Though it was originally developed to treat patients with epilepsy, interest in the ketogenic diet has taken off in recent years as we've learned more about its therapeutic and health benefits. Here’s what you need to know about ‘keto’ and why some health experts believe it's good for your body — especially your brain.
Fasting and other ketogenic-like diets have been used to treat conditions like epilepsy for thousands of years. And in fact, a version of the keto diet has been traced back to 500 BC.
Fast forwarding a bit, Dr. Rawle Geyelin gave a 1921 presentation to the American Medical Association in which he reported on the remarkable outcomes of several children who had benefited from fasting; his patients were having fewer seizures — and the effect appeared to be long-lasting.
Geyelin continued this work, and he developed a tolerable and reproducible high-fat and low carbohydrate diet now formally known as the ketogenic diet. For the next two decades, it was used by physicians to minimize seizures in their patients. Once modern antiepileptic drugs were introduced, however, the practice declined dramatically.
But interest in keto was renewed about 20 years ago as a number of scientists began to study it more closely — and not just for its ability to treat epilepsy. As we’re now learning, and despite its reputation as a “starvation” diet, a keto regimen has been shown to confer a variety of benefits.
The state of ketosis
The ketogenic diet is essentially a way to get our bodies to enter into a condition known as ketosis.
Normally, our bodies rely on glucose for fuel — the result of our moderate to high-carb diets. Carbohydrates are broken down to glucose, which gets converted into energy and transported to our muscles and organs.
But when carbs are restricted, and when there’s a lack of glucose, our liver starts to produce ketones — a process that shifts our body towards fat utilization. This new mode of metabolism, or ketosis, can come about in several different ways, including starvation, type 1 diabetes, and even alcoholism.
While in this state, the levels of ketones in our blood starts to rise. Ketones are acidic chemicals that include acetone, acetoacetate, and beta-hydroxybutyrate. Needless to say, this can lead to some serious problems; starvation is obviously not good! If left unchecked, ketones can increase blood acidity, which can affect urine and cause serious liver and kidney damage.
But, when done correctly and responsibly, the keto diet can be used to effectively treat a number of health conditions.
Image: "Alterations in intermediary metabolism during the high-fat, low-carbohydrate ketogenic diet that lead to the formation of ketone bodies. The ketogenic diet provides high levels of long chain fatty acids and is deficient in carbohydrates so that glucose availability is severely limited." Source.
How to do keto
A keto diet can take on many forms, but it typically involves the restriction of carbohydrates to no more than 50g per day. Sources should typically come from whole foods like vegetables, nuts, dairy, and so on. Refined carbohydrates, like bagels, pasta, and cereals, should be avoided, as should refined sugars (including high-sugar fruits and fruit juices).
Meals, therefore, should mostly be comprised of protein and some healthy fats (like olive oil, coconut oil, and avocados). A good rule of thumb is to follow the 60/35/5 rule in which 60% of calories come from fat, 35% from protein, and 5% from carbs. Protein should be set at about 1.5 to 1.75g of protein for every kilogram of your ideal body weight.
For comparison, a typical Western diet is about 5-15% protein, 10-20 % fat, and 65-85% carbohydrates.
It’s also important to not overdo the protein; a high-protein diet may prevent the body from entering into ketosis. Also, this is not a form of intermittent fasting — that's something else.
The UNM School of Medicine offers this dietary advice:
As examples, a typical meal might include some type of meat with green vegetables cooked with a mayonnaise sauce or a lot of butter. Heavy cream may be included on the side for drinking. Another meal might consist of bacon and eggs with a lot of butter or oil added, and heavy cream to drink. A very high ratio of fats to carbohydrates must be maintained with a low total calorie intake for the diet to be successful.
Lacto-ovo vegetarians can hit up the cheese, eggs, tofu, and low-carb whey protein.
Oh, and if you still think all fats are bad for you — and that they make you fat — read Gary Taubes’s book, Why We Get Fat.
Again, it’s important to stick to these recommendations. And in fact, you should probably talk to your family doctor before going on this diet just to make sure you’re in the clear. Also, you should expect to feel like crap for the first week or two as your body adjusts.
