Moderation, not type, matters most in bread choices

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Moderation, not type, matters most in bread choices

Published: 22 May. 2025, 00:05

Audio report: written by reporters, read by AI

Jung Jae-hoon

The author is a pharmacist and food writer.

As interest in slow aging and healthy eating habits continues to grow, people are becoming increasingly selective about what they eat — including bread. Many now scrutinize ingredients before choosing a loaf, believing that whole grain or sourdough bread is significantly better for blood sugar control than white bread. Yet research shows that the difference in health impact may be less substantial than widely assumed.

A 2023 meta-analysis by researchers in Austria found no clear evidence that consuming sourdough bread leads to reduced risk of diabetes or more effective weight control. This runs counter to the common belief that fermented breads with lactic acid bacteria or yeast offer superior health benefits over those made with refined flour.

A freshly-baked loaf of sourdough bread [AP/YONHAP]

Part of the explanation may lie in how individuals metabolize carbohydrates differently. A 2017 study by a team in Israel tested participants by rotating their consumption of white bread and sourdough over a controlled period. The researchers found no significant differences in major health indicators — such as blood pressure, blood glucose levels, body weight or cholesterol — between the two types of bread.

However, they did observe that the glycemic responses varied among individuals. Some participants experienced smaller blood sugar spikes with white bread, while others responded better to sourdough. These variations were attributed to differences in gut microbiota. The findings suggest that personalized dietary approaches may be more effective than broad dietary guidelines, particularly for those managing conditions like diabetes.

Still, the overall effect of bread type on health appears to be minor. While some studies have reported that sourdough may help moderate post-meal blood sugar levels, others have highlighted similar effects from whole wheat bread. In contrast, a 2008 Canadian study found that certain whole grain breads caused quicker spikes in blood glucose than white bread.

These conflicting results underscore a key point: The impact of bread on health indicators like blood sugar, blood pressure and weight tends to be inconsistent and relatively small. This may explain why broad nutritional guidance does not emphasize one type of bread over another.

Ultimately, the more critical factor is not what type of bread is consumed, but how often and how much is eaten. Regardless of whether it is sourdough or whole wheat, overconsumption can lead to elevated blood sugar levels and weight gain. In the context of the growing popularity of slow-aging diets and wellness foods, this means that marketing claims about specific ingredients should be viewed with caution.

Even if a certain type of bread causes a slightly slower rise in blood sugar, the difference may be negligible when portion sizes and frequency of consumption are not controlled. Rather than chasing food trends, building healthy eating habits begins with balance and moderation.

Translated from the JoongAng Ilbo using generative AI and edited by Korea JoongAng Daily staff.