south beach diet

Originally designed in the 1980s by cardiologist Arthur Agatston and dietician Marie Almon to help prevent heart disease, the South Beach Diet gained popularity in the early 2000s as a means to lose weight. But does the research live up to the claims, and how easy is the diet to stick to in the long term? Here we explain the theory of the diet and what it involves, and whether it can help you achieve success on your weight loss journey with Phen Caps.

The History & Theory of the South Beach Diet

Agatston had observed how patients who were advised to stick to low-fat diets in order to reduce cholesterol and prevent heart disease had trouble sticking to the diet and wanted to find a solution for them. Drawing conclusions from work by David J. Jenkins on the Glycemic Index, he proposed that patients on low-fat diets were eating no less food than they had been before, but were hungrier due to consuming additional sugars and simple carbs (foods high on the glycemic index), which are rapidly reduced to sugar by the digestion process.

This excess amount of sugar leads to an over production of insulin and low blood sugar, in turn leading to increased hunger and the consumption of more sugar. Agatston was also aware of the low-carbohydrate diet popularized by Atkins in the 1970s, but feared that this diet would lead to too few carbohydrates, too much saturated fat and too little fiber. So, he developed his own diet plan instead, based around replacing ‘bad’ carbs and ‘bad’ fats with ‘good’ carbs and ‘good’ fats.

How the South Beach Diet Works

According to Agatston, it is not carbohydrates that are to blame for hunger cycles, but rather carbohydrate-rich foods that the body digests quickly, resulting in a spike in blood sugar. These foods include the heavily refined sugars and grains that make up a relatively large part of the typical Western diet, and which are eliminated by the South Beach Diet in favor of relatively unprocessed foods such as vegetables, beans and whole grains. Trans-fats and saturated fats are also discouraged; specifically, the diet replaces the fatty portions of red meat and poultry with foods rich in unsaturated fats and omega-3 fatty acids, such as lean meats, nuts, and oily fish. Like many diets, the South Beach Diet also uses phases to take the dieter from a rigid two-week diet in phase 1 to a more liberal plan of lifetime maintenance in phase 3:

Phase Details Foods You Can Eat Foods You Can't Eat
  • Last for 2 weeks
  • Aims to eliminate cravings
  • Rapid weight loss – only for those with more than 10lbs to lose
  • Low GI vegetables – fresh or frozen
  • Lean meat and fresh fish
  • Eggs
  • Low fat dairy
  • Nuts and seeds
  • Unsaturated fats – e.g. olive oil, avocados
  • Carbs – e.g. bread, rice, pasta, cereal
  • High GI veg – e.g. peas, potatoes, parsnips, carrots, corn
  • All fruit and fruit juice
  • Sweets – baked goods, candy, ice cream
  • Alcohol
  • Saturated fats – e.g. butter, fatty meat, full fat cheese
  • For as long as necessary to reach goal weight
  • Gradual reintroduction of foods
  • Gradual weight loss
As Phase 1 Plus:
  • Medium GI veg and legumes – peas
  • Whole grain – bread, pasta, rice, cereal
  • Low GI fruit
  • Dark chocolate
  • Red wine
  • White carbs – e.g. pasta, bread, rice
  • High GI fruit and veg – bananas, pineapple, potatoes, parsnips
  • Fruit juice
  • Alcohol
  • Sweets - baked goods, candy, ice cream
  • Saturated fats
  • Lifetime maintenance
  • Use GI as a guide to make good choices
  • Go back to phase 1 or 2 if necessary
In this phase you are expected to use the GI as a guide to what to eat and what not to eat - no foods are banned, you should just be more careful with high GI foods and try to choose good fats over saturated fats

south beach diet

While the South Beach Diet does prohibit foods rich in simple carbohydrates, such as white bread and white rice, it cannot be considered low carb as it does not require dieters to forgo carbohydrates entirely or even measure their intake. Instead, it focuses entirely on the glycemic impact of foods, and so many vegetables are permitted even in the first phase, and complex fiber-rich carbohydrates such as brown rice and 100% whole grain bread are permitted in phase 2. Agatston sees the diet as neither low-fat nor low-carb, preferring that dieters learn to choose the right fats and the right carbs. As well as being less restrictive, the diet also does not require you to measure calories or food portions in any way.

