A recent study has turned the bread world upside down, revealing that the type of bread you choose can drastically impact your blood sugar, metabolism, and overall health.

While many people may shy away from bread, fearing it could derail their weight loss or well-being, the research shows that not all breads are created equal.

Sourdough bread, in particular, has been shown to offer incredible benefits that white and whole wheat breads simply can’t match. With its ability to stabilize blood sugar and improve insulin response, sourdough could be the secret ingredient for better meals and healthier living.

So, what’s the science behind sourdough, and how can it help you live a healthier life? Let’s dive in and take a closer look at why this age-old bread might be your best breakfast choice.

Research Overview

Professor Terry Graham conducted research on four different types of bread to assess their impact on carbohydrate metabolism, blood sugar, and insulin levels

"There’s a common belief that avoiding bread is essential for weight loss," said Graham, a professor in human health and nutritional sciences. "In reality, bread is a major source of grains and offers several health benefits. This study aimed to identify which breads provide the most advantages, allowing us to enhance these benefits in a single loaf."

Types of Bread Studied

The research compared white bread, whole wheat, whole wheat with barley, and sourdough white bread. Graham and his team measured how participants responded after eating these breads for breakfast and again after a standard lunch.

Subjects, aged between 50 and 60 and classified as overweight, exhibited the most favorable responses after consuming sourdough white bread. Notably, these positive effects persisted even after a subsequent meal that did not include bread.

Findings on Blood Sugar and Insulin

"Sourdough resulted in lower blood sugar levels alongside a similar increase in insulin," Graham noted. "Interestingly, these benefits continued into the second meal and lasted for several hours afterward. This indicates that breakfast choices can significantly affect lunch responses."

Graham suggested that the fermentation process in sourdough alters the starches, making the bread more beneficial. While sourdough ranked highest in the study, the whole wheat varieties performed the worst—lower than even white bread.

Whole Wheat vs. Sourdough

The whole wheat breads caused significant spikes in blood sugar levels, which remained elevated long after lunch. Graham explained that these adverse effects may stem from the milling process used for the whole wheat bread tested, which resembles that of white bread.

He clarified that not all whole wheat or whole grain breads are created this way. "The nutritious parts of the grain, such as wheat germ and bran, are removed when making white flour and only partially added back for whole wheat. Our research indicates that the best way to obtain these nutrients is through whole grain bread instead of just whole wheat."

Future Research

Supported by the Ontario Ministry of Agriculture, Food and Rural Affairs, Graham's findings have prompted further investigation into the health advantages of sourdough and whole grain breads. In partnership with Stonemill Bakehouse in Scarborough, the team has developed a whole grain sourdough bread and is currently studying its long-term health effects, comparing results to those obtained from standard white bread.