Why it works
Actually, we’re not entirely sure why it works so well. But some theories are beginning to emerge.
Keto diets have beneficial effects in a broad range of neurological disorders, particularly those involving the death of neurons. Scientists think it may have something to do with the effects of cellular energetics.
As already noted, the keto diet is associated with increased circulation of ketones in the body, which is a more efficient fuel for the brain. Ketones may also increase the number of brain mitochondria — the power packs inside of cells.
It’s possible that the boosted energy production capacity created by these effects is what gives our neurons an enhanced ability to resist metabolic challenges. Other biochemical changes — namely ketosis, high fat levels, and low glucose levels — may contribute to neuronal protection through a number of antioxidant and anti-inflammatory actions.
The keto diet is being increasingly considered for the treatment of many neurological diseases and injuries, a list that includes Parkinson’s, Alzheimer’s, stroke, and even traumatic brain injuries. The keto diet can also improve memory function in older adults with increased risk for Alzheimer’s.
Neuroscientists attribute the keto diet’s brain-protective qualities to a number of things:
Ketone bodies serve as an alternative source of energy during metabolic stress
Ketosis diminishes the toxicity produced by glutamate acid, a problem when a brain injury happens
It enhances GABA levels (γ-Aminobutyric acid) — an important inhibitory neurotransmitter
It has antioxidant and anti-inflammatory qualities
The diet protects against various forms of cell death
Restricting carbs protects against oxidative- and glutamate-stress, among other things
As noted, the ketogenic diet was originally meant for the treatment of epilepsy — and it works startlingly well. Research has shown that, for children will refractory epilepsy, a keto treatment lasting for six to 24 months can result in a 90% decrease or elimination of seizures.
Dr. Eric H. Kossoff offers this example of a typical ketogenic meal for a 4-year-old child dealing with epilepsy.
Strangely, the link between ketone bodies and the anticonvulsant effectiveness of the keto diet isn’t clear. Scientists theorize that it has something to do with acetoacetate and acetone, as they’ve been shown to have anticonvulsant properties in animal models.
The keto diet may also help in fighting off certain types of cancer and various tumors. It seems to do a good job treating brain tumors, likely a consequence of its neuroprotective qualities.
In one case, it seems to have helped an elder woman mange her brain tumor. It can also work well in conjunction with radiation therapy to treat brain tumor cells — at least in mice. Some scientists believe that a restricted keto diet is “a viable alternative to the standard care for managing malignant brain cancer.”
A 2011 pilot study indicated that the ketogenic diet is suitable for even advanced cancer patients, claiming that “It has no severe side effects and might improve aspects of quality of life and blood parameters in some patients with advanced metastatic tumors."
The ketogenic diet is also being considered as way to help people lose weight, though evidence of its efficacy and safety are mixed.
A 2006 study comparing ketogenic and non-keto diets concluded that both diets are useful for weight loss, but the researchers found that the keto diet was associated with metabolic and emotional effects. "The use of ketogenic diets for weight loss is not warranted," the authors write.
Another study indicated that keto diets work great for the first three to six months compared to other dietary routines, but that the difference is no longer apparent after a year. The researchers found that keto is associated with favorable changes in triglyceride and HDL cholesterol levels (that’s the good kind), but that it results in higher LDL levels than conventional low-fat diets.
Nancy Krebs’s 2010 study is probably the most favorable in terms of its application to weight loss. Her team concluded that a high-protein, low-carb keto diet may be effective for severely obese adolescents in the long term.
The keto diet has also been used in conjunction with exercise and athletics. And in fact, a growing number of athletes and bodybuilders swear by it, including many CrossFitters and other strength-and-conditioning types.
Formal studies are far-and-few on the subject, but a 2011 Italian study suggested that keto could be used as a way to lose weight in conjunction with exercise.
Because it’s a low-carb diet, ketosis works very well for people with diabetes. It’s effective at improving glycemic control in diabetic patients, and it "has a significant beneficial effect in ameliorating the diabetic state and helping to stabilize hyperglycemia."
Additional reporting by Joseph Bennington-Castro.
Images: Top: Joshua Resnick/Shuttersock; Ketone: Rawle Geyelin/Shutterstock.