ThitareeSarmkasat/Getty Images

They’re two of the most popular low-carb eating plans out there, but how do they stack up against each other?

Carolyn Williams, PhD, RD
August 14, 2018

Low-carb eating plans are rising in popularity, thanks to research suggesting they’re as effective for weight loss as low-fat diets. You’re probably familiar with two of the most popular low-carb diets, the ketogenic diet and the Atkins Diet. While keto is currently making the most waves right now, Atkins certainly deserves credit for starting the low-carb diet trend in the first place.

But what is the difference between these two diets? And is one better than the other? Let’s take a closer look at how keto is different from Atkins in terms of carbohydrate, protein, and fat intake, as well as potential health benefits and concerns.

Low Carb or Very Low Carb?

While keto and Atkins are both low-carb diets, carb intakes can vary greatly between the two. But what does a low-carb diet actually mean? There is no exact definition for a “low-carb diet” or LCD, but generally it means consuming less than 30% of your daily calories from carbohydrates (about <150g of carbohydrates per day). On the other hand, a “very low-carb diet” or VLCD usually refers to eating only 5-10% of calories from carbs (approximately 20-50g of carbs per day).

Keto and Atkins are both below the USDA’s current health recommendations for carbohydrates (45-65% of your daily calories from carbs), but is one more restrictive than the other?

Keto Diet: Very-Low Carb  

The goal of ketogenic diets is to put the body into a state of ketosis. For most individuals ketosis can be induced by consuming <50g of carbs, but some keto diet followers try to keep total carbs to 20g or less.

Atkins Diet: Low Carb and Very-Low Carb

The Atkins diet ranges from being a VLCD and a LDC depending on Phase and weight loss goal. During Induction or Phase 1, the plan advises a very low-carb intake of 20-40g of net carbs. This amount slowly increases and once weight goal is met individuals often eat 80-150g net carbs per day making it still “low-carb” but significantly higher than keto.

Higher Protein or Higher Fat?

Even if weight loss is the goal, energy needs have to be met with adequate calories—most of which must come from protein and fat. However, keto and Atkins differ in the percentage of those calories from protein and fat. See the chart below for a breakdown of where calories come from among the diets, as well as the national health guidelines (Acceptable Macronutrient Distribution Range or AMDR values).

 

Breakdown of Where Daily Calories Come From

 

Carb

Protein

Fat

Keto

5-10%

15-25%

70-80%

Atkins (Induction)

5-10%

25-35%

55-70%

Atkins (Maintenance)

15-30%

25-35%

45-60%

AMDR Comparison

45 to 65%

10 to 35%

20 to 35%

On the keto diet, the majority of your calories come from fat. For the Atkins Diet, fat intake is slightly less, but protein intake is slightly higher. So, how do these percentages translate to a day of eating on both plans? See the chart below, which compares daily intakes of carbs, protein, and fat on keto and Atkins to AMDR values.

 

1500-Calorie Day

2000-Calorie Day

 

Carb (g)

Protein (g)

Fat (g)

Carb (g)

Protein (g)

Fat (g)

Keto

19-38

56-94

117-133

25-50

75-125

155-178

Atkins (Induction)

19-38

94-131

92-117

25-50

125-175

122-155

Atkins (Maintenance)

56-113

94-131

75-100

75-150

125-175

100-133

AMDR Comparison

169-244

38-131

33-58

169-244

38-131

33-58

Health Benefits of Keto and Atkins

While the Atkins Diet was created specifically for weight loss, the ketogenic diet was developed in the 1920’s as a treatment for epilepsy by inducing ketosis to reduce seizure episodes. But recent research suggests that both the ketogenic and Atkins diets may provide health benefits such as weight loss, improved blood sugar, better heart health, and even reduced risk of cancer and neurodegenerative diseases.

Challenges of Keto and Atkins

Although research suggests many positive outcomes, there are still a lot of unknowns when it comes to low-carb diets, particularly in regards to long-term health and if certain individuals could benefit more than others. Research also hasn’t come to a conclusive answer as to how high levels of fat intake, and the makeup of that fat, impacts overall health when following a low-carb diet long-term.

Keto Challenges: The VLCD nature of keto makes it particularly difficult to reach nutrition recommendations for certain nutrients like fiber, calcium, Vitamin C, folate, and beta-carotene. Eating such a high level of fat while meeting energy needs is challenging too, in part because fat provides greater satiety and ketosis can reduce appetite. Also, it requires planning to ensure adequate low-carb, high-fat food options are readily available.

Atkins Challenges: Reaching for protein foods like chicken, fish, or beef is often easier than filling up on fat—but this actually causes many Atkins diet followers protein to exceed the recommendations. Excessive protein intake requires additional work by the kidneys. Because water intake should increase proportionately, the Atkins diet is not recommended for those with certain health conditions like kidney disease. Depending on the level of carbohydrates consumed, meeting recommendations for the same nutrients mentioned in the ketogenic diet can be difficult.

Read these articles before trying a low-carb diet:

The Verdict on Keto and Atkins

Right now, there’s not enough data to suggest that one diet is better than another—or that either are superior to lower-fat eating plans. Research points towards low-carb diets having the biggest health improvements in individuals with insulin resistance and obesity, and both keto and Atkins diets have demonstrated positive effects in most of those individuals when studied. For now, if you are wanting to take a low-carb approach to eating, choose one that meets your lifestyle, health, energy and nutrient needs.