Last Updated: 2003-05-20 17:02:54 -0400 (Reuters Health)

By E. J. Mundell

ORLANDO (Reuters Health) - Diet-conscious couch potatoes, beware: a new study finds that eating while lying down might leave you hungry for more.

Ultrasound stomach scans and post-meal interviews suggest that people feel full sooner when seated for a meal, as opposed to reclining.

"When you are in the seated position, as opposed to lying flat, you are going to have more of your meal retained in the lower part of the stomach," explained Australian researcher Dr. Deirdre O'Donovan. "And you're going to feel, as a result of that, less hungry and more full."

O'Donovan, a researcher at the University of Adelaide, presented her team's findings here Tuesday at Digestive Disease Week, the largest annual gathering of gastroenterologists in the world.

While previous studies have examined the effect of eating posture on the movement of food from the stomach into the small intestine, O'Donovan's team says its study is the first to examine the relationship between body position and the distribution of a meal inside the stomach.

The researchers had eight healthy volunteers consume a sugary drink laced with a harmless radioactive tracer. Each volunteer drank the liquid twice -- once while sitting and once while lying flat with his or her head propped on a pillow.

With the tracer as a marker, the researchers used ultrasound and another scanning technique called scintigraphy to examine the distribution of food in the stomach, following its passage into the small intestine for an hour-and-a-half after consumption. Participants were also asked periodically how hungry or full they felt.

"Posture didn't affect the overall rate at which food left your stomach and went into the small intestine," O'Donovan said in an interview with Reuters Health.

But it did have an impact on "whether it was in the top part of your stomach -- which it was in the lying-down posture -- or in the lower part of your stomach, as it was in the sitting posture."

People who ate while sitting up tended to feel fuller, sooner. This makes sense, O'Donovan said, because that sense of fullness is increased when food collects in the lower portion of the stomach.

So breakfast in bed might not be the best idea for those hoping to slim down for the summer.

Instead, dieters "might want to have their meals while in the upright, seated posture," O'Donovan advised. "That would give them the greatest chance of feeling full immediately after their meals."


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