Whole Grains and Belly Fat

For the last few weeks we've been writing about the effects of the Mediterranean Diet in general and some of the specific components of the Mediterranean Diet on abdominal fat deposition (read: belly fat). Our patients are often concerned about belly fat, not because of its effects on their health, but because they don't like the way it looks. The truth is that abdominal fat is a good indicator of greater risks to your health.

This is why Waist to Hip Ratio is becoming the more favored method of estimating body fat, better than Body Mass Index. Body Mass Index only looks at weight in relation to height, which is a good indicator of overweight and obesity for most people, but it is limited by being unreliable for children, the elderly, people under 5 feet tall, and those who are very muscular. Waist to Hip Ratio, on the other hand, tells us physicians far more about where your body fat is deposited, which we are finding is far more of an indicator of increased health risks and is relevant for everyone.

There are two general types of abdominal fat: Visceral Abdominal Tissue (VAT), which is the fat that collects around the internal organs, and Subcutaneous Adipose Tissue (SAT), which is the fat that collects under the skin. While higher levels of both types of abdominal fat are indicators of associated health risks such as diabetes, emerging research is indicating that Visceral Adipose Tissue is more of a health concern than Subcutaneous Adipose Tissue.

Last week we wrote about the Mediterranean Diet's effects on where abdominal fat is deposited: VAT or SAT. This week we're looking at a study on one element of the Mediterranean Diet: whole grains.

Using data collected in connection with the Framingham Heart Study, a long-term, large scale study of heart health among three generations of participants, researchers with funding from the USDA and General Mills looked at the relationship between whole grain consumption and the location of abdominal fat (Am J Clin Nutr 2010;92(5):1165-71). As part of the larger study, 2,834 men and women underwent CAT scans which allowed the researchers to determine the amount and location of their abdominal fat. The study also included waist and hip measurements, height and weight, collection of demographic information such as exercise and smoking status, and included a detailed food-frequency questionnaire which included multiple types of whole-grain foods and refined-grain foods.

The researchers grouped the participants into five increasing levels of whole grain intake as well as five increasing levels of refined grain intake. The amount and location of their abdominal fat was then correlated with both their whole grain and refined grain intake.

They found that generally speaking, the more whole grains a person ate, the smaller their waist was. Further, the highest level of whole grain intake meant the lowest levels of both Visceral Abdominal Tissue and Subcutaneous Abdominal Tissue. When the researchers looked at those who had the highest whole grain intake and also factored in the amount of refined grains that group ate, they found that even those with the highest whole grain intake had more Visceral Abdominal Tissue when they ate more refined grains, compared to those who ate the least.

What this means for you

In short, it appears that eating more whole grains does not necessarily offset the effect of also eating more refined grains. The report includes a list of the most commonly eaten whole grain foods among the participants, and you can take this as a simple guide to easy whole grain choices: dark bread, whole grain ready-to-eat breakfast cereals, oatmeal, popcorn, and brown rice. These are really easy changes to make in your diet, and you'll be healthier around the waist.

First posted: May 18, 2011