Trying to stay healthy can seem like a full-time job sometimes, especially with all the conflicting

information that's out there.

But I'm here to make that job a little easier.

Welcome to the Nutrition Facts podcast.

I'm your host, Dr. Michael Greger.

Did you know that a single dietary change can increase our resting metabolic rate?

Here's our story with Nutrition Facts Senior Research Scientist Dr. Christine Dennis.

We now know why fiber-rich foods can have such a powerful effect on our weight.

The evidence for the role of fiber and weight control started with so-called ecological studies.

These involve comparing population averages.

And researchers noted that populations with extraordinary fiber intakes tend to have negligible

obesity rates. For example, the average Pima Indian in Mexico, eating their traditional high-fiber

diet centered around the three sisters, corn, beans, and squash is normal weight. But the average Pima on

U.S. reservations has obesity. The problem with dealing with population averages is that we don't know

if the individuals eating the higher fiber diets are themselves necessarily the ones protected from

obesity. What do we see in cohort studies where individuals in their diets are

followed over time? A cohort study of overweight youth found that the amount of fiber found in a

single half cup daily serving of beans, about six grams, over about a two-year period, was associated

with a profound 25% difference in abdominal obesity.

In about the same time frame in middle-aged women, each 2-gram increase in daily fiber was associated with a weight decrease of about a pound.

The postpartum period seems to be a critical time for women to be at risk of retaining the

weight put on during pregnancy. A study of

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