And when you’re starving, your body will start to break down protein just to get those sweet, sweet carbs. Of course, you have a source of protein in your body already: your own muscles. “When in starvation mode, your body breaks down muscle in your body,” says Giancoli. “Ketosis is a way of trying to preserve that protein. It’s not ideal, but it’s your body’s way of saving you.”

But the real problem isn’t going over your carb limit—it’s the protein. “If you’re eating a lot of protein, you’re breaking that down into carbs,” Giancoli explains. Your body is in desperation mode on keto, she says, and without a reasonable supply of carbohydrates coming from grains and fruits, you’ll start breaking down the amino acids in proteins to make glucose. Glucose, though it sounds like a scary sugar, is your body’s primary source of fuel. Too much isn’t good for you, but you need some just to allow your cells to function normally.

You’re only allowed 10 to 15 grams of carbohydrates per day, and though many dieters stretch that to more like 20 or 30 grams that’s still only about one banana.

Getting 80-90 percent of your calories from fat—which is what’s required for keto—is actually difficult.

Without getting into true ketosis, dieters risk ingesting an enormous amount of fat—and potentially a lot of saturated fat, if you’re eating animal meat—without any of the fat-burning effects of ketosis.

If you give your body any more than the absolute minimum amount of protein that it needs, it will immediately break it down into carbs. This is why keto sites often give a guideline for not eating too much protein. The problem is that there’s no one guideline that works for everyone, and without specifically tailoring keto to your body it’d be easy to accidentally ingest too much protein.

“Keto is not easy to maintain, it’s not a palatable diet,” says Andrea Giancoli, a dietician and nutrition consultant in California.

The high fat content in the diet, especially if you’re eating saturated fats, can raise your lipid levels and contribute to developing cardiovascular disease.

Of course, ketosis itself comes with its own risks. Circulating ketone bodies make your blood too acidic, and your body will draw calcium from your bones as a buffer.

which only happens when you’re essentially in starvation mode.

likely deeper than the average dieter, but without a nutritionist guiding you it’s still hard to get down into ketosis.

It was supposed to treat severe epilepsy. And as a medical treatment, it was only intended to be administered under the supervision of trained nutritionists and physicians.

So maybe not being in ketosis isn’t so bad after all—now just cut back on the saturated fats.

Without the fiber from whole grains and fruits, you’re also likely to get constipated and have other digestive issues. Plus you need fiber to maintain a health gut microbiome, which tends to come from the kind of whole grains that you can’t eat on the diet.