Keto vs. Atkins: What's the Difference?

Bread is off limits in both, obviously—but there's more to it.

Photo: Getty Images/photka

If you been reading all about the ketogenic diet and feeling a little déjà vu, you're not alone. The high-fat, low-carbohydrate diet sounds a lot like the Atkins Diet, which was developed by the late cardiologist Robert Atkins in the '70s and took off again in the early 2000s. There are some fundamental differences between the two, however. Let the keto vs Atkins diet showdown begin.

The Similarities Between Keto Vs. Atkins

"The most obvious similarity is they're both about carb restriction," says Kelly McGrane, M.S., R.D., founder of The Healthy Toast in Denver. Another similarity is that you're not counting calories on either one; it's more about macronutrient distribution. And for most people, consuming very little carbs is drastically different than their typical diet, so both can lead to weight loss. (

"Both diets advocate for impressive weight loss quickly," says McGrane, "but there are really no good studies showing that long-term weight loss sticks with either one of them."

When you're just starting out, there's a good chance either diet will make you feel less than stellar at first (ever heard of the keto flu?). "If you've been eating a lot of carbs, you're likely to feel sluggish and even shaky when you dramatically lower them," says McGrane.

Keto and Atkins each recommend eating as many whole foods as possible (i.e., not falling into the trap of "dirty keto,"), yet technically, they can both be followed by eating indulgent foods like bacon, full-fat cheese, and processed low-carb packaged snacks, so "it really depends on how the individual is doing it," says McGrane. There are ways to make eating on either diet healthier, such as swapping in salmon for ribeye, which will give you more vitamins. "Anything—even if it's healthy—in excess, can be too much for the body," she says.

The Differences Between Keto Vs. Atkins

While you're not sticking to a specific caloric intake on either program, following keto does require precisely calculating where your calories are coming from, which is 70-80 percent from fat, followed by 15-20 percent protein and just 5 percent from carbohydrates, says McGrane. A key difference between keto vs. Atkins here is that on keto, you can't eat too much protein because it can be broken down into glucose, which is typically the body's source of fuel, "and the whole point is you have to be breaking down fat to get energy" to be in ketosis, she notes.

Atkins doesn't restrict protein. The classic Atkins 20 Diet is broken into four stages. The initial phase—which is basically a ketogenic diet—includes meat, fish, chicken and shellfish; eggs; fats like butter and olive oil; cheese; and low-carb vegetables. As you progress through the diet and reach stage four, however, you're able to introduce more foods back in, such as fruit, starchy vegetables (sweet potatoes, corn, beets) and whole grains (quinoa, whole-wheat bread, oatmeal), gradually increasing your daily carb intake.

Keto, on the other hand, eliminates any fruits, and you don't get to add complex carbs (like sweet potatoes) back in—ever—like you can on Atkins, says McGrane. Overall, keto ends up feeling a lot more restrictive as your food choices remain limited as long as you're on the diet. (FYI, that's just one of the reasons why this dietitian is completely against keto.)

Keto Vs. Atkins: Beyond Weight Loss

While keto and Atkins are touted as weight-loss diets, both have been advertised as treatments for a wide range of diseases, including type 2 diabetes. (

A claim of the Atkins diet is that low-carb diets can dramatically improve blood glucose control and insulin resistance, which makes it a good choice for patients who need this; yet a study published in Nutrition & Metabolism found that a ketogenic diet actually led to greater improvements in glycemic control than a low-glycemic diet (like Atkins). Another published review found that very low-carb diets, such as keto, resulted in better improvements in blood sugar control, weight loss, and medication reliance compared with other diets.

The Bottom Line On Keto Vs. Atkins

McGrane doesn't recommend either diet in the long term, because they require cutting out major food groups. She says women following keto or Atkins can face "very real nutrient deficiencies," and that keto isn't the best diet for building muscle "because if you're truly following it, you're likely to have lower energy levels," at least in the beginning. (FYI, here are some other side effects to keep in mind before trying keto.)

However, if you're someone who tends to reach for a lot of sugary, processed snacks, following one of these can be a good *short-term* solution to clean up your diet, says McGrane. In the long term, it comes down to choosing a diet that can become a lifestyle for you, rather than looking for a quick fix.

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