Is fibre-maxxing (eating as much fibre as possible) healthy?

Eating more fibre is associated in large population studies with a lower risk of cardiovascular disease, type 2 diabetes and colorectal cancer. These are robust associations, observed across tens of thousands of people and in multiple cohorts. The relationship is consistent enough that researchers describe a low-fibre diet as a risk factor in its own right.

Fibre also helps with weight management. Clinical studies and mechanistic research support the idea that fibre suppresses appetite and favourably influences body weight, although exactly how best to deploy it in the context of obesity has not yet been fully worked out. The effect is real, but not large enough for fibre alone to solve an obesity problem.

In the gut, fibre is broken down by bacteria into short-chain fatty acids. These compounds have positive effects on blood sugar regulation, fat metabolism and inflammatory processes. Unprocessed fibre-rich foods, such as wholegrains, legumes, vegetables and fruit, consistently perform best for digestive health in epidemiological research.

But 'as much as possible' is not the same as 'optimal'. The right type and the right amount of fibre for specific gut complaints have not yet been well established. Soluble, viscous and fermentable fibres each have different effects. Fibre is widely used in diverticular disease, but whether it genuinely prevents complications remains unclear. And how your own gut bacteria respond to fibre varies from person to person; a personalised approach is promising, but still far from being practically applicable.

From a practical standpoint: most people in Western countries eat too little fibre and would benefit from eating more. The recommended amount is around 25 to 30 grams per day. Gradually increasing intake through real food, such as beans, oats, vegetables and wholegrains, is proven to be effective and safe. Adding a very large amount of fibre very quickly can temporarily cause gut complaints such as flatulence and bloating. Fibre-maxxing as a trendy extreme therefore has no strong scientific backing over simply eating a good, adequate amount of fibre through wholesome food.