Fiber for Breakfast!

Studies have shown that those who eat more fiber have a reduced risk of obesity and type 2 diabetes, but it's not clear whether this is an effect of the fiber itself, nor what type of fiber has this effect.

Scientists at the University of Toronto devised a study to compare the effects of different types of fiber on appetite and blood glucose levels (Am J Clin Nutr 2007;86(4);972-9). They recruited 31 healthy young men in the normal-to-overweight range to participate in their feeding study, which took place on a weekly basis for four weeks.

Each subject was served one of four meals between 7 and 10am (breakfast): a high-fiber breakfast cereal in milk (with water to drink), a low-fiber breakfast cereal in milk (with water to drink), white bread with milk on the side (as well as water to drink), or just water. The three food meals yielded the same amount of calories. Before and after the breakfast meal the subjects completed a survey assessing their level of hunger and a blood sample was taken to test blood glucose levels.

After finishing the breakfast meal, these measurements were taken again at 15-minute intervals until one hour had passed, at which time the men were given water and several mini-pizzas of their favorite kinds - as much as they wanted - and were instructed to eat until they were comfortably full. How much they ate was recorded, and again their level of hunger was assessed both before and after the meal. Their blood glucose levels were also taken at fifteen-minute intervals for an hour after finishing the pizza meal.

The researchers found that those who ate the high-fiber cereal or the white bread ate less at the pizza meal than those who ate the low-fiber cereal. The subjects' appetite levels, fifteen minutes after eating the high fiber cereal, were much lower for those who ate the high-fiber cereal, followed by the low fiber cereal, then the white bread, then (of course) the water. The higher fiber meals also helped keep the subjects' blood glucose levels more stable after their meals.

What this means for you

Whether you're diabetic or not, eat your breakfast - it doesn't have to be a big one. Eating a high fiber cereal (they used Fiber One) at breakfast will help you feel less hungry at lunch. We do wish they'd included whole wheat bread in their test breakfast, but if you look there are high-fiber breads available. Compare the fiber levels of your favorite cereals or breads and pick the one that will keep you feeling fuller longer.

First posted: October 17, 2007