On the ketogenic diet, carbohydrates are restricted and so cannot provide for all the metabolic needs of the body. Instead, fatty acids are used as the major source of fuel. These are used through fatty-acid oxidation in the cell's mitochondria (the energy-producing parts of the cell). Humans can convert some amino acids into glucose by a process called gluconeogenesis, but cannot do this by using fatty acids.[57] Since amino acids are needed to make proteins, which are essential for growth and repair of body tissues, these cannot be used only to produce glucose. This could pose a problem for the brain, since it is normally fuelled solely by glucose, and most fatty acids do not cross the blood–brain barrier. However, the liver can use long-chain fatty acids to synthesise the three ketone bodies β-hydroxybutyrate, acetoacetate and acetone. These ketone bodies enter the brain and partially substitute for blood glucose as a source of energy.[56]

Metagenics offers a wide range of educational opportunities including webinars, group meetings, and seminars as part of our commitment to continuing functional medicine education. Our goal is to give our practitioners further insight to help address their patients’ unique health needs for a higher level of personalized, lifetime wellness care. We have been sharing this ever-growing body of nutritional and lifestyle research for over 25 years.
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.

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.
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 >

Despite its explosive popularity, there’s a lot of confusion about what the ketogenic (keto) diet really is. “Many people think they’re following a keto diet when they’re really just consuming a low-carbohydrate diet,” says Patti Urbanski, MEd, RD, CDE, a certified diabetes educator with St. Luke’s Hospital in Duluth, Minnesota. “So one person’s ‘keto diet’ may look very different than another’s.”
Some sugar-free candy may seem safe (especially on dirty keto), but can contain the wrong sugar alcohols that could spike your blood glucose. This recipe uses stevia, which ranks much lower on the glycemic index, combined with lemon juice and gelatin for a chewy 3-ingredient gummy candy that still satisfies your sugar cravings. Make sure your gelatin comes from a pastured source to keep this one Bulletproof.
I was a Corpsman (not a corpse-man as some recent somewhat fanatical president would say), and I can tell you many stories of Marines and Sailors who maintained restrictive diets (aka picky eaters). Most obvious was lack of sustaining energy (hypoglycemia) at mile 15 (with 80lbs of gear including a 6.5lb rifle and 200 rnds of ammo, etc.) and depletion of essential vitamins, electrolyte imbalance. They were always the first to collapse and have to hear me scold “see I told you so.” An IV of D5W usually does the trick (D is for dextrose, OMG!)
People use a ketogenic diet most often to lose weight, but it can help manage certain medical conditions, like epilepsy, too. It also may help people with heart disease, certain brain diseases, and even acne, but there needs to be more research in those areas. Talk with your doctor first to find out if it’s safe for you to try a ketogenic diet, especially if you have type 1 diabetes.
Professional guidance is important in deciding whether or not the ketogenic diet is the right path based on the individual’s health history and goals, and it's also necessary to routinely monitor ketone levels in the body while on the diet. At Metagenics, we offer a number of resources to help support the ketogenic journey along with several convenient ketogenic supplementation options to help bring convenience and variety to ketogenic living.

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.
On your keto food list, stick to low-glycemic sweeteners to avoid spikes in blood sugar, and avoid fillers and binders such as maltodextrin and dextrose, which can spike blood sugar and contain sneaky carbs. Sugar alcohols such as maltitol or xylitol may read as no sugar on a label, but be aware that they will still cause moderate glycemic response when digested.

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 an advanced nutritional approach that improves fat burning, preserves lean body tissue and improves brain function. The Ketogenic diet also starves cancer cells of their preferred fuel source (sugar) and allows our immune system to function at it peak. This book goes over all the details and challenges involved with the Ketogenic diet in order to turn your body into a lean, mean fat burning machine. You will find invaluable information in this 10 chapter E-guide that will help you break through challenges you have experienced in the past with the ketogenic diet.
Reduced hunger. Many people experience a marked reduction in hunger on a keto diet. This may be caused by an increased ability of the body to be fueled by its fat stores. Many people feel great when they eat just once or twice a day, and may automatically end up doing a form of intermittent fasting. This saves time and money, while also speeding up weight loss.
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