Criticisms & Limitations of the South Beach Diet

Unfounded nutrition and health claims

The Journal of General Internal Medicine evaluated the nutrition and health claims made by the South Beach Diet book in 2006 and found that only 33% of the claims made in the book could be confirmed by findings in scientific literature, drawing the fundamental principles and potential for success of the diet into question

Potentially biased reviews

Although two studies have shown favorable results within trials for the South Beach Diet, one of these was by Agatston himself and the other was conducted by Kraft Foods, makers of the South Beach Diet food line. Therefore, in order to draw genuine conclusions about the potential effectiveness of the diet, despite largely unfounded health claims, independent trials would need to be conducted, particularly those that compare the diet to other eating plans over a significant amount of time.

Lack of calorific restrictions

While it could be seen as an advantage that the diet doesn’t involve calorie counting, this can also be a disadvantage as it places few restrictions on the amount of food eaten, which is often the downfall of many people who struggle with their weight. Although teaching people which foods to choose is essential to enabling people to eat healthily for life, there is a potential for confusion with the glycemic index.

Problems with the Glycemic Index

There is also a lot of doubt about the validity of the glycemic index, on which the diet so heavily relies to guide dieters to make good food choices. These include:

  • Lack of validity of GI values:Each food has a GI value, but this can be based on one study performed anywhere in the world or as average of many studies. For example, the GI of peaches is set at 42, a figure which is based on two separate studies – an Italian one which found the GI to be 56 and a Canadian one which showed the average GI as 28.
  • Variety of factors which affect GI:These include the ripeness of fruit (unripe bananas can have a GI of 43, where overripe ones have been clocked at 74), protein content (soy beans have a lower GI than other beans), fat content (peanuts have a very low GI), fiber (orange juice has a higher GI than oranges), and how small the particles are (whole grains have a relatively low GI, but grinding them into flour shoots up the GI), provenance (Australian potatoes have a much higher GI than US ones), and the person eating the food (GI can’t take account of these individual differences).
  • Small range of potential GI scores:The range of possible GI scores is quite narrow so it can be difficult to establish whether a food is ‘good’ or ‘bad’. This is because most of the foods tested have GIs between 40 and 70, and when remembering that GIs are based on averages and not exact numbers, it is difficult if not impossible to tell if any true differences between the majority of the foods exist.
  • Difficult to establish the GI of a mixed meal:The index also only considers food in isolation, however we don’t eat this way. For example, potatoes average a high score of 85, although it is not often that we eat potatoes without some kind of fat or protein, both of which lower the GI of a food.
  • Lack of scientific support that high GI foods are a cause of obesity: Again taking the potato as an example, as well as a high GI, they score the highest of all foods on the satiety index (SI) and are the food that keeps you feeling full for the longest. This calls into question the theory that high GI foods lead to overeating and obesity, and therefore shows little scientific merit for the theory that high GI foods lead to excessive insulin output, which in turn prevents fat burning. In fact, insulin output in response to a meal correlates far better with total calories consumed than it does with the relative GI of the foods in that meal.

Here at we respect that the South Beach Diet meets important criteria for a healthy diet by emphasizing vegetables, fruit, lean protein and whole grains while not omitting any major food group, however we would appreciate more information on how effective the diet is and how easy it is to follow. We can see a potential for confusion, misinterpretation of the glycemic index and accordingly, the over consumption of some foods that may have a low to medium GI, but that should be restricted by amount due to calories. And, while counting calories is not always necessary in the long term to eat healthily, calories should certainly be taken into account when establishing a degree of moderation in food consumption.

Indeed, we believe that moderation is the key to healthy eating, as most foods provide benefits to your health as part of the balanced diet which will help you reach your goal weight with Phen Caps.