The Sourdough School

BREAD COURSES || NUTRITION TRAINING || DIGESTION ANALYSIS || PERSONALISED BREAD

BAKING WITH THE HANDS OF AN ARTISAN AND THE MIND OF A CLINICIAN

Discover Baking as Lifestyle Medicine, and how to bake Proven Bread, from the walled gardens of Dr Vanessa Kimbell's beautiful Victorian home in rural Northamptonshire, where we train healthcare professionals, teach bakers, and support individuals to bake personalised bread using nutrigenetics and gut health assessments.

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Proven Bread

VANESSA WITH STUDENTS MILLING FLOUR
“Be the change you wish to see in the world.” — Gandhi

WHAT IS PROVEN BREAD™?

Proven Bread™ is a long, slow, naturally fermented, botanically diverse approach to bread, and the breads made this way are called Proven. This approach uses baking as lifestyle medicine and was developed over ten years as the intervention bread in my dietary studies. It is not a style of bread; it is a defined formula designed to deliver minimum levels of fibre, multiple polyphenols, culture fermentation-derived compounds and microbial complexity in a daily loaf that was designed to biohack health through bread. This approach to baking, eating and sharing bread is outlined in the Baking as lifestyle medicine approach and this was the foundation to my intervention bread for my dietary studies and used in both my doctoral research and a nutritional psychiatry project. The formulation, fermentation and botanical diversity were chosen because they support measurable shifts in microbial, metabolic and behavioural markers. Proven is the bread itself – and this can be applied to any formula as a clinically informed, evidence-based everyday bread that reconnects soil, farmer, miller, baker and eater, and turns the act of eating bread into system change

PROVEN BREAD

Proven Bread is a standard, not a recipe — “can be applied to any formula” means Proven is a replicable protocol that can scale and be licensed, not a single product

Dual definition — Proven is both the approach and the bread itself. That’s legally tight and conceptually elegant – designed to make the point that’s is an evidence based long slow proven bread that is biochemically transformed by real fermentation.

Measurable criteria — minimum fibre levels, multiple polyphenols, cultured fermentation-derived compounds, microbial complexity. These are auditable, defensible standards

Proven Bread has a Clinical foundation — doctoral research, nutritional psychiatry project, dietary studies. This isn’t wellness marketing, it’s evidence-based

It is grounded in Systems change  — soil, farmer, miller, baker, eater. Proven is a bread defined by the relationships it has as a supply chain intervention, not just a product

“Biohack health through bread” — takes complex science and makes fibre, minerals and transformation in fermentation accessible to people without dumbing it down“Turns the act of eating bread into system change” — elevates a daily habit into something with meaning and impact for nourishing bread as social justice.

Proven Bread™ is the loaf at the centre of my work: a long-fermented sourdough made with Botanical Blend flour (30+ plants), around 18 hours’ fermentation and approximately 6 g of fibre per slice. It took a decade to develop and was used as the intervention bread in my BALM Protocol dietary studies and doctoral research, where it was associated with measurable shifts in mental-health and gut-health markers. Proven Bread is not just “better bread”; it is a designed tool for system change – reconnecting soil, farmer, miller, baker and eater, and reshaping how we bake, eat and share bread.


3. WHAT IS PROVEN BREAD™?

Proven Bread™ is a specific sourdough formula that took ten years to develop. It is the bread I teach at The Sourdough School, and it is the bread used as the intervention loaf in my BALM Protocol dietary case studies, my doctoral research, and a nutritional psychiatry project. When I say “Proven”, I am not talking about a vague category of healthy bread. I am talking about this loaf.

It is a long-fermented, botanically diverse sourdough baked with Botanical Blend flour – over thirty different plant ingredients – and around 18 hours of live-culture fermentation. Each loaf is pre-sliced into 24 slices, delivering roughly 6 g of fibre per slice, made from regeneratively grown British grains and botanicals, stone-milled and hand-blended. There is no synthetic fortification; the functionality comes from the grain, the plants, and the fermentation.

During my doctorate, Proven Bread was analysed in the lab and compared to standard white and wholemeal loaves. The analysis showed nearly three times more polyphenols than wholemeal bread and around eight times more than white bread, along with two to three times the antioxidant activity and ten polyphenols not detected in standard breads, including caffeoylcholine. This is not marketing language; these are measured differences in the biochemical profile of the bread.

Proven Bread was then used as the single dietary intervention in my 12-week studies. Participants ate this bread in a structured way and tracked changes in their mood, digestion, sleep, satiety and other symptoms, alongside microbiome testing in some cases. The studies reported measurable improvements in mental-health markers and gut-health indicators. Most research loaves never leave the lab or the paper they’re written on; Proven Bread does both. It is the same loaf you can learn to bake or receive through the Proven programme.

But Proven Bread is more than a research project. It is a piece of system change you can hold in your hands.

The formula was designed to reconnect the parts of the food system that have been fragmented: soil, farmer, miller, baker and the person who eats or bakes the bread. It is a transdisciplinary project – bringing together clinical evidence, microbiology, nutrigenetics, fermentation, regenerative agriculture and craft baking – and flattening them into one accessible, shared object. It biohacks bread in the truest sense: using fermentation, botanical diversity and structure to support the gut–brain axis and metabolic regulation, while remaining an everyday, eatable loaf.

Proven Bread reshapes how you bake, eat and share bread. It invites bakers, clinicians and home cooks into the same system: farmers growing grain for health, millers creating Botanical Blend, bakers fermenting and baking with intention, and people eating bread that has been formulated with their physiology, not just machinery, in mind. It is an empowerment tool as much as it is a food – a way for ordinary people to participate in system change, slice by slice.

This is not a patch on a broken system.
Proven Bread is a prototype of a different one.

What happens when everyday bread is designed with human biology in mind?

This is Proven Bread™.

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All reasonable care is taken when advising about health aspects of bread, but the information that we share is not intended to take the place of treatment by a qualified medical practitioner. You must seek professional advice if you are in any doubt about any medical condition. Any application of the ideas and information contained on this website is at the reader's sole discretion and risk.

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