The ketogenic diet (often referred to as “going keto” by enthusiasts) may be the latest fad your diet-obsessed friends are currently professing their love for, but it’s actually been around for decades. It’s well known among health professionals as part of some treatment plans for children with epilepsy, given its ability to help prevent seizures in about 50 percent of cases. More recently it’s been gaining traction as both a weight-loss diet and a way to improve sports performance. However, most dietitians and other health professionals don’t recommend it for either scenario.
Beyond the fact that this diet is extremely difficult to follow, it’s not good for our health or the health of the planet. By eliminating fruits, most vegetables, grains, legumes, and most dairy, you miss out on key health-promoting nutrients.
Although it’s marketed as a high-fat, low-carb diet (very trendy these days), it’s more extreme than most of the high-fat diets in that a person must eat about 75 to 80 percent of calories from fat, 15 to 20 percent from protein, and less than 5 percent from carbohydrates. For most people this means eating no more than 1 cup of pasta or two bananas per day, and that’s only if all other sources of carbohydrates are otherwise avoided. So, fruits, grains, many vegetables, and legumes are off limits (as is anything with sugar or refined carbohydrates and alcohol) and dairy must be very limited. Instead, those following the ketogenic diet can eat oils, butter, avocado, eggs, small amounts of full-fat dairy, poultry, leafy greens, fish, beef, and nuts or seeds (in limited quantities, as they do have some carbohydrates).
What’s the goal? Carbohydrates, which are broken down into glucose, are the main source of energy for our bodies (especially the brain), but when the body is starved of carbohydrates it turns to other sources of fuel – in this case fat. When fat is the primary fuel source, a byproduct called ketones is created (putting the body into what’s called ketosis), hence the name “ketogenic diet.” To stay in ketosis (which is the purpose of this diet, so that the body burns fat for energy), it’s mostly about eating fat — even too much protein can lead the body to create glucose from the protein.
Beyond the fact that this diet is extremely difficult to follow, it’s not good for our health or the health of the planet. By eliminating fruits, most vegetables, grains, legumes, and most dairy, you miss out on key health-promoting nutrients. Taking a multivitamin can help with some missing vitamins and minerals, but it doesn’t provide all of the phytonutrients and fiber that plant foods do (a reason that many complain of stomach troubles on this diet). We also know that diets high in animal products (especially saturated fat) and low in plant foods are also linked with many health conditions including heart disease, diabetes, and some cancers. Not to mention the environmental impacts of eating a diet that is mostly animal products.
Outside of very specific clinical settings, the ketogenic diet doesn’t have a place in most healthy people’s lives. Instead of going to such extremes, reducing refined carbohydrates, eating more healthy fats, and filling up on plant foods will set you on a path to long-term health.
As a weight-loss tool, it may appear to work in the short term for some. People initially see a quick loss of a few pounds, but the loss is primarily due to lost water weight from cutting back on carbohydrates (our bodies store water with carbohydrates), so the pounds will be regained as soon as carbohydrates are added back into the diet. Those who are able to stay with the plan for longer than a week or two (the semi-seductive idea of eating butter, butter, and more butter may sound appealing to some, but it’s not an easy diet to follow) may continue to lose some weight if total calories consumed are reduced — not a unique characteristic to the ketogenic diet. Research suggests that people report feeling fatigued, weak, and even nauseous in the first few weeks of following the diet, so compliance is a big issue. As with most diets, though, weight is regained with the return to “normal” eating (or the pre-keto diet). This is not meant to be a lifelong diet — even for children with epilepsy.
Athletes like LeBron James and Ironman Dave Scott (six-time winner of Kona World Championships) have brought interest in the ketogenic diet to the athletic community. Proponents believe that following a ketogenic diet can train the body to tap into fat stores instead of requiring carbohydrates (our muscle’s preferred fuel source during exercise, especially for endurance training). While there is some truth to the idea of adaptation, research shows that carbohydrates are the limiting factor in determining how far and fast athletes can go (both in both endurance activities and in shorter bursts), so it’s not a good idea for most. In fact, it takes more oxygen (meaning you have to work harder) to use fat for energy than carbohydrates, and research has shown that it can take months for the body to adapt to using ketones for energy, leaving even highly trained athletes feeling sluggish and reducing performance for long periods of time.
Outside of very specific clinical settings, the ketogenic diet doesn’t have a place in most healthy people’s lives. Instead of going to such extremes, reducing refined carbohydrates, eating more healthy fats (such as olive oil, nuts, seeds, and fatty fish), and filling up on plant foods like fruits, vegetables, whole grains, and legumes will set you on a path to long-term health.
At Bon Appétit, we know there’s a lot on your plate that you worry about. That’s why we have a team of registered dietitian nutritionists ready to answer your nutrition questions about which food choices will help you avoid unwanted pounds, work or study (and sleep!) better, and form long-lasting healthy eating habits. Email your questions and feedback to nutrition@cafebonappetit.com.