Why Do You Lose Belly Fat First on the South Beach Diet?

Losing Weight and Shrinking Your Waist

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Losing belly fat first is a definite plus for those who follow the South Beach Diet. After Phase 1, you will find your pants are quite a bit looser. You may have to take your belt in a notch, cinch the yoga pants tighter, or even have to go shopping for new ones. How can a diet cause you to lose weight in a certain area?

Technically, it's your body's response to the diet — not the diet itself — that leads to the reduction of stomach fat, which is also known a central adiposity. It is very motivating to see positive changes to your body in the first weeks of a diet. This early success in looking better as well as seeing the scale head downward can keep you faithful to the diet guidelines.

How the South Beach Diet Reduces Belly Fat

Dr. Agatston explains the diet's belly-fat-reducing mechanism in the South Beach Diet book. He says that eating diets high in refined sugar and other "bad" carbohydrates spike your blood sugar, leading to higher insulin levels in your body. The increased insulin levels cause fat to be deposited more prevalently in your belly, rather than other areas of the body.

Since the South Beach Diet is all about controlling insulin levels by focusing on "good" carbs and banishing bad ones, making the changes set forth in Phase 1 will lead to a shrinking waistline for those who adhere to the diet.​

Does the South Beach Diet Really Decrease Belly Fat?

Dr. Agatston can make this claim as he has backed it up with a peer-reviewed research study published in the Archives of Internal Medicine. His study compared the South Beach Diet with one recommended to lower cholesterol that didn't restrict carbohydrates. The South Beach Diet group had a significant decrease in waist-to-hip ratio and improvement in blood lipid levels, and almost twice as much weight loss as the other diet group. 

This is much more of a validation of a diet program that is typical for a diet book. The Archives of Internal Medicine publishes serious medical research and it is one of the most noted and respected medical journals. It has stringent guidelines in what it will publish. Very few other diet books can make the same claims as the South Beach Diet. They generally settle for testimonials and, at most, publication in lesser journals that have a less rigorous peer review process.

Dangers of Central Adiposity

Not only does this give your motivation a boost early in the diet, it also provides health benefits: Belly fat has been proven to cause an increased heart disease risk in both women and men. It is associated with insulin resistance and higher levels of inflammation. Studies have shown that high visceral fat mass is associated with increased risk of prediabetes and type 2 diabetes.


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