Does the Ketogenic Diet Actually Work?

I get that fats are good for you—but I recently read something about a magical diet that involves basically eating only fat, which supposedly helps you burn way more calories and lose weight. It sounds like real life equivalent of Kalteen bars—way too good to be true. Is the ketogenic diet legit? Should I try it? —Joseph H.

So, you’re thinking about trying the ketogenic diet? Let’s dive into all the details and go over the pros and cons!

About the Ketogenic Diet

The diet gets its name from a fat-burning metabolic state called ketosis. Basically, when you drastically reduce your intake of carbohydrates, your body is forced to use fat as fuel instead of its preferred energy source, glucose. Burning through excess fat for energy produces these compounds called ketones. When you start producing ketones, you’re officially in ketosis, or “fat-burning” mode. (Note: ketosis is not the same as ketoacidosis, a dangerous metabolic condition that can be fatal if left untreated.)

Ketogenic Diet and Weight Loss

The funny thing is that the ketogenic diet wasn’t initially meant for weight loss. I first learned about it after I was diagnosed with epilepsy, while researching drug-free treatments. In the 1920s, before modern advancements in anticonvulsant drugs, neurologists found that epilepsy patients who tried fasting drastically reduced their number of daily seizures. But fasting all day every day wasn’t practical—so they developed a very low-carb, high-fat diet that was meant to be easier to follow while still producing ketones.

That’s when researchers discovered an interesting side effect that had nothing to do with reducing seizure activity: patients started burning fat like crazy. The goal was to take in about 75 percent fat, 20 percent protein, and about 5 percent carbs. When you eat this way for long enough—roughly five to seven days—you’ll find yourself in ketosis.

Although benefits may include weight loss, decreases in body fat, lower blood pressure, and even clearer skin, it’s not for the faint of heart. On a typical ketogenic diet, you’re limited to about 50 grams of carbohydrates a day. That’s less than the carbs in two slices of bread. ALL. DAY. If you eat more than that, you’ll knock your body out of ketosis—which means you can wave goodbye to fat-burning.

That pretty much limits your diet to dietary fats and proteins, with few veggies and zero fruits. This can lead to mineral and vitamin deficiencies, fatigue, and constipation—not to mention, it’s a little less than inspiring.

OK, we’ve established that the ketogenic diet does indeed burn fat. So should you try it? If you clear it with your doctor and can stick to a strictly low-carb lifestyle, it might work for you. However, the ketogenic diet is pretty extreme, and you should make sure you’re checking in regularly with your MD if you’re planning  to try it for more than a few weeks at a time.

Keto-Friendly Recipes

Mustard Roast Beef
Looking for the ultimate Sunday supper? Look no further! This impressive meal is actually a snap to put together, and it’s perfect for a crowd.

Kale-Hemp Pesto
More rich and hearty than basil pesto, this kale-hemp version has a mild flavor that works beautifully on everything from pasta to roasted veggies. And, between omega-3s in the hemp seeds and antioxidants in the kale, it’s extra wholesome. To make it vegan, swap out the parmesan for nutritional yeast.

Coconut Creamed Spinach With Eggs
A little fancier than scrambled, but easier to pull off than poached, baked eggs come out just right: runny golden yolks surrounded by firm whites. Nestled into a skillet full of dairy-free coconut creamed spinach, they’re all but irresistible—either for a Sunday brunch or a quick weeknight dinner.

Lamb Burgers With Pistachio Pesto
This recipe comes from The Primal Kitchen Cookbook, written by PK founder Mark Sisson. It’s filled with everything from simple sauces and smoothies to crave-worthy meals like loaded potato wedges, honey mustard salmon, and these flavorful lamb burgers with a vibrant pesto—keto, Paleo, and Whole30Ⓡ-approved.

Roasted Salmon and Cauliflower Rice Bowl
Mild in flavor and color, cauliflower makes an ideal substitute for rice in grain-free cooking. Here, we’re using it as a base for a roasted salmon and sautéed veggies, and amping the flavor up with traditional Middle Eastern spices.

For more, check out our ultimate guide to the keto diet!

Photo credit: Alicia Cho