Understanding the Ketogenic Diet - A Dietitian's take on "Going Keto"'
The Ketogenic Diet was one of the top Googled diets in 2017, according to Time magazine. If you follow #fitspo on social media or eavesdrop on conversations at your gym, it’s likely that you’ve encountered someone who is following the “Keto” Diet or “going keto.” Maybe you have even considered trying it for yourself.
Adopting the Keto Diet involves drastically reducing your carbohydrate intake to 15-30 grams per day. For reference, that’s about one small banana. The remainder of The Keto Diet consists mostly of meats, fish, eggs, cheese, butter, oils, creams, green leafy vegetables, and nuts. Breads, pasta, flour, rice, beans, potatoes, and fruits are eliminated completely.
Why would anyone voluntarily subject themselves to such torture? Well, unlike Whole30 and Weight Watchers, The Ketogenic Diet was not initiated by a commercial company or a social media influencer; it first gained attention from the medical community. A growing body of research suggests that the Keto Diet can reduce seizures in children with epilepsy and that over half of children who go on the diet have seen at least a 50% reduction in seizures (1). The mechanism of this is not entirely clear, but the most supported theory is related to a process known as ketosis (hence “keto”).
Normally, when we ingest a carbohydrate of any kind, our body breaks it down into glucose. When blood glucose levels rise, our pancreas secretes the hormone insulin. Insulin allows our cells to take in glucose and store it for energy to use later. (NOTE: This is a normal and necessary metabolic process, and glucose is our body’s preferred source of fuel). Ketosis is a process that occurs when there is not enough glucose in the blood (due to lack of carbohydrate intake). Fat stores are broken down into ketones, which are used as a alternative source of energy. Under normal circumstances, glucose is the brain’s primary source of energy. Therefore, ketosis naturally alters energy metabolism in the brain. This is thought to suppress the rapid firing of nerve cells that occurs during seizures.
Medical professionals and parents of children with epilepsy aim to reduce the obstacles associated with seizures, and are usually willing to take on the risks of such a restrictive diet if it is in the best interest of their child’s physical and mental safety. But are there benefits of adopting the Keto Diet for people without epilepsy? And if so, what are the risks?
Fitness and wellness pros that support the Keto Diet claim that the process of ketosis promotes weight loss by breaking down body fat, instead of carbs, for energy. They also claim improved focus and sports performance, and lower cholesterol and triglyceride levels. Yet, these outcomes have only been demonstrated in short-term studies, which is a crucial confounding factor. The longest study that has ever been performed on the Keto Diet in a population without epilepsy is 24-weeks and was conducted on a sample size of only 66 individuals (2). And even if there were more long-term studies conducted, these studies would likely exhibit the serious risks associated with placing such drastic restriction on your carbohydrate intake, including the following:
1. Impaired Brain Function
The brain’s primary fuel source is glucose; it needs a minimum of 140 grams carbohydrates per day to meet this need; that’s equivalent to 3 ¼ cups of cooked pasta just for your brain! When carbohydrate intake is restricted, the body can break down fat and protein for energy, but this is not the preferred method of energy metabolism, and not enough to provide the 140 grams of carbohydrates that the brain requires per day for optimal functioning. Decreased glucose to the brain may be useful for preventing seizures, but for individuals with and without epilepsy, it can lead to poor attention and impaired memory (3, 4).
2. Muscle Atrophy
Since carbohydrate intake is restricted for a long period of time on the Keto Diet, the body resorts to using protein as an alternative source of fuel during exercise. Carbohydrates are normally what powers muscle contraction, but if the individual has consumed more than enough protein (which is usually the case on the Keto Diet), protein stimulates this process when carbohydrates are unavailable. This is a commonly overlooked process; most people assume that fat will be “next in line” for breakdown when there are no carbohydrates, but that is only when there is not adequate protein...which there usually is because muscles can be broken down to get the protein energy. Over time, this makes it extremely difficult to build and maintain muscle mass (5).
3. Metabolic Acidosis (leading to fatigue, confusion, headaches, low bone density)
When the body does actually reach ketosis and metabolize fat (that is: when the body has been meticulously manipulated through rigid control of the diet), carbohydrates are required for the breakdown of the ketones. When carbohydrate intake is restricted, there can be a dangerous buildup of ketones unable to be broken down. This leads to a condition called metabolic acidosis, which causes fatigue, confusion, and headaches. Similarly, metabolites of carbohydrates are also responsible for excreting toxins in the liver. Without this excretion, there is an even higher likelihood of acidosis. To compensate for acidosis, the body may naturally draw calcium from the bones as a buffer, which leads to long-term bone fragility. If that wasn’t bad enough, even short-term studies have shown that buildup of ketones also leads to a buildup of acetone, which induces undesirable side effects like odorous sweat and bad breath (6).
4. Constipation and Digestive Distress
Fiber, which is provided solely by carbohydrate rich foods, is crucial for laxation. This is why constipation is shown to be the most common side effect of the Keto Diet. This effect has been demonstrated in both long-term studies (ten years long) on children with epilepsy and on short-term studies in otherwise healthy individuals. The research upholds that over 60% of individuals who follow the Keto Diet will experience constipation, and this effect will persist long-term. The long-term effects of constipation, apart from discomfort in your stomach, are fatigue, painful hemorrhoids, and compromised immunity (7, 8).
5. Electrolyte Imbalances
Last but not least, restricting the diet in such an extreme way puts Keto Dieters at risk for various deficiencies. Some of the most common are sodium, potassium, and Vitamin D. Sodium controls blood pressure and regulates the function of muscles and nerves and its ability to retain water is also essential to keeping a balance of other electrolytes. Most Keto Dieters will recommend a salt tablet as a supplement to the diet, but supplements will never provide the sustenance and additional nutrients that real foods provide. It is also critical to remember that the Keto diet is overall extremely rigid and not sustainable in an adult population. While it may be possible to get the missing fiber, sodium, potassium, and vitamin D from the foods “allowed” on the Keto Diet, it is not without tasking calculations and persistent tracking of intake. Research focusing on Health at Every Size™ and anti-diet approaches has taught us that restrictions and calculations of food intake leads to emotional distress, food preoccupation, weight cycling and long-term binge eating.
In conclusion, it is also important to note that this diet was never intended for adults. The Keto Diet has been extensively researched and supported for children with epilepsy, but this does not carry over to adult populations with or without seizures. A recent article in Popular Science (link) points out that epilepsy patients on the Keto Diet are always under close supervision of dietitians to make sure that their bodies are not breaking down too much muscle protein into carbohydrate. On the other hand, individuals who take this diet on themselves are running the risk of not actually reaching ketosis and breaking down muscle protein instead….
"It’s not so easy to get an adult body into ketosis," says Teresa Fung, a professor of nutrition at Simmons College. "That’s why the keto diet is used as a treatment of epilepsy in children or infants—because it’s easier." Kids are growing rapidly, she explains, so their use of food as fuel is different from the way adults use it. Researchers aren’t exactly sure what those differences are, but Fung says it's so hard to get adults into deep ketosis (which is likely deeper than a dieter's target) that often nutritionists don't even attempt it as a therapy. It’s primarily kids who undergo the treatment today.”
While there are very few (if any) diets that I endorse, the Keto Diet is definitely not one of them. It’s important to look beyond the shiny selling points like weight loss, ‘fat burning’, and increased athletic performance and also consider the risks associated with the diet, and if the added physical and mental stress is really worth it.
I’d love to hear from you. Leave your comments and questions below and let’s talk more!