bulletproof ketosis, also limit onions and garlic, which tend to be moldy and can disrupt your alpha brain waves. Plus, lightly cook any oxalate-heavy cruciferous and leafy greens.[1]
If you think you may have a medical emergency, call your healthcare provider or 911 immediately. Any mention of products or services is not meant as a guarantee, endorsement, or recommendation of the products, services, or companies. Reliance on any information provided is solely at your own risk. Please discuss any options with your healthcare provider.
You won’t miss dirty keto add-ins like heavy cream or peanut butter with this recipe. Ripe strawberries and coconut milk blend into a sweet pastel shake perfect for dessert (or breakfast). Choose full-fat canned coconut milk for your dairy and get fresh, organic strawberries to make it more Bulletproof. (And enjoy chia seeds in moderation, since they can irritate your stomach.)

Around this time, Bernarr Macfadden, an American exponent of physical culture, popularised the use of fasting to restore health. His disciple, the osteopathic physician Dr. Hugh William Conklin of Battle Creek, Michigan, began to treat his epilepsy patients by recommending fasting. Conklin conjectured that epileptic seizures were caused when a toxin, secreted from the Peyer's patches in the intestines, was discharged into the bloodstream. He recommended a fast lasting 18 to 25 days to allow this toxin to dissipate. Conklin probably treated hundreds of epilepsy patients with his "water diet" and boasted of a 90% cure rate in children, falling to 50% in adults. Later analysis of Conklin's case records showed 20% of his patients achieved freedom from seizures and 50% had some improvement.[10]

When you eat less than 50 grams of carbs a day, your body eventually runs out of fuel (blood sugar) it can use quickly. This typically takes 3 to 4 days. Then you’ll start to break down protein and fat for energy, which can make you lose weight. This is called ketosis. It's important to note that the ketogenic diet is a short term diet that's focussed on weight loss rather than the pursuit of health benefits. 
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