Does the South Beach diet actually work?

Written by: Kelley R. Hill, MSN, RN-BC

In a Nutshell

• The South Beach Diet was developed by a cardiologist
• Founded on eating “good” carbs and avoiding “bad” carbs
• Primarily a weight loss plan

The South Beach Diet was a best-selling book published by a cardiologist about 20 years ago. It is primarily a weight loss plan, though claims that it is a healthy way to eat regardless of weight loss goals.

PHASE 1:

1. Eliminate most carbohydrate dense foods for 2 weeks, including fruit.
2. Eat lean proteins, non-starchy vegetables, low-fat dairy, healthy fat foods (nuts and seed, avocado), and pulses in limited quantity.
3. Weight loss is estimated at 8-13 pounds, mostly from your midsection.

PHASE 2:

1. Gradually add in limited amounts of whole grains, some fruit, and more vegetables.
2. Remain in this phase until you reach your goal weight.
3. Weight loss is estimated at 1-2 pounds per week.

PHASE 3:

1. Considered the maintenance phase.
2. All foods are allowed in moderation.
3. Carb intake is capped at 28% of daily calories (140 grams).

AVOID:

• Added sugar
• Refined flour
• Dried fruit and fruit juices
• Pineapple
• Watermelon
• Beets
• Corn
• White potatoes
• Whole milk
• Butter
• Coconut oil
• Alcohol
• Red meat that is not lean cut, dark poultry meat

The South Beach diet has evolved over the years and now recommends exercise as an important part of a healthy lifestyle and to help prevent stalls in weight loss.

Although not required, meal plans that include products from the South Beach line, as well as prepared breakfasts, lunches, dinners, and snacks for all phases are available for purchase. The plans are paid one month in advance.

• One-week reboot for $100
• Silver plan for $9.56/day
• Gold plan for $10.88/day
• Platinum plan for $11.87/day
• There is also a diabetes-specific plan.

Lifestyle Impacts

There is no shortage of South Beach Diet recipes available online and in print for all phases, even without purchasing a plan. Purchased plans can be expensive for some at a cost of roughly $300-400 per month.

Cutting out all carbohydrates in Phase 1 could cause fatigue and intestinal upset.

Phase restrictions and heavy reliance on artificial sweeteners may make this diet difficult for some to follow.

Scientific & Expert Support

The South Beach Diet, despite being developed by a physician, is not based on any scientific research. The list of foods to avoid includes some foods that are known to be nutritious.

Experts are concerned about some of the diet’s claims and comparisons, such as a banana and a brownie being essentially the same because they are both high in carbs and can cause blood sugar spikes. It is well known, however, that bananas are a nutrient-rich food containing essential vitamins and minerals whereas brownies have little to no nutritional value whatsoever.

Following an eating plan rich in healthy, whole foods carbohydrates and dietary fats may contribute to weight loss as well as lower cholesterol levels.

Safety

While this diet is relatively balanced and generally safe if followed as outlined in the official books and websites, consulting your physician, and ideally a registered dietician (RD) or nutritionist, before changing your diet or eating habits is recommended. Especially if you are pregnant, breastfeeding, are taking prescription medications, or have existing health conditions.

Severe carbohydrate restrictions may cause brief side effects brought on by ketosis, which can include nausea, headache, difficulty concentrating, dehydration, dizziness, intestinal issues, and bad breath.

STRENGTH OF EVIDENCE: C

There is plenty of quality research supporting the benefit of low-carb diets for rapid weight loss, at least in the short-term, but there is no evidence directly supporting the health effects of the South Beach diet.

OUR RULING:

Like most low-carb diets, chances are you will see rapid weight loss on any low-carb diet. The South Beach diet is now different. The initial weight loss is mostly water weight. However, low-carb does not necessarily mean healthy. If you do choose South Beach diet opt for eating whole foods while avoiding low car processed junk food.

OUR SOURCES:

• Agatston, A. (2003). The South Beach diet. Emmaus, PA: Rodale Books.
• Grayson, C.E. (2004, February). The South Beach diet. MedicineNet. Retrieved from: https://www.medicinenet.com/script/main/art.asp?articlekey=47147
• Mayo Clinic Staff. (2020, April 25). South Beach diet. Mayo Clinic – Healthy Lifestyle: Weight Loss. Retrieved from: https://www.mayoclinic.org/healthy-lifestyle/weight-loss/in-depth/south-beach-diet/art-20048491
• South Beach Diet. (2020). How the South Beach diet works. Retrieved from: https://www.southbeachdiet.com/how-it-works/index.jsp
• National Center for Biotechnology Information.
• Tweed, V. (2020, July 01). The keto-friendly South Beach diet. Better Nutrition, 82(7), 32-36.