A key challenge for researchers and policymakers is to produce and implement evidence-based guidelines for the UK food system to reduce obesity trends. Some 65% of the Scottish adult population is classified as living with overweight or obesity. In general, the Scottish diet is poor quality being too high in calories, processed foods, fats, sugar, and salt; it is equally too low in fibre, oily fish, and vegetables. Poor diets are a major contributory factor driving diet and health inequalities. Diet inequalities are notably socially patterned according to socio-economic status, where overweight and obesity prevalence is higher in socially disadvantaged groups.

Dietary fibre is found inherently in plant derived foods and is indigestible in the small intestine but can be a substrate for fermentation by the microbiota that primarily inhabits the lower gut. This can result in a rise in fermentation products such as short-chain fatty acids which are thought to confer several health benefits, including appetite control and suppression of food intake. Although increased fibre intake can be helpful, it is still a relatively underexploited dietary approach to tackle obesity. Therefore, foods containing fibre, that promote satiety and reduce energy intake, may be promising tools in weight management.

Further, food additives, such as artificial sweeteners or non-nutritive sweeteners, could influence the response to dietary fibre via the gut microbiota, which are tiny bacteria that live in the gut.  There is emerging evidence that some sweeteners could disturb the normal balance of the gut microbial ecosystem. Replacing sugar with non-nutritive sweeteners may inhibit the growth of bacteria for a healthy gut microbiome and may even promote harmful bacteria and/or metabolites. For humans to benefit from dietary fibre, fermentation is essential. This will not happen effectively if additives reduce the beneficial bacteria needed for this process. Furthermore, some non-nutritive sweeteners may prevent weight loss if microbiota disruption adversely affects satiety signalling from the gut. Indeed, reports suggest that some non-nutritive sweeteners are associated with weight gain and obesity as well as disrupted blood sugar control, thereby being potentially as harmful as the sugary drinks they replace.

In Scotland, there is a ‘fibre gap’, with the population consuming well below the recommended levels for good health. It is crucial to explore the reasons for inherently low fibre intake by considering the attitudes of Scottish consumers to dietary fibre and its link to health using a consumer survey approach. Furthermore, there is a need for a move away from a meat-based diet towards increased fibre intake for health reasons, as well as to transition towards a sustainable, environmentally friendly food supply. These issues appear to be being largely missed or ignored by consumers in Scotland.