ZOE runs the largest nutrition science study in the world. We analyze how different people respond to thousands of foods and publish this research in top scientific journals, including Nature Medicine.
Our scientists have found that white bread is not the best bread for most people.
Based on measurements of over 20,000 individuals, our scientists predict that for 55% of people, it’s best to only eat white bread once in a while and in small quantities.
That’s because white bread is a processed food with low-quality carbs and can contain added sugar. Eating white bread can cause large blood sugar spikes, which are not good for your health.
For the remaining 45%, it’s OK to enjoy white bread in moderation — around 2-3 times per week — but not daily, and large quantities may have a negative impact.
At ZOE, we know that everyone responds differently to food.
You can take a free quiz to learn more about finding the best foods for you with our personalized nutrition program.
Read on to discover why white bread is not a good choice for many people.
White bread and blood sugar
When you eat food that contains carbohydrates, your body breaks these down into simple sugar, or glucose. This is absorbed into your blood, leading to a rise in your blood sugar.
Your cells take in glucose from your bloodstream, with the help of a molecule called insulin, so that they can use glucose for energy. As your cells absorb glucose, your blood sugar levels fall.
Changes in blood sugar levels after eating are normal. Complex carbohydrates like whole grains cause a gradual rise and fall in blood sugar. Foods with simple sugars can cause sharp spikes and falls in blood sugar.
This can make you feel hungry again soon after eating and is not good for your health long-term.
How much your blood sugar rises after you eat white bread is unique to you, and factors like your sex and age are involved.
Based on our research, white bread is likely to cause large blood sugar spikes in just over half of the population.
White bread and gut health
The trillions of bacteria and other microbes that live in your gut make up your gut microbiome. They help digest your food and are important for your immune system and your overall health.
The bacteria in your gut can use fiber as fuel and turn it into chemicals that are good for your body. White bread has, on average, 0.6 g of fiber per slice, which is a very low amount.
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ZOE scientists have found 15 “good” gut microbes that are associated with indicators of good health and 15 “bad” gut microbes that are linked with worse health.
White bread isn’t great for several of the “good” bugs, including Freddy, Oscar, and Claude, and is likely to promote more of the “bad” bugs that you have in your gut.
How our scientists measure if a food is good for you:
We measure the responses of thousands of people to different foods by collecting data about blood sugar and blood fat levels, the gut microbiome, inflammation, exercise, sleep, and more.
After you take our simple at-home test, we use artificial intelligence to compare the results to those of over 20,000 people who have taken part in our clinical studies.
Based on your unique data, we can score any food or meal as being good or not so good for you.
White bread and your body: It’s personal
Our research shows that how your body responds to the foods you eat is unique to you. Your blood sugar and blood fat metabolism, as well as your unique gut bugs, influence this.
With the ZOE program, you can find out exactly how good white bread is for you and your long-term health goals. And if it turns out that it’s not great for you, we’ll suggest plenty of food swaps to help you find the best foods for your body.
Take our free quiz to find out more.
What could you eat that’s better?
Try swapping white bread for whole-grain bread, as this scores better than white bread for your health. Store-bought whole-grain bread is still a processed bread, but it has more fiber than white bread, which makes it a better option for your gut microbes.
Ready to learn about the best foods for you?
Bread, white, commercially prepared. (n.d.). https://fdc.nal.usda.gov/fdc-app.html#/food-details/325871/nutrients
Microbiome connections with host metabolism and habitual diet from 1,098 deeply phenotyped individuals. Nature Medicine. (2021). https://www.nature.com/articles/s41591-020-01183-8