Researchers tested three types of whole grain bread to see which one keeps you full longer and affects blood sugar differently. They studied 44 healthy young adults who ate different breads for two weeks each. The breads were made with regular yeast, sourdough starter, or both. While there were small differences in how slowly people ate the bread and how full they felt, all three types had very similar effects on hunger levels and how much people ate at their next meal.

The Quick Take

  • What they studied: How three different types of whole grain bread affect hunger, fullness, and blood sugar levels
  • Who participated: 44 healthy young adults with an average age of 25 and normal weight
  • Key finding: All three bread types had nearly identical effects on how much people ate at their next meal, despite small differences in eating speed and fullness
  • What it means for you: You can choose any whole grain bread based on taste preference - they all seem to affect hunger and blood sugar similarly

The Research Details

This was a carefully controlled study where each person tried all three bread types in random order. Participants ate 180 grams of one type of bread daily for two weeks, then took a two-week break before trying the next type. On the final day of each bread period, researchers measured how the bread affected their body by tracking blood sugar, hunger hormones, and how much they ate at lunch afterward. Neither the participants nor researchers knew which bread was being tested during each period, which helps ensure unbiased results.

This crossover design is considered the gold standard for nutrition studies because each person serves as their own comparison, eliminating individual differences that could skew results. The two-week periods allowed enough time for any effects to show up.

The study used proper blinding, randomization, and crossover design with adequate washout periods. However, the sample was limited to young, healthy adults with normal weight, so results may not apply to older adults or people with health conditions.

What the Results Show

The main finding was that all three bread types led to similar lunch portions - people didn’t eat significantly more or less after any particular bread. This suggests that the type of fermentation (yeast vs. sourdough) doesn’t meaningfully change how filling whole grain bread is over several hours. Blood sugar responses were also very similar between the three breads, with only minor differences that probably aren’t meaningful in real life. The researchers measured various hunger hormones and found no major differences between bread types.

There were some small differences in how people experienced eating the breads. Regular yeast bread and the combination yeast-sourdough bread were eaten more slowly than pure sourdough bread. People also reported feeling slightly more satisfied after eating these two types compared to sourdough alone. However, these differences were small and didn’t translate into eating less at the next meal.

Previous studies have suggested sourdough bread might have better effects on blood sugar and satiety, but this study found minimal differences. This could be because whole grain bread already provides benefits that mask differences between fermentation methods, or because the specific sourdough cultures used here behaved differently than in other studies.

The study only included young, healthy adults with normal weight, so we don’t know if results would be the same for older people, those with diabetes, or people who are overweight. The study periods were also relatively short at two weeks each, so longer-term effects remain unknown.

The Bottom Line

Choose whole grain bread based on your taste preferences rather than expecting major differences in hunger control or blood sugar effects. All three types appear to provide similar benefits for appetite regulation and metabolic health.

This research is most relevant for healthy adults looking to optimize their bread choices. People with diabetes or other metabolic conditions should still consult their healthcare provider about the best bread options for their specific needs.

The effects measured in this study occurred within hours of eating, so you can expect similar immediate responses regardless of which whole grain bread type you choose.

Want to Apply This Research?

  • Track your hunger levels 2-4 hours after eating different types of whole grain bread to see which works best for your individual response
  • Focus on choosing any whole grain bread over white bread, and pay attention to eating speed and chewing thoroughly for better satiety signals
  • Log your bread type and portion size along with hunger ratings before your next meal to identify personal patterns over time

This research involved healthy young adults and may not apply to individuals with diabetes, digestive issues, or other health conditions. Consult with a healthcare provider or registered dietitian for personalized dietary advice, especially if you have medical conditions that affect blood sugar or digestion.