Keto Versus Atkins: How Do the Two Low-Carb Diets Compare?

There is certainly no shortage of diet types to choose from these days. From Whole30 and gluten-free to plant-based living, it can be hard to find one that works for you and your real life.

While dieting trends are constantly changing today, the most popular diets promote real whole foods for lasting results that go beyond weight loss.

The ketogenic diet and the Atkins diet are two of the most followed nutritional plans because of their low-carb approaches.

With thousands of fat loss success stories from plans like the 28-Day Keto Challenge, it’s no wonder low carb diets are all the rage.

If you’re looking to lower your intake of carbohydrates in a healthy way, keto or Atkins may be good options for you. But, even though they have a low-carb approach in common, there are a few key differences between the diets.

Here, experts share how these diets compare and what to know before starting them.

What is the ketogenic diet?

Also known as the keto diet, it’s a super high-fat diet that also includes an adequate amount of protein and a very low carbohydrates intake.

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“The keto diet is 70 percent fat, 25 percent protein, and 5 percent carbohydrates,” says Samantha Lynch, registered dietitian nutritionist.

Due to the low amount of carbs in this diet, the liver converts fat into fatty acids and ketone bodies. This forces the body to burn fats rather than carbohydrates. These replace what would normally be converted into glucose (from carbohydrates) as the source of energy.

“It typically takes three to six weeks for the body to make the transition to running on fat,” adds Paul Salter, R.D., M.S., and founder of Fit in Your Dress.

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What is the Atkins diet?

Dr. Robert Atkins founded this diet, also known as the Atkins nutritional approach, in 1972. Marketed as a low-carbohydrate diet, it’s often regarded as the diet that started the low-carb craze.

“The diet began as a simple low-carbohydrate approach. [It] emphasized more protein and fats (including saturated fats) and a reduction in carbohydrates.

Therefore carbohydrates consumed [should] come from high-fiber, satiating options,” Salter says. Over the years the diet has evolved to include four distinct phases.

  1. Induction: You are restricted to no more than 20 grams of carbohydrates per day. Emphasis is placed on high-fat and high-protein foods, with the source of carbohydrates coming from dark, leafy greens.
  2. Balancing: You begin to incorporate more nuts, low-carbohydrate vegetables, and small amounts of fruit.
  3. Fine-tuning: Once you’re close to your goal weight, you will begin to add more carbohydrates until the weight loss slows down.
  4. Maintenance: You may eat as many high-fiber carbohydrates as you can tolerate without regaining weight.

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Keto Versus Atkins: The Pros and Cons

Before you settle on which diet that you want to move forward with it’s important to be aware of the pros and cons for each.

Atkins Diet: Pros

The Atkins diet offers quick weight loss results and reduces appetite and cravings, especially for sweets.

According to Lynch, there is less insulin produced in the body. This is because the diet is low on carbs and doesn’t include any sugar.

Insulin in the pancreas often lowers blood sugar levels, she adds, leading to fluctuating blood sugar (glucose) levels. These fluctuating levels are responsible for cravings. So when there is less insulin produced, there are less fluctuating sugar levels, and, therefore, fewer cravings.

Due to the dip in insulin production and blood sugar levels, the Atkins Diet can be a great resource for reversing diabetes or pre-diabetes and help people manage PCOS, says Lynch.

“If you have quick weight loss, even if you have like a 10 percent weight loss of your body weight, your blood sugar levels are more likely to be within normal ranges. We always shoot for a 10 percent drop,” she says.

Lynch adds that in order to stabilize blood sugars, you should eat a high-protein, high-fiber diet.

Atkins Diet: Cons

The Atkins diet can also cause electrolyte imbalances. Additionally, according to Lynch, the Atkins diet can lead to reduced muscle mass and weakened bones.

“If you lose weight quickly, your body is obviously going to use ketones. But it will also use your muscle mass for energy,” explains Lynch.

“If you use your muscle mass for energy, you’re lowering your muscle mass. Because so many people gain back the weight, what happens is they actually have a higher percent body fat and less muscle mass.”

Additionally, Lynch says that many people who gain back the weight find that they have a lower metabolic rate than they did before they initially lost the weight. Though studies have been conducted to try to prove this, further research is required.

