Both keto critics and advocates explain why there's a right — and wrong — way to do this diet.

By Bethany George/SHAPE.COM
Updated: Feb 27, 2019 @ 11:46 am
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This article originally appeared on Shape. For more stories like it, visit shape.com.

Yep — butter, bacon, and cheese are some of the high-fat foods that you can actually eat while on the keto diet, the country's diet darling of the moment. Sounds too good to be true, right? (Jillian Michaels certainly thinks so.)

Well, it kinda is. Turns out, there's a right way and a wrong way to do the keto diet — which experts have started to call "clean" and "dirty" keto. Here's what you need to know.

How the Keto Diet Works

If you're new to the keto diet, here's the DL: Typically, your body sources most of its fuel from glucose (a sugar molecule found in carbohydrates). However, the keto diet is so low-carb and high-fat — with 65 to 75 percent of your calorie intake from fat, 20 percent from protein, and 5 percent from carbs — that it sends your body into ketosis, a process during which fat is burned for energy rather than glucose. (It takes a few days of eating super-low-carb to enter this state.)

"The keto diet is so popular right now because of its reputation for causing quick fat loss," says Kim Perez, a nutritional therapy practitioner with Kettlebell Kitchen. (Just look at how the keto diet transformed Jen Widerstrom's body in just 17 days.)

However, the source of the fat you eat doesn't necessarily matter when you're trying to lose weight on the keto diet — if you're still in ketosis, it's likely still "working," says Perez. Bacon cheeseburgers, for example, are high in fat and protein and low in carbs, so they don't disrupt your body's state of ketosis. That means that technically they fit the keto diet parameters, and you can still lose weight. (Even though, at this point, it's common knowledge that burgers certainly aren't a health food.)

"Current research doesn't tell us much about the long-term impacts of eating a diet so high in fat," says registered dietitian and Arivale coach Jaclyn Shusterman, R.D.N., C.D., C.N.S.C. (Though initial research hints that the keto diet isn't healthy in the long run.) "One of the important things to remember if you're following a keto diet is that there are healthier—and less healthy—ways to follow this diet," she says.

"To do keto the right way, you should always be supporting your health," says Perez. "At some point, you're going to pay for those foods that you're eating." Enter: the difference between clean and dirty keto.

Clean Keto vs. Dirty Keto — and Why It Matters

Clean keto is like a clean-eating version of the keto diet. It focuses on whole, unprocessed foods that are high in fiber and low in net carbs — but are still packed with other nutrients—such as avocados, green vegetables, coconut oil, and ghee, says Josh Axe, D.N.M., C.N.S., D.C., who's been using the diet for 13 years, and refers to "dirty keto" in his book Keto Diet.

Dirty keto, on the other hand, is following the keto diet and adhering to its carb restrictions without actually steering clear of unhealthy foods. "The dirty keto approach includes lots of meat, butter, bacon, and pre-made/packaged convenience food," says Perez. That also includes seemingly healthy things like protein bars, shakes, and other snacks that boast being sugar-free and low-carb. These foods aren't made with health in mind, because, "when any diets become trendy, companies try to make money off of it by making processed foods [that fit the diet]," says Perez. 

"When people go on diets, they tend to gravitate towards the unhealthy part or asking the question: 'What can I get away with?'" says Axe. "The other day I saw something called 'the ultimate keto recipe' online, and it was taking conventional cheese, frying it in butter, and putting bacon in the middle."

As a long-time advocate of the keto diet, he said the popularity of dirty keto is concerning: "I don't want people to just lose weight; I want people to heal," he says. "Following the principles of the keto diet to get into ketosis can be healing in a lot of ways." Research has looked at the possible links between following a strict keto diet to help manage polycystic ovary syndrome (PCOS), epilepsy, and other neurological diseases.

And, yes, you should care, even if you're losing weight on the "dirty" version of the keto diet.

"The biggest foundation of weight loss is health," says Perez. "If you have any inflammation, if your gut is imbalanced, if your hormones are off, if your blood sugar is off—all of those things are going to make weight loss a lot more difficult and maintaining that weight loss a lot more difficult."

Do Eat: Clean Keto Foods

Monosaturated fats: Dr. Axe recommends keeping nutrient-rich healthy fats on hand, like monosaturated fats such as avocados, coconut oil, ghee, and nut butter. Shusterman says cooking with olive oil, avocado oil, or walnut oil will provide healthier fats than butter even though all are keto-friendly.

High-fiber veggies: A lot of vegetables are high in fiber, which makes their net carbs very low. "Foods like broccoli, cauliflower, kale, romaine lettuce, and asparagus are almost pure fiber, so you can eat as many of them as you want," advises Dr. Axe. To pair the veggies with fat, bake them in butter, sauté them in coconut oil, or steam and eat with guac or tahini. (Related: This Study On Carbs—and Fiber—Will Make You Rethink Your Keto Diet)

Clean hydration: Drink a lot of water, herbal tea, and green vegetable juice, says Axe. Hydration is important when you start the keto diet because you're cutting a lot of sugar and sodium out of your diet.

Eat the rainbow: Once you find some keto meals that work for you, it might be tempting to repeat them. However, it's important to eat produce that's an array of colors to ensure you're getting a good variety of vitamins and minerals, says Perez. (More on that here: Why You Should Eat Produce of All Colors)

Skip: Dirty Keto Foods

Pre-packaged and processed keto diet foods: Just because packaging on some processed foods and snacks boasts being keto-friendly doesn't mean it's a good idea to eat them. "Artificial foods are filled with chemicals and they can disrupt your gut bacteria and can even affect your brain," says Perez. She especially says to avoid artificially sugar-free foods, like chocolate protein bars (which are often sweetened with sugar alcohols). "You're better off having a piece of high-percentage dark chocolate if you want a treat," she says.

Full-fat dairy: Overuse of high-fat dairy products (ex: full-fat cheese) can lead to a diet that is extremely high in saturated fat, which puts people at risk of cardiovascular disease, says Shusterman. "If most of the foods you're choosing are highly processed or filled with saturated fat, you're probably consuming an overall unhealthy diet," says Shusterman.

Processed and red meats: Shusterman also encourages limiting processed and red meats (such as sausage, bacon, and beef) in favor of less processed, leaner options like fish and poultry. "Fish, like salmon, provides omega-3 fatty acids, an essential fat in our diet, and a great source of protein," says Shusterman. If you are going to eat red meat, Axe recommends buying only grass-fed and organic meats. "When cows are grain-fed they are full of omega-6 fats, which is inflammatory," he says. (Here's more about omega-3 and omega-6 fatty acids.)

What to Know Before You Try Keto

Even though the keto diet is getting as much praise as it is criticism, you may want to think twice before giving it a try. First, Shusterman says active women may find that their performance and energy levels suffer on a low-carb diet.

"It's a well-known fact that the brain's first preference for energy is carbohydrates, which are extremely limited on a keto diet, so some people may feel foggy or not quite themselves," warns Shusterman. (That's just one of the downsides of the keto diet.)

You also need to be careful when incorporating carbs back into your diet after being on keto. Shusterman says some of her patients find it challenging to return to a balanced diet after being on keto. She points out that working with a registered dietitian can help make the transition successful. (See: How to Safely and Effectively Come Off the Keto Diet)

Perez says that "experimentation is important," but stresses the importance of doing your research—not just trying the diet because it's trendy. "If it doesn't work for you, it doesn't work for you. And if it does? Great," she says. "Everyone is so different, so sometimes it takes playing around."

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