What is the keto diet? Experts break down the popular weight loss diet.

Weight loss and overall health benefits are the two biggest reasons people choose to begin the ketogenic diet, according to recent research.

Over the last few years, the diet known colloquially as "keto" has risen as a popular weight loss mechanism. But is it actually your best bet?

"Restrictive dieting is really unnecessary and usually backfires for most people," registered dietitian Jamie Nadeau tells USA TODAY. "Not only do most people gain weight back after the diet becomes unsustainable, but many end up with disordered behaviors around food. ... It often leaves you feeling like something is wrong with you or that you lack willpower, when really it’s the diet setting you up to fail."

Here's what health experts want you to know about the keto diet.

What is the keto diet?

Originally developed as a diet to treat epilepsy in children, the keto diet has evolved into a popular weight-loss mechanism for adults, Nadeau says.

It's a low-carb diet, but instead of focusing on protein as many others do, it emphasizes consuming higher amounts of fat — and especially saturated fats including butter, lard and palm or coconut oils, according to Harvard Health.

"It puts you into a state called ketosis, which causes your body to burn fat instead of glucose," Nadeau explains.

From a dietitian's perspective, that can be troubling because it de-prioritizes many foods known to have vital nutrients, including whole grains, legumes and fruit, she adds. Health experts also say that diets high in saturated fats are linked to heart disease, and that keto in particular also poses risks including liver and kidney problems, constipation and mood swings.

How fast do you lose weight on keto?

While losing weight quickly is a common goal on diets like keto, Nadeau stresses that it's "quite unsustainable" for most people.

"Even if you initially lose weight, and many do, you’re likely to gain it back when the diet becomes unsustainable," she says. "In fact, many people who initially lose weight on keto end up gaining back the weight they lost plus more."

Harvard Health recommends that if keto is used for weight loss purposes, it's only used as a short-term means to jumpstart the weight loss and not a long-term solution.

If you're looking to lose weight, Nadeau instead recommends focusing on small habit changes: adding more physical activity to your daily schedule, eating more fruits, vegetables and foods high in fiber and protein and drinking more water.

"New diets always sound exciting and it’s easy to get swept up in thinking they’re the magic diet you’ve been searching for," Nadeau says. "The truth, though, is that restrictive diets don’t work long-term. If it’s not something you can envision yourself doing forever, it’s not going to work. Your diet changes should be things you can fit into your life forever so that you can maintain your health and results forever."

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