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.
Yes, the ketogenic diet works. It’s been scientifically proven to be more effective than low-fat diets for weight loss, and it’s also useful for treating health conditions like diabetes, cancer, and neurological issues like epilepsy and Alzheimer’s. But how it works is a little complicated, and there are some pros and cons to be aware of before trying it.
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.)
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—and you’ll find yourself in ketosis.
The benefits can be impressive: Weight loss, dramatic decreases in body fat, lower blood pressure, and even clearer skin. But 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 a medical professional if you’re going to try it for more than a few weeks at a time. Some studies indicate it could cause hormonal issues for some women, especially female athletes, so consult a doctor if you notice a change in mood, sleep patterns, or your menstrual cycle. If you’re dealing with any serious health issues, it’s always best to get your MD’s approval before beginning a diet regimen.
Photo credit: Alicia Cho