A Dietitian’s Review: Atkins and South Beach

By Melinda Maryniuk, MEd, RD, CDCES

We review several different eating approaches in our “Dietitian’s Review” series with the goal of helping people who are looking to evolve their eating style towards better health. It’s important to emphasize that “going on a diet” is very rarely associated with long-term success with weight. We provide these reviews for anyone who wants to improve their health and is looking for an eating approach that will best fit their lifestyle and preferences.


There are several popular low-carb weight loss diets. Both the Atkins Diet and the South Beach Diet were developed by cardiologists.  The focus of both approaches is on eating meals that center on meat, poultry and fish. They both include the option to purchase a wide variety of shakes, bars and even packaged meals.

What foods does this diet focus on?

While there are some differences between the two approaches, they both begin with a very restricted phase for 2 weeks.  During that time, carbohydrates (from whole grains, starches, fruit dairy and most veggies) are strictly limited.  After this intro phase, both diets move the individual through a structured sequence of gradually adding some foods back into the diet based on the progression of weight loss.  While originally the Atkins diet avoided most veggies, it has evolved to allowing more high-fiber veggies.  The South Beach diet has always emphasized protein choices that are lower in saturated fat (such as avoiding dark meat poultry), while Atkins does not limit saturated fat (and butter is considered fine to eat). South Beach puts no limit on non-starchy vegetables.

Is it effective?

There is no question that some people find a very strict approach that limits foods that are high in carbs (which are the foods commonly overeaten) results in weight loss for the short term.  However, data for longer term (over 3 months) weight loss is weak.  Generally people find these approaches difficult to stick with for the long term and they end up reverting to old habits.

What are some pros and cons?

Pros:  Weight loss can be dramatic in the first few weeks if the diet is followed carefully.

Cons:   Very restrictive.  The long term effect of omitting or limiting key food groups (whole grains, fruits, dairy) over time is not known.  Difficult to stick to over time and weight re-gain is common.

How do I learn more?

  • Atkins Diet: atkins.com (or any one of the books by Dr. Atkins or his colleagues)
  • South Beach Diet: southbeachdiet.com (or any one of the books by Dr. Agatston)

It is strongly recommend if you choose to try one of these options, you let your doctor know.

What do I buy at the grocery store?

Note: There are many approaches to weight loss that can be successful for people.  My Weight– What to Know does not recommend a particular diet, but is happy to share facts about a variety of approaches. As with all meal planning approaches, regular exercise is recommended.  

Eating a healthy diet and being active are both really important for being healthy, but for many people diet and exercise alone aren’t enough to help them reach their weight-loss goals. If this sounds familiar, read this fascinating article about what to do when diet and exercise aren’t getting you to where you want to be.

UPDATE: A recent study from the NIH suggests that a diet high in ultra-processed foods led to overeating and weight gain. Watch our Facebook Live episode that covers what to know about ultra-processed foods here.

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This article was sponsored by Novo Nordisk Canada. All content is created independently by My Weight – What To Know with no influence from Novo Nordisk.

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