Key takeaways:
- Most Brits eat bread daily but underestimate how many additives and preservatives are typically used in standard sliced loaves.
- Rye stands out nutritionally, with strong evidence linking it to better glycemic control, improved lipid markers and positive gut health effects.
- Rye January reflects a broader shift toward ingredient awareness and fermentation-led breadmaking rather than avoiding bread altogether.
Ask most people what’s in bread and you’ll usually get the same answer: flour, water, salt, yeast. That assumption, however, doesn’t hold up particularly well. New consumer research shows that most Brits have little understanding of what actually goes into the sliced bread they eat every day.
The research was commissioned by organic food brand Biona to underpin its Rye January campaign, which encourages consumers to swap standard sliced bread for rye during January. The aim isn’t to get people to avoid bread or undergo a dietary overhaul. Its message is to get them to look more closely at ingredients, fermentation and how bread is made.
According to the YouGov survey, 73% of respondents can’t identify the most common additives and preservatives used in everyday bread, with 93% unaware that an average sliced loaf can contain up to 19. Each plays a role in large-scale bread production, ranging from emulsifiers to improve texture and shelf life, to preservatives that slow mold growth and enzymes used to speed up dough processing, alongside acidity regulators, flour treatment agents, added sugars and stabilizers.
Further research found that almost half of respondents are concerned about what’s really in their bread, while a growing share say they’re checking ingredient labels more closely.
Why rye behaves differently
Backing the campaign is Dr Rupy Aujla, a practicing GP, author and founder of The Doctor’s Kitchen. His interest in bread isn’t ideological; it’s practical. Foods eaten every day tend to add up over time. Rye, he says, is often misunderstood.
“Rye is nutritionally distinct from other grains like wheat and spelt due to its higher content of dietary fiber (notably fructans and β-glucans) and unique phenolic acids,” he explains. “Rye’s fiber profile is also more fermentable, supporting your gut microbes, which is linked to improved metabolic health risk markers. It also keeps you fuller for longer, which means you’re less likely to overeat.”
Randomized controlled trials and meta-analyses show wholegrain, high-fiber rye bread leads to lower post-meal insulin responses and improved insulin sensitivity compared with refined wheat products, without significantly affecting fasting glucose.
A 2025 systematic review and meta-analysis published in Nutrition & Metabolism reinforced what researchers often call the ‘rye factor’ – a consistent metabolic response seen across multiple studies.
Rye intake has also been linked to improved blood lipid markers, including lower LDL cholesterol, triglycerides, and apolipoprotein B – a measure increasingly used to assess cardiovascular risk. Those findings appear in The American Journal of Clinical Nutrition and are echoed by more recent research, including the RyeWeight Study published in Nutrients in 2022.
“In short, rye could be beneficial for both metabolic health and heart health,” says Dr Rupy. “I personally love the flavor, as well as the shorter ingredients list and it’s great for open sandwiches.”
Fermentation and ingredients
The ingredient gap highlighted by the research isn’t just about nutrition. It’s also about process.
“Rye’s natural structure and fermentation behavior, especially in sourdough processes, enable shorter, cleaner ingredient lists,” adds Dr Rupy. “There does appear to be less need for additives such as dough conditioners, emulsifiers, or added sugars, but every brand and baker’s method of bread making is different.”
Rye allows fermentation and acidity to do more of the work. From a baking standpoint, that comes with trade-offs.
“Rye doughs are different from wheat due to lower gluten content and higher soluble fiber levels. They’re stickier, less elastic, and rely on acidification to stabilize structure, resulting in denser, moister loaves with longer shelf life.”
That difficulty is part of why rye slipped out of mainstream breadmaking as production scaled up. It’s also why it’s being revisited.
After January
Rye is back in focus as expectations around ingredients shift. “Rye and sourdough-style breads represent a strategic opportunity for bakeries to offer minimally processed, fiber-rich products,” asserts Dr Rupy. “These breads can be positioned as evidence-based alternatives to conventional sliced bread.”
Fermentation and gut health are also getting closer scrutiny. A 2023 study published in Molecules looked at how rye dietary fiber behaves when fermented with probiotic microorganisms, finding that rye’s fiber structure supports higher production of short-chain fatty acids – compounds linked to gut health and metabolic regulation – while also encouraging the growth of beneficial bacteria. The authors noted that fermentation changes how rye fiber interacts with the gut, helping explain why rye-based breads are often associated with better digestive tolerance and longer-lasting satiety.
On Rye January itself, Dr Rupy’s focus is on continuity. “The key message for bakers during campaigns such as Rye January should be: ‘Choose rye for its unique health benefits and distinct flavor. Make it a staple, not just a seasonal choice. Reinforcing the evidence for metabolic, heart, and gut health benefits, and highlighting the clean-label, minimally processed nature of rye breads can encourage sustained consumer adoption beyond January.’”
Bread doesn’t need to disappear from the diet. But it does deserve a closer look. Rye January is one way of starting that conversation.
Biona’s rye bread, made using a traditional fermentation process with four organic ingredients, is available at Tesco, Ocado, independent health food stores and online, with an RRP of £2.69.
Studies:
Ghazvini M, Ghanbari-Gohari F, Foshati S, Akhlaghi M. Effect of rye consumption on markers of glycemic control: evidence on the “rye factor”: a systematic review and meta-analysis of randomized controlled trials. Nutr Metab (Lond). 2025 Mar 31;22(1):27. doi: 10.1186/s12986-025-00901-8. PMID: 40165312; PMCID: PMC11956258.
Eriksen AK, Brunius C, Mazidi M, Hellström PM, Risérus U, Iversen KN, Fristedt R, Sun L, Huang Y, Nørskov NP, Knudsen KEB, Kyrø C, Olsen A, Tjønneland A, Dicksved J, Landberg R. Effects of whole-grain wheat, rye, and lignan supplementation on cardiometabolic risk factors in men with metabolic syndrome: a randomized crossover trial. Am J Clin Nutr. 2020 Apr 1;111(4):864-876. doi: 10.1093/ajcn/nqaa026. PMID: 32097450.
Iversen KN, Dicksved J, Zoki C, Fristedt R, Pelve EA, Langton M, Landberg R. The Effects of High Fiber Rye, Compared to Refined Wheat, on Gut Microbiota Composition, Plasma Short Chain Fatty Acids, and Implications for Weight Loss and Metabolic Risk Factors (the RyeWeight Study). Nutrients. 2022 Apr 17;14(8):1669. doi: 10.3390/nu14081669. PMID: 35458231; PMCID: PMC9032876.
Koj K, Pejcz E. Rye Dietary Fiber Components upon the Influence of Fermentation Inoculated with Probiotic Microorganisms. Molecules. 2023 Feb 16;28(4):1910. doi: 10.3390/molecules28041910. PMID: 36838898; PMCID: PMC9958741.
