Is homemade bread healthier for blood sugar?
It depends on the bread. A slice of white sandwich bread and a slice of slow-fermented sourdough produce very different glucose responses, and the difference isn't small. The flour, the fermentation, and your individual metabolism all matter.
White bread vs sourdough vs wholegrain
White bread is one of the highest-GI foods commonly eaten: refined flour, minimal fibre, fast glucose absorption. Most people see a sharp spike of 3-5 mmol/L within 30 minutes. It's metabolically similar to eating sugar.
Wholegrain bread is better but not always by much. Many commercial "wholegrain" loaves contain mostly refined flour with some grains added. Check the ingredients: if "wheat flour" or "white flour" is first, the glycemic impact is closer to white bread than you'd expect.
Sourdough is where the real difference appears. The long fermentation process (12-24 hours) partially breaks down the starches and produces organic acids that slow glucose absorption. Studies show sourdough produces a 25-40% lower glucose response than white bread of the same weight. Sourdough made with wholegrain flour is the best combination.
Is homemade bread healthier?
It can be, but not automatically. Homemade white bread made with standard flour in a bread machine produces the same glucose spike as shop-bought white bread. The advantage of making your own is control: you can use wholegrain flour, add seeds (which slow absorption), and ferment the dough longer.
A genuine slow-fermented sourdough made at home with wholegrain flour is likely the lowest-spike bread you can eat (apart from bread made using almond flour). But a homemade quick-rise white loaf is metabolically identical to the cheapest supermarket bread.
How to know what your bread does to you
The same bread produces different responses in different people. Some people spike significantly from sourdough; others handle white bread surprisingly well. Gut microbiome composition, insulin sensitivity, and what else you eat alongside the bread all affect the outcome.
A CGM shows your personal response. Nico's coaching helps you interpret it: if bread spikes you, is it the bread itself or the fact that you're eating it without protein? Could switching to sourdough solve the problem, or do you need to change the meal structure? The data answers these questions specifically for your body.
Want to see how your body responds?