The alluring promise of the keto diet, potentially filled with as much bacon, butter, eggs, and avocado as you can eat, sounds like the grown-up version of scoring a golden ticket to Willy Wonka’s Chocolate Factory. I mean, who wouldn’t want to chow down on bacon and butter at every meal? Especially if you ended up dropping a few pounds along the way?
The catch, of course, is that if it sounds too good to be true, it probably is. And that’s exactly what hopeful dieters need to keep in mind when approaching the ketogenic diet (if we're calling it by its formal name). It’s not that this high-fat, moderate-protein, low-carbohydrate approach to eating can’t deliver weight loss in a delicious package, but it’s a restrictive, sometimes complicated affair that isn’t sustainable for most people.
The basic science behind the keto diet
To understand what the keto diet is, you have to understand a little about how your body generates and uses energy for daily activity. All day, every day, your body undertakes a series of chemical processes (together referred to as metabolism) to break down and use a combination of carbohydrates and fats to produce energy. The energy produced is used for everything -- from breathing to brushing your teeth to running to catch a taxi. Your body is burning fuel constantly just to sustain basic life function. And while your body is always burning a combination of fats and carbohydrates, your brain’s primary fuel source is carbohydrates… and your brain requires a surprising amount of energy to get you through each day.
When carbohydrate consumption is limited, your body has to use an alternate fuel source to keep your brain going. This is the general premise behind the ketogenic diet. “The ketogenic diet is a high fat diet with low carbohydrate and moderate protein content,” says Gabrielle Mancella, a Registered Dietitian with Orlando Health. “Carbohydrate is depleted to provide an alternative fuel source, known as ketones, to the brain. The body converts from burning carbohydrates to burning fats, known as ketosis.”
The catch? The extreme nature of the carbohydrate restriction required to enter ketosis. Mancella explains that the traditional ketogenic diet consists of a daily calorie intake of roughly 90% fat, 6% protein, and 4% carbohydrate, while a slightly more moderate approach to the diet might consist of 80% fat, 15% protein, and 4% carbohydrate.
In either case, think about that for a second: Mancella says a 4% carbohydrate consumption translates to roughly 20-50 grams of carbs per day. And given that a single cup of cooked pasta contains roughly 45-grams of carbs by itself, and a single English muffin has about 30-grams of carbs, a single, poorly-planned meal could undo your efforts to achieve and maintain ketosis in a hurry.
And that’s the kicker -- most people “going keto,” may not actually be following a true ketogenic diet since it’s hard to know for sure if your body’s in ketosis. Mancella explains that the only formal and valid method of determining if your body is in ketosis is if there are ketone bodies being excreted in your urine. “There are strips for purchase at local drug stores that are available to determine this,” she says. “Otherwise, we’re not actually sure if we’re in ketosis, and we’re just following a ‘low carbohydrate’ diet.”