Overconsumption is manifestly a human problem, whether at the level of individual food intake, which is the primary cause of obesity, or the usage of the world’s natural resources - a driver behind the global climate and biodiversity crises. The way we produce and consume food is one of the major changes that need to be made to mitigate these challenges. There is a general recognition that a reduction in the level of our meat consumption in favour of more plant-based diets would be beneficial.

There is a potential win-win here for both the planet and our health. Plant-based foods are often high in dietary fibre. There is a strong recognition that there need to be higher levels of fibre intake than currently consumed at a population level. However, another important facet of high-fibre diets is that they can act as a natural brake on our food intake, limiting the amount of food we consume and, therefore, weight gain.

There is strong evidence that dietary fibre can suppress food intake and body weight gain in animals. In humans, high fibre intake and microbe diversity correlate with lower long-term weight gain. However, these effects are not always seen and thus a key question is, what determines when the fibre is effective in restraining food intake and body weight gain? To address this question, we need to better understand the importance of different types of fibre and how these fibres act in the gut. There are several theories to explain how fibre restrains food intake, including changes to key bacteria in the gut microbiome, increased levels of short-chain fatty acids (SCFAs) and increased release of the gut hormones that suppress appetite. However, how changes in the gut microbiome are translated into changes in SCFAs to influence gut hormone signalling is still a matter of debate.