Fibre-fortified foods trimmed weight and cholesterol, and under 15 g a day was enough

Much of the modern diet is built on processed and refined foods that have had their fibre stripped out, a shift the authors link to the global prevalence of obesity and cardiometabolic disease. One proposed fix is not to change what people eat but to change what is in it: adding fibre back into the processed foods people already buy. Whether that fortification actually shifts body composition, blood lipids, blood pressure and blood sugar control, rather than just looking good on a label, is the question this review set out to answer.

The researchers searched five databases for randomised controlled trials testing foods fortified with dietary fibre, and 31 trials made the final analysis. Outcomes covered body composition, blood pressure, the blood lipid and lipoprotein panel, and glycaemic markers such as fasting glucose and HbA1c. Changes were pooled using a random-effects model. The team also ran subgroup analyses splitting results by fibre type, by whether the food was solid or liquid, and by whether fortification was below or at least 15 g per day, plus regression analyses to check for dose effects.

Fibre-fortified foods significantly reduced body weight, fat mass, total cholesterol, LDL cholesterol, triglycerides, fasting glucose and HbA1c. Fibre type mattered: soluble fibre significantly reduced triglycerides and insulin, while insoluble fibre reduced body weight, BMI and HbA1c. Solid and semi-solid foods produced greater improvements than liquids. Counter-intuitively, fortification below 15 g per day showed more benefits than 15 g or above, although waist circumference did improve in a dose-dependent way. Blood pressure was among the outcomes evaluated but was not listed among the significant improvements.

The benefits of fibre from whole foods are well established; this review extends the case to fibre deliberately added back into processed products, which is a more realistic route for many modern diets. The dose finding complicates the assumption that more is always better, and the solid-versus-liquid split suggests the format of the food matters as much as the fibre itself. Open questions remain about which specific fibres work best, how long benefits persist, and whether fortified products can match the effects of naturally fibre-rich diets.

This is a reason to think that fibre-fortified versions of everyday foods can do more than pad a nutrition label: across 31 trials they moved real markers including weight, fat mass, cholesterol and long-term blood sugar. It also suggests the format matters, with solid foods outperforming fibre-fortified drinks, and that moderate additions performed at least as well as large ones. None of this replaces a diet rich in naturally fibrous foods, but it indicates the fortified route is not an empty gesture.