Can Fiber Undo the Damage of a High Fat Meal?

Eating more fiber may help you lose weight, but not by canceling out the calories you've already eaten. Nutrition Diva explains how eating more fiber can (and can't) help you manage your weight and which foods to choose. 

Monica Reinagel, MS, LD/N, CNS
4-minute read
Episode #510
Foods rich in fiber

Perhaps you saw the headlines last week about a new analysis finding that people who consumed a lot of fiber are significantly less likely to die from heart disease, stroke, Type 2 diabetes, and colon cancer.

How could such a frumpy nutrient make such a big difference in our health? After all, fiber is, by definition, indigestible by humans. It provides no vitamins, minerals, or energy. And yet, fiber intake is consistently linked with lower disease risk.

There are a number of possible explanations.

How Fiber Keeps Us Healthier

First, fiber has the charming habit of taking out the trash. Insoluble fiber acts as a sort of broom, sweeping waste material out of the large intestine and lowering the risk of colon cancer. Soluble fiber acts more like a sponge, sopping up cholesterol, thereby lowering the risk of heart disease.

See also: What is the Difference Between Soluble and Insoluble Fiber?

Secondly, although fiber is not digestible by humans, it does provide lot of good nutrition for the beneficial bacteria that live in our intestines. Diets that are higher in fiber tend to give rise to a more robust and varied population of intestinal bacteria. These little beasties, we are learning, influence our health in a wide variety of waysaffecting everything from appetite, to immune function, to metabolism, and even our mood.

Thirdly, foods that are high in fiber are often high in other nutrients as well, such as anti-oxidants, phytosterols, lignans, and minerals. If your diet is high in fiber and you're getting most of that fiber from whole foods, chances are that your diet is high in a variety of disease-fighting nutrients. 

And finally, your risk of heart disease, stroke, Type 2 diabetes, colon cancer, and many other diseases is lower when you are not overweight. Fiber can play a positive role in weight loss and managementwhich could also help explain why people who eat more fiber have lower disease risk. But the role of fiber in weight loss is often misunderstood.

Take for example this email I recently received from Bill:

“If I eat a high-fat meal, I sometimes follow it immediately with a bowl of very high-fiber cereal, thinking this fiber will help compensate for the high fat intake or otherwise bad food choice I made. Does this strategy make sense? Should fiber be thought of as a way to 'discount' other food choices you make?”

Does Fiber Cancel Out Calories?

There’s an old saying that when you find yourself in a ditch, the first thing you should do is stop digging. Similarly, if you are in a situation where you’ve overeaten, eating more is rarely your best move.

Eating fiber (or taking fiber supplements) won’t cancel out calories you’ve already eaten. If you chase a high-calorie or high-fat meal with a bowl of high-fiber cereal, you’re just adding yet more calories to what you’ve already taken in, and increasing the load on your digestive system.

Meals that are higher in fiber may cause a more moderate rise in blood sugar than meals that are low in fiber. But adding the fiber after the fact is probably not a terribly effective strategy. If you’ve overeaten (or even if you haven’t), a better plan for reducing the impact of a meal on your blood sugar would be to head out for a walk.

See also: What to Do When You've Eaten Too Much Sugar

Even though fiber can't undo the damage from overeating, it can still be helpful in managing your weight. Here’s how:


About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show. 

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