Nutrition literature abounds with odes to the many benefits of including liberal amounts of dietary fibre in your diet.
Apart from helping normalize bowel movements and reducing the risk for hemorrhoids and diverticulosis, more fibre may also reduce cholesterol levels, slow carbohydrate digestion, and perhaps even reduce risk for colon cancer (although the research on the latter remains disappointingly inconclusive).
Notably increasing fibre intake has also been promoted as a means to help manage body weight. Various mechanisms have been discussed for this, including increasing satiety, reducing the glycemic index of foods, and changing gut flora to favourably affect energy homeostasis.
But how effective is dietary fibre intake really in preventing weight gain?
This question was now examined in the perhaps largest study on this topic to date just published by Huaidong Du and colleagues from the National Institute for Public Health and the Environment, Bilthoven, Netherlands, in the American Journal of Clinical Nutrition.
The relationship between body weight and fibre intake was studied in a prospective cohort of 89,432 European participants, aged 20-78 y, who were free of cancer, cardiovascular disease, and diabetes at baseline and who were followed for an average of 6.5 y. Adjustments were made for follow-up duration, other dietary variables, and baseline anthropometric, demographic, and lifestyle factors.
Overall total fibre was inversely associated with subsequent weight and waist circumference change with a 10-g/day higher total fibre intake associated with about 40 g (~1.4 oz) less weight gain and 0.8 mm (~3/100 of an inch) less waist circumference per year. Interestingly most of this effect was apparently due to cereal fibre (largely insoluble) than to fruit or vegetable fibre (largely soluble).
The authors enthusiastically conclude that their study may support a beneficial role of higher intake of dietary fibre, especially cereal fibre, in prevention of body-weight and waist circumference gain.
I, in turn, am not looking to fibre as the next weight-loss panacea. Yes, eating lots of fibre may have some beneficial metabolic effects, but don’t count on it as the panacea for countering the obesity epidemic.
In fact, with beneficial effects of dietary fibre weighed in ounces and fractions of an inch, this fuss about fibre seems more like too much ado about nothing than a meaningful approach to weight management.
Obviously, the study tells us nothing about the effectiveness of using fibre in conjunction with a weight management program or about taking “pharmacological” doses of commercial fibre extracts often sold as weight-loss supplements - but I have yet to see totally convincing data on either.
For now, let’s stop obsessing about fibre intake for weight management and focus on what really matters: calories.
AMS
Edmonton, Alberta
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