Famous Diet Options: What's the Difference?

Atkins, Weight Watchers, South Beach and Zone diets did not produce very different weight loss results

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Diet options for weight loss and heart health abound. But do some stand out from the rest? Not really, a recent study found.

A new study looked at past research on the famous Atkins, South Beach, Zone and Weight Watchers diets. The researchers measured how well the diets worked by seeing how long their weight loss results lasted.

Mark J. Eisenberg, MD, MPH, of McGill University in Montreal, Canada, led the study. The differences between the diets were small, the researchers concluded.

All four diets had modest short-term results.

  • The Atkins diet focuses on low-carbohydrate, high-protein foods. Eating fiber and good fats is also encouraged. In the current study, patients on the Atkins diet lost between 4 and 10 pounds on average in the span of one year.
  • The South Beach diet focuses on lean proteins and fiber. This diet limits carb and fat intake in the beginning. But good carbs and fats are re-introduced later on. Study participants on the South Beach diet lost between 7 and 13 pounds on average. These were results from only one past study, these researchers noted, so the results may not represent usual South Beach diet results.
  • The Weight Watchers diet has set meal plans. This diet uses a point system based on calories eaten. Eating lean proteins is encouraged. Weight Watchers is also known for its high-accountability weight loss method from support groups. Patients on the Weight Watchers diet lost between 6 and 13 pounds on average in one year.
  • The Zone diet focuses on lean proteins and colorful carbs like dark green, leafy vegetables. This diet limits fats and heavily restricts processed foods. Patients on the Zone diet lost 3 to 7 pounds on average in this study.

The findings suggested that Weight Watchers may have better long-term weight loss success than the other diets. This was because only Weight Watchers dieters showed steady weight loss results.

"The one thing that all of these diets have in common is the elimination of sugar and other easily digestible carbohydrates from the diet," said personal trainer and wellness coach Rusty Gregory.

"One of insulin's primary purposes is to carry blood glucose (sugar) to muscle and fat cells to be used for energy and stored for later use. They don't call insulin the fat storage hormone for nothing," said Gregory, who is also author of "Self-Care Reform: How to Discover Your Own Path to Good Health" and "Living Wheat-Free For Dummies."

Tina Marinaccio, MS, RD, CPT, owner of Health Dynamics LLC in Morristown, NJ, and adjunct professor at Montclair State University, told dailyRx News that many diets can promote weight loss and heart health, but the best ones are personalized.

“Any diet that restricts calories will result in weight loss," she said. "But, can the weight-loss be maintained? That seems to be the real challenge ... For managing weight, and maintaining cardiovascular health, plant-based diets are the way to go. Individualized programs should be developed with a registered dietitian, based on preferences and lifestyle, to promote adherence, and therefore optimal health.”

There was not enough data to see how well the diets decreased heart risk issues, Dr. Eisenberg and team noted. The limited data suggested that heart health outcomes were similar in patients on the Atkins, Weight Watchers, South Beach and Zone diets. Dr. Eisenberg and team called for more research on this topic.

The study authors noted that only focusing on four diets may have limited their study. Other diets could have produced different results, they said.

Dr. Eisenberg and colleagues also noted that the relatively small number of study participants might have limited the study — the findings may not apply to the general population.The authors took an in-depth look at 26 past studies on these diets. They studied a total of 3,575 people.

This study was published Nov. 11 in Circulation: Cardiovascular Quality and Outcomes.

The Canadian Institutes of Health Research funded this study. The authors disclosed no conflicts of interest.

Review Date: 
November 14, 2014
Last Updated:
December 4, 2014