In essence, it is a diet that causes the body to release ketones into the bloodstream. Most cells prefer to use blood sugar, which comes from carbohydrates, as the body’s main source of energy. In the absence of circulating blood sugar from food, we start breaking down stored fat into molecules called ketone bodies (the process is called ketosis). Once you reach ketosis, most cells will use ketone bodies to generate energy until we start eating carbohydrates again. The shift, from using circulating glucose to breaking down stored fat as a source of energy, usually happens over two to four days of eating fewer than 20 to 50 grams of carbohydrates per day. Keep in mind that this is a highly individualized process, and some people need a more restricted diet to start producing enough ketones.
The classic ketogenic diet is not a balanced diet and only contains tiny portions of fresh fruit and vegetables, fortified cereals, and calcium-rich foods. In particular, the B vitamins, calcium, and vitamin D must be artificially supplemented. This is achieved by taking two sugar-free supplements designed for the patient's age: a multivitamin with minerals and calcium with vitamin D.[18] A typical day of food for a child on a 4:1 ratio, 1,500 kcal (6,300 kJ) ketogenic diet comprises three small meals and three small snacks:[28]
I actually went on a ketogenic diet last year to see if it would help my migraines. I have a history of chronic migraines which would usually last 3 days, sometimes longer. Triptans help a lot but I don’t like having to take them. I stayed in ketosis for about 8 months and experienced a significant reduction in migraines, from feeling some type of headache (mild o r severe) almost everyday to 1 or 2x per month while in ketosis. Although I’m very healthy otherwise, I do think my migraines may have something to do with blood sugar fluctuations (despite previously eating a whole foods diet and no refined carbs), and keto totally stabilized this. I eventually came off of Keto because I’m not really a meat lover. When I came off, but remained low carb, my migraines stayed under control for the most part. When I increase carbs, they do return.

The ketogenic diet is a mainstream dietary therapy that was developed to reproduce the success and remove the limitations of the non-mainstream use of fasting to treat epilepsy.[Note 2] Although popular in the 1920s and '30s, it was largely abandoned in favour of new anticonvulsant drugs.[1] Most individuals with epilepsy can successfully control their seizures with medication. However, 20–30% fail to achieve such control despite trying a number of different drugs.[9] For this group, and for children in particular, the diet has once again found a role in epilepsy management.[1][10]

If you’re wondering about the difference between ketosis and diabetic ketoacidosis, you’re not alone. “The word ketone is scary for most people with type 1 diabetes because they relate ketones to diabetic ketoacidosis,” says Patti Urbanski, MEd, RD, CDE, a certified diabetes educator with St. Luke’s Hospital in Duluth, Minnesota. “But with the ketogenic diet, we’re talking about a much lower level of ketones.”
One of the most-cited worries about the keto diet is the long-term impact it may have on heart health—especially because people with diabetes are at greater risk for heart disease. In the small Diabetic Medicine study that found people with type 1 improved their A1Cs on a keto diet, participants had higher triglycerides and LDL (“bad”) cholesterol. This raises concerns about the diet’s longer-term heart health implications, as do the results of research published last year in The Lancet. That study followed more than 15,000 adults for 25 years and found that people who consumed less than 40 percent of their calories from carbohydrates were significantly more likely to die from heart disease than those whose diets contained 50 to 55 percent of calories from carbs—especially if the foods that replaced those carbs were rich in animal fats and proteins.
The ketogenic diet is a mainstream dietary therapy that was developed to reproduce the success and remove the limitations of the non-mainstream use of fasting to treat epilepsy.[Note 2] Although popular in the 1920s and '30s, it was largely abandoned in favour of new anticonvulsant drugs.[1] Most individuals with epilepsy can successfully control their seizures with medication. However, 20–30% fail to achieve such control despite trying a number of different drugs.[9] For this group, and for children in particular, the diet has once again found a role in epilepsy management.[1][10]
On a ketogenic diet, your entire body switches its fuel supply to run mostly on fat, burning fat 24-7. When insulin levels become very low, fat burning can increase dramatically. It becomes easier to access your fat stores to burn them off. This is great if you’re trying to lose weight, but there are also other less obvious benefits, such as less hunger and a steady supply of energy. This may help keep you alert and focused.
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