People who wear "bite counters" on their wrists while eating tend to cut down on how much they consume during a meal, a study suggests. Several years ago, Eric Muth and colleagues at Clemson University in South Carolina developed a way to track how much people eat based on their wrist motion.

Muth told Reuters Health by email that self-monitoring is vital when trying to meet health goals. While the bite counter will not help people choose healthier food, it does give feedback in real time as they are eating, Muth said.

Muth and his team conducted two studies, the first with 94 participants and the second with 99. In both studies, the participants were mostly women, around 19 years old, and had a body mass index of 23, which indicates that they were at the upper limit of normal weight.

The subjects ate meals together in a lab set up to mimic a restaurant setting. Some participants wore bite counters, which also gave calorie estimates as people ate, while other participants did not wear counters and acted as a comparison group.

People eating only from large plates ate around 4.5 bites more than those with small plates. This was true even when participants received bite count feedback. However, people eating from both the large and small plates and getting bite count information significantly reduced how much they ate, taking five fewer bites than people unaware of how many bites they were taking.

The second study also used large and small plates and bite counting devices, but this time participants were told to take either 12 or 22 bites.

Clare Collins, a researcher and professor of Nutrition & Dietetics at The University of Newcastle in Australia pointed out that the study participants were mostly normal weight. The results could be different if the study was done in an overweight group, she said.