What’s the difference between keto and Atkins, anyways?

It’s safe to say that when it comes to low-carb eating plans, the ketogenic diet is king. It was one of the most popular eating plans of 2018, it’s spurred the popularity of MCT oil and other fat-friendly foods, and inspires loyalty (and backlash) so intense that it’s sparked intense public celebrity feuds.

But for those of us old enough to remember the early 2000s with any clarity (sorry, Gen Z!) the keto diet is reminiscent of another low-carb eating plan: the Atkins diet. Once wildly popular, the diet somewhat faded in the background in favor of other eating plans like Paleo and Whole30.

But now that low-carb eating is back in the zeitgeist, it’s worth giving both keto and Atkins a look. Given that they’re both low-carb, high-fat diets, they can’t be that different, right? Not quite, say experts.

Remind me, what is keto again?

In case you’ve been living under a rock for the past two years: “The ketogenic diet is a very low-carb, high-fat, moderate-protein way of eating,” says Sam Presicci, RD, CPT, lead registered dietitian at Snap Kitchen. The keto macros are very strict, she says, with adherents typically getting only 5 to 10 percent of their daily calories from carbohydrates, 15 to 20 percent from protein, and a whopping 75 to 80 percent from fat.

The diet was originally created in the ’20s to help children with drug-resistant epilepsy control their symptoms; it has recently become way more popular among adults due to its ability to burn fat (and thus promote weight management), Presicci says.

“When glucose is depleted, ketone bodies are created and can cross the blood-brain barrier as energy for the brain and central nervous system. This is a different state of metabolism for the body,” explains Ginger Hultin, RDN, a spokesperson for the Academy of Nutrition and Dietetics. This metabolic state is known as ketosis, and it’s attributed to other potential health benefits (besides weight management) such as increased energy, reduced inflammation, and balanced hormones and blood sugar levels.

For more intel on the keto diet, check out this video: 

A healthy keto diet will consist of well-raised animal proteins (like grass-fed beef, pastured chicken, and wild-caught seafood), healthy fats (including avocados, extra virgin olive oil, nuts and seeds, olives, and coconuts), and non-starchy vegetables, like leafy greens and cruciferous veggies, for fiber and micronutrients.

Cool, so what is the Atkins diet?

The Atkins diet has been around since the 1970’s; it was created by cardiologist Dr. Robert Atkins after researching ways people could safely lose excess weight without restricting calories, according to the Atkins website. The eating plan became super popular in the early 2000s (anyone remember that Arrested Development episode when the Bluths collectively tried to go low-carb?).

Like keto, Atkins is a low-carb, high-fat diet. It functions in three to four phases, where a person’s macronutrient intake changes throughout. “In the first two weeks, you eat less than 20 grams of carbs per day,” says Presicci. “Then you slowly add in more carbs from vegetables, nuts, and small amounts of fruit.” This means that the macros shift on the diet—per US News and World Report, phase one of the classic Atkins diet (also called Atkins 20) calls for around 10 percent of a person’s daily calories coming from carbohydrates, 30 percent from protein, and 60 percent from fat. (This first phase technically puts you ketosis, according to the Atkins site.) Those ratios shift by the end of the program to allow for more carbs and less fat.

There are other versions of Atkins, like the Atkins 40, which is just a low-carb eating plan that doesn’t have phases in the same way as Atkins 20. It allows for 40 grams of carbs per day (hence the name) and flexible servings of fat and protein.

So keto diet vs Atkins: What’s the difference?

While both plans are low-carb and high in fat, the macros are a bit different. Keto allows for less protein and more fat than in the strictest phase of Atkins.

Another big difference: Keto restricts carbs indefinitely in order to sustain ketosis, says Presicci. Meanwhile, Atkins increases a person’s carb intake during its later phases, thereby taking a person out of ketosis. The main focus of Atkins isn’t necessarily to be in ketosis, of course, while that is the main purpose of the ketogenic diet, adds Hultin.

It’s important to note that the long-term benefits of a low-carb plan, whether it’s Atkins or keto, are up for debate in the health community. Some health experts warn that restricting carbohydrates for extended periods of time could cause pretty negative health effects, from constipation due to lack of fiber to potentially skewing delicate hormone balances in women. Research is also mixed: One 2018 study found that people who cut carbs increased their metabolism and burned more calories compared to people who cut fat, while another one published earlier in the year found no significant difference between low-carb and low-fat plans for weight management. Yet other research has found that low-carb, high-fat diets have the potential to treat diabetes and potentially even schizophrenia. More robust human clinical trials are needed before one can make definitive conclusions either way about the health merits of this style of eating.

However, because Atkins ultimately allows for more carbs than keto, it could come with some health perks harder to get on keto. “Most people will be able to eat more fruits and veggies [during the maintenance phase of Atkins] therefore getting more fiber, vitamins, minerals, and antioxidants so that could be seen as ‘healthier,’” says Hultin. “It depends on the individual, their needs, their preferences, and their health history, though.” It also depends on one’s interpretation of keto; certain iterations like Ketotarian advocate for slightly more carbs, no meat, and lots more vegetables.

“I wouldn’t necessarily say one is healthier than the other. Instead, they both depend on the types and quality of the foods you’re eating,” says Presicci. But she thinks keto may have some extra points in its favor, depending on an individual’s health needs and priorities. “Since the ketogenic diet has more guidelines around it, I think there’s more potential for benefit. Atkins is a little more ambiguous once you get out of the first two phases,” she says. (To be fair, it could also be argued that the rules and restrictions make both plans potentially tough for people to maintain.) She adds that one might eat more whole foods on keto than on Atkins. “The Atkins-branded snacks and drinks are not based in real food and have less than stellar ingredients,” Presicci says.

“Having said that, if done properly with limited processed foods, ample vegetables, and well-raised proteins, they can both be healthy options that lead to benefits,” Presicci says. A good rule of thumb to follow no matter what eating plan you choose.

Want to learn about more healthy eating plans? Here’s everything you need to know about the Mediterranean diet’s benefits. And here’s what a healthy plate on the Paleo diet looks like.