Atkins Vs. Keto: What is the Difference?

Atkins and Keto are the two biggest names in low-carb dieting. If there were a dieting awards show, they’d be competing for camera time. 

Although most people have heard of Atkins and Keto, fewer people can differentiate between the two. They’re both low-carb diets—what more is there to know?

A lot, as it turns out. Atkins and Keto may overlap on macros, but only one of them is explicitly a weight loss diet. The other focuses on promoting a unique metabolic state (ketosis) that has many potential benefits, including weight loss. 

You can probably guess which is which. Let’s compare Atkins vs. Keto—including their benefits—so you can make more informed decisions about your food choices. 

What Is The Atkins Diet?

The Atkins diet is a low-carb diet developed by Dr. Robert Atkins in the 1970s. His book The New Diet Revolution was wildly popular in the early 21st century, selling millions of copies to become an overnight success. 

At the time of publishing, there wasn’t much evidence to support the claims behind the Atkins diet. But since then, a handful of studies suggest that Atkins is effective for its advertised purpose: weight loss.[*]  

In terms of macros, the Atkins diet is low in carbs, high in fat, and high in protein. Most people know Atkins as a diet that promotes unlimited consumption of meat, cheese, eggs, butter, and other high-fat foods while forbidding carbohydrate-containing foods. 

The Atkins diet features four phases. Each phase is based on the grams of net carbs (total carbs - fiber - sugar alcohols) you can consume at each weight loss milestone. 

1. Induction Phase. Rules: Consume under 20 grams net carbs per day until within 15 pounds of your weight loss goal. 
2. Phase 2. Rules: Consume 25-50 grams net carbs per day until within 10 pounds of your weight loss goal. 
3. Phase 3. Rules: Consume 50-80 grams net carbs per day until you hit your weight loss goal. Maintain for one month. 
4. Phase 4. Rules: Eat up to 100 grams net carbs per day for long-term maintenance. 

What Is The Keto Diet?

The Keto diet (short for the Ketogenic diet) is a very low-carb diet designed to promote a fat-burning state called ketosis. 

When you eat Keto, you consume 55-75% of your calories from fat, 15-35% from protein, and less than 10% from carbohydrates. Keeping your macros in these ratios keeps the hormone insulin low, promoting the breakdown and oxidation (burning) of body fat.[*]

By burning fat on Keto, you produce molecules called ketones that fuel the brain and body with clean, efficient energy. Making ketones (i.e., being in ketosis) can also help with weight management by reducing hunger and increasing energy expenditure.[*][*] More on that later. 

Atkins vs. Keto: Similarities

There’s plenty of overlap between Atkins and Keto. For starters, both are low-carb diets geared towards weight loss. 

The induction phase of Atkins is more or less a Ketogenic diet. Limiting net carbs to under 20 grams per day is highly likely to promote ketosis, even if protein intake is fairly high. 

Speaking of protein, there’s a type of Keto diet called the modified Atkins diet. This high-protein version of Keto entails eating around 30-35% of your calories from protein, 50-60% from fat, and under 10% from carbohydrates.

Let’s take a look at some of the common foods allowed on both Keto and the Atkins diet:

• Meat and poultry
• Fish and seafood
• Eggs
• Butter, cheese and cream
• Nuts and seeds
• Healthy fats, such as olive oil and coconut oil
• Herbs and spices
• Low carb sweeteners

With so many similarities, it is easy to see why these dietary terms are sometimes used interchangeably.

Keto vs. Atkins: Differences

In terms of what you eat, the main differences between Atkins and Keto are that: 

1. Atkins allows more carbs (in phases 2-4). 
2. Atkins is generally higher in protein.
3. Atkins does not require as high a fat intake as Keto.

The carb rules are the key difference. The higher carb phases of Atkins are unlikely to promote ketosis.

The Keto diet is all about keeping you in ketosis. The early stages of the Atkins diet may promote ketosis too, but as carb intake increases with each phase, you’ll rely more on sugar and less on fat for energy. 

To be clear, some people (like athletes) do better on higher carb intakes. Cycling in and out of ketosis is a strategy worth experimenting with.   

Low-Carb Diet Benefits

Most of the benefits of low-carb diets like Atkins and Keto are likely attributable to ketosis. Let’s look at the main ones. 

#1: Weight loss

Both Atkins and Keto have been shown to help with weight loss in a variety of populations.[*] Of the two diets, there’s more evidence for Keto, especially for obese people and those with diabetes.[*][*][*][*] 

Why do low-carb diets help people lose weight? A couple of reasons. 

First, being in ketosis reduces hunger, which in turn curbs snacking. When you eat less, you’re more likely to lose weight. 

Very low-carb diets have also been shown to increase metabolic rate (the rate at which you burn calories) compared to low-fat or low-glycemic diets.[*] 

So less energy in, more energy out. It’s a good formula for weight loss. 

 #2: Blood sugar regulation

Reducing blood sugar levels is the primary therapeutic goal for type 2 diabetes. Low-carb diets have helped many people with diabetes achieve this goal. 

Case in point: a recent consensus report published in the journal Diabetes Care reported that reducing overall carbohydrate intake demonstrates “the most evidence for reducing glycemia” in people with type 2 diabetes.[*] 

The mechanism makes sense. By keeping carbs low, you keep your blood sugar low. Carbs digest to blood sugar, after all. 

The Keto diet has even been shown to help people with diabetes reduce or eliminate their blood sugar medications.[*] Be sure, however, to consult your medical professional before using low-carb diets therapeutically. 

#3: Brain health

Being in ketosis may improve cognition. In one study published in Psychopharmacology, older people performed better on a series of tests with elevated blood ketones.[*] 

Scientists are also studying the Keto diet as a potential Alzheimer’s therapy. The aging brain, it’s believed, runs better on ketones than glucose—and this may help stave off dementia.[*] 

#4: Other ketosis benefits

Other potential benefits of a low-carb diet include:

• Inflammation reduction[*]
• Potential cancer therapy[*]
• Improved gut health
• More stable energy
• Enhanced endurance capacity[*]

Check out our article on Keto Beyond Weight Loss for a deeper dive on this topic. 

Atkins or Keto?

In many ways, early phases of Atkins and Keto are the same. They’re both low-carb weight-loss diets that can promote ketosis. Both diets have the potential to lower blood sugar, and may be beneficial for people with type 2 diabetes.

Later phases of Atkins, however, are probably too high-carb to promote ketosis. This may negate some of the desired benefits. 

One approach is to start with a modified Atkins diet, see how you feel and perform, then add carbs back in if desired. Maybe you stick with high-protein Keto, maybe you cycle in some carbs, or maybe you move to a whole foods Paleo diet. 

Let your body be your guide.