Eat fat to burn fat. Sounds crazy, right? But it turns out that ramping up your fat intake — and ditching most carbs — is the quickest, most effective way to lean out. A ketogenic diet was originally developed in the 1920s as a drug-free way to treat epilepsy. Today, it’s taken the fitness world by storm, and with good reason. It can reset your body so that it burns fat — including stored body fat — for energy instead of glucose.
Most Americans chow down on 200-plus grams of carbohydrates every single day. To the body, it doesn’t matter whether these carbs come from sprouted grains and sweet potatoes or pizza and beer. At the end of the day, the body turns all carbs into sugar that is then used for energy. Any sugar that doesn’t get used is converted to glycogen and then turned into fat that is stored for future use. The problem is that when that “future” never comes, you pack on the pounds. Switching to a ketogenic diet, however, creates an environment where the body must rely on fat for energy. But don’t expect instant karma. Becoming fat-adapted can take several weeks. During the process, your liver creates ketones that break down fat so it can be used for energy. That means when you are in ketosis, you become an efficient fat-burning machine.
Science Says . . .
Unlike many trendy diets, the ketogenic diet is backed by science. One study, for example, compared the impact of a ketogenic diet to a low-glycemic-index diet on weight loss in 49 obese individuals with Type 2 diabetes. After six months, the group doing keto lost an average of 24.5 pounds, while the low-GI group lost a mere 15.2 pounds. And new research in The Journal of Clinical Endocrinology & Metabolism found that the weight loss on a keto diet is mainly body fat, including visceral fat.
Keeping yourself in ketosis can be especially beneficial if you take part in endurance events. In a clinical trial of 20 elite endurance athletes, researchers at Ohio State University were surprised to find that those eating a ketogenic diet burned more than twice as much fat as their high-carb counterparts during maximum exertion and prolonged exercise. So if you’re gearing up for a Spartan race or other endurance or obstacle event, forget carb loading and opt for keto!
About now you might be thinking that keto sounds too good to be true. After all, can a steady diet of butter and bacon really be heart healthy? Yes, it can! A recent meta-analysis of 13 randomized-control trials reported that long-term keto dieters not only lost more weight, but they also experienced improved triglycerides, high-density lipoprotein (HDL) cholesterol and blood pressure compared to those on a low-fat diet.
Ready to jettison the carbs? Here’s what you need to know. When you’re on a ketogenic diet, at least 70 (yes, 70!) percent of your daily calories come from fat. Twenty percent comes from high-quality animal protein. The remaining 10 percent is allotted to carbs (20 to 50 grams per day). That may sound counterintuitive to conventional wisdom, but redistributing your macronutrients works — and it definitely has its perks:
No calorie counting! So long as you keep your carb intake low, you shouldn’t have to worry about calories.
Less hunger. Research suggests that the production of ketone bodies lowers your levels of the hunger hormone ghrelin. Because ketones have a damping effect on appetite, most people spontaneously reduce their food intake when they eat a high-fat diet.
Fast initial weight loss. When you first limit carbs, your body uses the glycogen in your muscles and liver. This also causes rapid water weight loss during your first week or two as you fully transition into ketosis. As a result, you may be more motivated to stick with keto.
Know When You’re in Ketosis
One type of ketone produced during ketosis is acetone, and it can’t be used by the body. Instead, acetone is excreted as waste, mostly in the urine and the breath. That makes it easy to tell if you’re in ketosis.
While changes to your breath can be an indication, a more accurate way to verify ketosis is with ketone urine testing strips. Simply pass the test end of the strip directly through your urine stream. Shake off any excess, then wait 15 seconds. If you’re in ketosis, the strip will change color from its original beige to purple.
Studies suggest that the best time to test for urinary ketosis is when you first get up in the morning. That’s because ketosis is at its highest level and can be more reliably detected. Alternatively, you also can get a good reading right after dinner.
Over time, most long-term keto’ers find that once they’ve reached their ideal weight and body-fat percentage, they can increase their carbs and still stay in ketosis. But since everyone is different, testing can help you determine your maximum carb intake before you are kicked out of your fat-burning mode.