The diet may also lead to osteoporosis, says Lynch. Salter adds that “with a very high fat intake, if somebody is not restricting their fat appropriately between saturated and unsaturated and relying too heavily on saturated fat, that could pose a risk for osteoporosis.”

Again, there have been various studies done that both prove and dispute this. To make sure that you’re consuming all the vitamins and minerals you need, it’s best to consult a registered dietician.

Keto Diet: Pros

Historically, the keto diet was invented to help people with epilepsy. According to Salter, the keto diet was hypothesized to help people with epileptic seizures.

It “robbed the brain of sugar,” including sugar that came from broken down carbohydrates. He explains that sugar was believed to fuel the nerve impulses that caused the epileptic seizures.

Similarly to the Atkins diet, the keto diet can also help with the maintenance of blood sugar levels and reduce the risk or severity of type 2 diabetes.

Additionally, studies have shown that people in ketosis have decreased levels of triglycerides and increased levels of HDL cholesterol (good cholesterol).

“By reducing blood sugar levels, you’re going to reduce triglycerides. Triglycerides are basically excess carbohydrates or they’re fat in the liver. Triglyceride levels are affected by the incline of blood sugar levels and weight loss,” Lynch explains.

She adds that high consumption of soluble fiber may also help lower cholesterol.

The lower blood sugar levels also play a role in the decreased risk of heart disease.

“Again you’re removing tons of high sugar food. And you’re eating a large number of leafy greens which are healthy, good-for-you fats. That is going to have a positive effect on your heart health as a whole as well,” Salter says.

Keto Diet: Cons

Arguably the biggest con for the keto diet is that many people never truly achieve ketosis.

“The main difference is the Atkins diet includes a gradual increase in carbohydrate intake. [This is] far more sustainable, after completing a period of time following a very-low-carbohydrate (ketogenic) approach. The ketogenic diet is a very-low-carbohydrate diet at all times,” Salter says.

“[With] the ketogenic diet, you have to meet these precise eating guidelines. If you do not eat to the guidelines, you actually don’t induce the state of ketosis necessary to experience those benefits.”

Lynch echoes the sentiment. “Unfortunately, most Americans want results and they want them quick. I always remind people: You didn’t gain the weight overnight, so be realistic with your expectations,” she says.

Additionally, the keto diet, when followed incorrectly, may lead to an electrolyte imbalance.

“A lot of people will experience an electrolyte imbalance, especially when transitioning from a traditional western diet to a keto diet. When you stop eating carbs you do lose a lot of sodium and potassium that are common in those foods,” says Salter.

He adds that it’s important that people be aware of the risk and take electrolyte supplements to replenish their stores. This is especially true for people who work out regularly and lose electrolytes through sweat.

There are four types of electrolytes to be cognizant of: potassium, sodium, magnesium, and calcium. According to Lynch, many of the foods not allowed on these low-carb diets provide the highest sources of electrolytes for most people.

“A lot of the grains have magnesium, potassium comes in a lot of fruits and vegetables,” she says. In order to ensure you get the nutrients you need, she adds that you should consult a dietician before starting the diet.

Which diet is better for me?

An important thing to keep in mind is that if you have a fit lifestyle, both diets probably won’t work well for you. “For a fit and active lifestyle, it’s going to be hard to maintain either of these diets,” Lynch says.

“However, if you do lower-intensity exercises like yoga, pilates, barre, and walking, it will be easier to maintain. Remaining in ketosis is not advised and can be dangerous.”

It’s also important to keep in mind that, when it comes to keto versus Atkins, the keto diet lays out specific guidelines. However, the Atkins diet does not.

“The main difference is the ketogenic diet is much more precise. You have to be precise in order to achieve those benefits,” says Salter.

“I think the Atkins diet is more flexible and might be less intimidating, which is something some people gravitate towards. However, on the other end of the spectrum, some people need that rule-based approach. [They] need all of these specific diet guidelines in place because otherwise, they’re going try to break the rules or bend them. So it depends on the individual.”

Regardless of which diet you choose, there are two major things to keep in mind before starting any new diet. The first is to always check with a physician or registered dietician.

You want to ensure that the changes you plan to make to your diet are right and safe for you. The second is to make sure that you pick a diet that can become a lifestyle.

“My biggest piece of feedback to people is to make sure it’s an approach you can foresee yourself doing for the long term. Not a quick-fix rash diet approach,” says Salter.

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