KHNI: Optimizing fibermaxxing for gut health with fiber diversity and smart reformulation

Social media is bringing gut health to the forefront, with the “fibermaxxing” trend shaping the younger generation’s approach to food. An article on the Kerry Health and Nutrition Institute (KHNI) website by independent nutrition and regulatory consultant, Dr. Yvonne Finnegan, states that the trend is helping dietary fiber finally get the spotlight it deserves by highlighting both the wide range of health benefits of fiber and easy and appetizing ways to increase intake.

Nutrition Insight speaks with a senior nutrition scientist at the KHNI, who discusses the fiber gap, risks of fiber overconsumption, the importance of fiber diversity, and reformulation solutions.

Registered nutritionist and chartered scientist, Dr. Aisling Aherne, says, “Fibermaxxing trends have much potential to close the fiber gap — where research shows many people, especially in the West, are not meeting recommended levels. Dietary fiber recommendations vary globally between 25–40 g/day for adults, but dietary surveys show that large proportions of the population are not meeting these targets.”

“Scientific evidence strongly associates optimal fiber intake with reduced risks of cardiovascular disease and several cancers, especially colorectal cancer, as well as improved metabolic and gut health, so many people are missing out on the benefits,” she adds.

The KHNI article points out that while some fibermaxxing posts encourage a healthy fiber intake from natural fiber sources, others “gamify” it to “max out.” Here, the health messaging takes a turn, as “overmaxxing” fiber may actually cause short-term digestive issues and put consumers off.

Aherne agrees, stating that, “From a scientific perspective, side effects can begin when fiber intake exceeds the gut’s physiological tolerance (up to 50 g/day), especially when intakes are highly concentrated and/or rapidly increased.”

The tolerance to individual isolated or added fibers can also differ and needs to be considered. She also notes that when fiber intake is low, gradually increasing consumption is better to avoid experiencing gut issues such as bloating, cramping, constipation, and diarrhea. Additionally, people should be careful when taking fiber supplements, as they could easily consume too much.

Fiber diversity

Discussions should not just focus on fiber quantity, as fiber diversity is also important for achieving different health benefits, says Aherne. 

Dr. Aisling Aherne, senior Nutrition Scientist at Kerry Health and Nutrition Institute (KHNI).

She notes that some fiber “maxxers” take supplements to meet recommended fiber levels. However, supplements alone do not bring the benefits compared to increasing fiber diversity.

“The term ‘dietary fiber’ refers to a large group of complex structures that deliver a wide range of functions, such as for heart, metabolic, gut, and/or potentially mental health,” explains Aherne.

“For instance, fibers from wheat bran promote good bowel function, and oat beta-glucan fibers reduce LDL cholesterol, often called ‘bad’ cholesterol, whereas certain fibers also act as a food source for the gut microbiota, which produce metabolites that can be beneficial to health.”

Soluble fiber helps slow digestion, control blood sugar, and lower cholesterol, and is found in foods like oats, nuts, beans, and apples. 

Meanwhile, insoluble fiber remains unchanged when digested, preventing constipation, and is found in whole wheat flour, nuts, seeds, and vegetable skins. This fiber binds water in the large intestine, meaning more fluid is required for the fiber to work properly.

In her KHNI article, Finnegan suggests that, while counting fiber intake can be a useful aspect of the fibermaxxing trend and help people discover good food sources of fiber, it is important not to get too obsessed and to focus on embedding good long-term dietary habits. Additionally, she stresses that social media posts should go beyond sharing messages of regular bowel movements and instead inspire tasty recipes to help dispel the myth that fiber is bland and boring.

Previous research on TikTok’s impact on younger consumers’ diets and food habits found that visually appealing, dynamic food content has a stronger influence on young users’ diets.

Recently, experts urged recognition of fiber as an essential nutrient for reducing chronic disease risk.

Reformulation considerations

Aherne explains that fiber can be used to replace sugar or fat in some food categories, as it provides 2 kcal/g (depending on local regulations). It can also reduce the energy value when substituting for carbohydrates (4 kcal/g) or fat (9 kcal/g). Many high-fiber products rely on fiber to reduce sugar or calories. Aherne explains that, for formulation, manufacturers should factor in regulations concerning fiber alongside allergen information.

Diverse fibers — from oats to beans — unlock gut, heart, and metabolic benefits beyond simple quantity goals.

“Additionally, when adding fiber to foods, manufacturers should consider the overall nutritional profile, as consumers increasingly question products that offer a nutrition or health claim but contain high levels of sugars, saturated fat, and/or salt.” 

“Therefore, manufacturers aiming to make fiber claims should assess whether broader reformulation of sugars, saturated fat, salt, or portion size adjustment is needed to maintain consumer credibility,” she explains.

According to this year’s nutrition innovation trends, fiber and protein are set to dominate, driven by consumer demand for multifunctional, convenient products that support gut health and satiety. Nutrition Insight previously spoke with FrieslandCampina Ingredients and Lonza Capsugel about opportunities for fiber formulation.

Additionally, Aherne says that manufacturers should aim to balance their formulations’ efficacy with consumer experience targets. She notes that, depending on the added fiber, it may be better to add a smaller but tolerated amount of fiber, rather than aiming for a higher amount to meet a “high fiber” claim, but risks being poorly tolerated and not purchased again.

“In many cases, combining multiple fiber types may improve both tolerance and help consumers hit their fiber targets.”