What if we told you that indulging in all the butter, cheese, and steak you want can help your energy levels soar, crush cravings, and melt inches off your frame? Well, those are the lofty results the ketogenic (or keto, for short) diet promises—and the actual outcomes aren’t that far off.
Here’s a digestible rundown of how the diet works: Eating no more than 10 percent of your calories from carbs, about 20 percent from protein, and about 70 percent from healthy fats causes the liver to produce ketones, or byproducts of breaking down fat for energy, allowing your body to enter ketosis. (I religiously logged my macros on MyFitnessPal.) Sticking to this low-carb, moderate protein, high-fat diet allows your body to burn fat for fuel rather than glucose—our primary source of energy.
And who doesn’t want that? I sure did, and therefore decided to give it a whirl.
Naysayers swore I’d be irritable, hungry, and wouldn’t last three days. Yet regardless of the doubtful outpouring, my will to enter the magical state of ketosis remained unsullied.
The diet’s long history in science also lends it credibility. Doctors have been prescribing ketogenic diets to treat epilepsy for nearly a century, and increasingly believe it may hold promise for people with Type 2 diabetes.
How the ketogenic diet works
To understand the ketogenic diet, you need a quick primer on how the human body gets energy. We are fueled primarily by glucose, or blood sugar, much of which we derive from carbohydrates in foods like bread, fruit, potatoes, and sweets.
If glucose levels in the blood drop to really low levels, we’d pass out and die. But, interestingly, the body can’t store much glucose — only enough to last a couple of days. So if we forgo eating carbs for a few days, we need other ways to keep going. One of those is a process called ketogenesis.
In ketogenesis, our livers start to break down fat into a usable energy source called ketone bodies, or ketones for short. “Organs like the brain that normally rely primarily on glucose for fuel can begin to use a substantial amount of ketones,” said Kevin Hall, a National Institutes of Health senior investigator who has studied the ketogenic diet. So ketones can stand in for glucose as fuel for the body when there’s a glucose shortage. “It’s an amazing physiological adaption to starvation that allows tissues like the brain to survive,” Hall added.
Once ketogenesis kicks in and ketone levels are elevated, the body is in a state called “ketosis,” where you’re burning stored fat. There are a few ways to get into ketosis. One is through fasting: When you stop eating altogether for an extended period of time, the body will ramp up fat burning for fuel and decrease its use of glucose (which is part of the reason people can survive for as long as 73 days without food
Another way to get into ketosis is by eating less than 20 to 50 grams of carbs — or a slice or two of bread — per day. So people on a ketogenic diet get 5 percent of their calories from carbohydrates, about 15 percent from protein, and 80 percent from fat. Note that that’s a much lower ratio of protein and a lot more fat than you’d get on other low-carb diets, but it’s this ratio that will force the body to derive much of its energy from ketones. If you eat too much protein, or too many carbs, your body will be thrown out of ketosis.
In practice, that means subsisting mainly on meats, eggs, cheese, fish, nuts, butter, oils, and vegetables — and carefully avoiding sugar, bread and other grains, beans, and even fruit. Again, if this sounds familiar, it’s because it’s not that different from the Atkins diet, among the most famous very low-carb diets that promise to get your body burning fat. (Atkins, who reportedly said ketosis is “as delightful as sunshine and sex,” promised to help people “stay thin forever,” the same way the now popular Keto Reset Diet book promises to “burn fat forever.”)
While the evidence behind ketogenic diets for diabetes is still preliminary and the evidence for weight loss proves convincing (more on that next), the evidence of using the diet to treat epilepsy is extremely robust. The idea of treating people with epilepsy with the keto diet came about in the 1920s, when researchers observed that people who fasted experienced fewer seizures. (Researchers still aren’t sure why the diet can work for epilepsy, but a few mechanisms have been proposed, including making neurons more resilient during seizures.)
Today, studies have shown that children and adults whose epilepsy doesn’t respond to medications seem to experience a pretty large reduction in seizures when following a ketogenic diet. That doesn’t, however, mean that the diet works for other conditions.
The theory behind very low-carb diets is that they help people burn extra calories and fat — and lose more weight
Advocates of ketogenic diets for weight loss claim that ketogenesis can lead to a “metabolic advantage” that helps burn 10 times more fat and an extra 400 to 600 calories per day — the same as a vigorous session of physical activity. The main scientific model that’s used to explain that advantage is the ”carbohydrate-insulin hypothesis,” which has been promoted by experts like Harvard professor David Ludwig, Obesity Code author Jason Fung, journalist Gary Taubes, and pediatric endocrinologist Robert Lustig, among others.
Eating carbs drives up insulin production, the hypothesis suggests, stirring hunger and causing the body to hold on to fat and suppress calorie burn. But when you replace carbs with fat, you subdue hunger, boost calorie burn, and melt away fat. With fewer carbs, your body also doesn’t produce as much insulin — and that increases the rate of ketogenesis and decreases the body’s need for glucose.
So end result is the ketogenic diet can actually make you lose weight.Looking to find out more??
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