A recent study published in the Journal of Nutrition has found that during weight loss, those who increase their fiber intake the most lost the most weight and are also able to stick to their recommended diet plan more effectively than people who do not increase their fiber intake.
In the POUNDS Lost (Preventing Overweight Using Novel Dietary Strategies) study, 345 people were assigned to follow one of four diets varying in fat, protein, and carbohydrate content for 6 months.
The average weight loss during the study was 7.3 kilograms (18.5 pounds), which varied based on energy density of the diet, age, and other factors. The most influential predictor of weight loss, though, was fiber intake.
The study showed that the people who increased their fiber intake the most (>8 grams per day more than what they consumed when they started the study) lost around 78% more weight than people who decreased their fiber intake (10.3 kg vs 5.8 kg weight loss).
The authors suggest that fiber isn’t causing the weight loss itself, but instead making the weight loss more effective and helping participants stick to their prescribed diet plan. They mention that fiber may be acting in a few ways, such as promoting satiety and fullness, making it harder for the body to absorb calories from the food we eat, and reducing caloric density of foods participants selected.
Key takeaways about fiber
Fiber is consistently shown in science to have a variety of health benefits, including digestive health, heart health, blood sugar management, weight loss, and even immune function. Few people consume enough fiber compared to recommendations, though. For example, in the US, only ~6% of people meet daily recommendations for fiber.
At the same time, popular weight loss diets like the ketogenic diet place severe restrictions on carbohydrate intake, which also limits the amount of fiber someone on the diet can eat.
Finding new ways to make fiber convenient for all people to eat more of, not just those on weight loss diets, is key to improving health. For some populations, this could mean making fruits, vegetables, and whole grains more accessible or affordable. For others, it might mean finding new ways to incorporate these high fiber foods into food or beverage products to make them more convenient and in line with consumer taste expectations. Those on the ketogenic diet or making products to comply with the diet should consider adding fiber where possible, while staying within the recommended carbohydrate limits of the diet.