To lose weight, experts suggest a focus on fiber


If you’re trying to lose weight, you could count your calories, keep track of precisely how much salt and sugar your eat, and make sure you hit certain targets for protein, carbohydrates, cholesterol and the various types of fat. Or you could set all of that aside and concentrate on just one thing: Eating at least 30 grams of fiber each day.

In a yearlong clinical trial involving 240 obese people who had metabolic syndrome, those who focused on fiber lost almost as much weight as those who followed the American Heart Assn.’s extremely detailed dietary recommendations. The average difference between the two groups — a mere 1.4 pounds — was too small to be considered statistically significant, according to a study published Tuesday in the Annals of Internal Medicine.

The researchers who conducted the trial were quick to say that the American Heart Assn. diet is certainly effective. But it’s not necessarily user-friendly.


The AHA advises dieters to:

* Eat at least 30 grams of high-fiber foods each day.

* Eat fish twice a week.

* Get protein from vegetables and lean meats.

* Get 50% to 55% of calories from carbohydrates, 15% to 20% of calories from protein, and 30% to 35% of calories from fat (including just 7% of calories from saturated fat and less than 1% from trans fats).

* Eat less than 300 milligrams of cholesterol per day.

* Minimize sugar, sodium and sugar-sweetened beverages.

* Drink no more than a moderate amount of alcohol.

If your head is spinning, you’re not alone. “The various AHA dietary recommendations may create adherence challenges,” as the study authors so politely put it.

They wondered what would happen if they emphasized the first item on that list and let the rest of them go. They had reason to think it might work: A 2012 study in Archives of Internal Medicine found that people who were advised to cut back on sitting and step up their consumption of fruits and vegetables improved their diet and exercise habits more than people who got specific instructions about increasing their physical activity and cutting back on saturated fats.

The researchers recruited 240 volunteers between the ages of 21 and 70 who met the criteria for metabolic syndrome, a condition that puts people at risk for various cardiovascular problems. All of them had a body mass index between 30 and 40, which qualified them as obese. These volunteers were randomly assigned to follow the AHA diet or to eat at least 30 grams of fiber a day. None was given any advice about physical activity.

Most people were able to stick with their assigned plan for the full year — 10% of people in the fiber group dropped out of the study, along with 13% of those in the AHA diet group.

All of those who stuck with the study lost at least a few pounds. At the end of the year, volunteers who followed the AHA diet were 6 pounds lighter, on average, while those in the fiber group had lost an average of 4.6 pounds.


The AHA dieters saw a 0.4-inch reduction in waist circumference, on average. Those in the fiber group wound up with an extra 0.1 inches around their middles, on average.

Members of both groups had lower blood pressure, lower total cholesterol and lower triglycerides. Both groups also reduced daily calories, with the AHA dieters recording a larger average decline (465 fewer calories per day) than their counterparts in the fiber group (200 fewer calories per day).

However, those in the fiber group did a better job of adding fiber to their diets. Their daily intake rose by 4.7 grams (to a total of 23.5 grams), compared with a 1.3-gram increase for those in the AHA group (to a total of 20.8 grams). On average, Americans eat just 16 grams of fiber a day.

For the most part, study volunteers who were taking medicines to control their cholesterol and blood pressure did not improve enough to stop.

“No clear between-group differences were found,” the study authors concluded.

The researchers were heartened to see that the people told to focus on fiber adopted other healthful eating habits too, such as substituting white meat for red meat.

“The challenge is to identify the ideal amount of information to change behavior without overwhelming the participant,” they wrote.


The study was funded by the National Heart, Lung and Blood Institute.

Feeling inspired to eat more fiber? The Mayo Clinic has a list of fiber-rich foods, as does the U.S. National Library of Medicine.

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