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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. "We have to keep in mind that weight loss and weight loss maintenance are hard," Muth said.

While the bite counter will not help people choose healthier food, it does give feedback in real time as they are eating, Muth said.

"You can then make an informed decision of whether or not to keep putting food in your mouth or to push the plate away and stop eating before you have overeaten," he 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.

The first study looked at whether people changed how much they ate when getting bite-count feedback from the wrist-worn device. In this study, participants were further split into groups depending on the size of the plates they were eating from.

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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.

People instructed to take 12 bites did take significantly fewer bites than the higher goal group. But people who had the 12-bite goal took larger bites, so the calorie intake of both groups was roughly the same, the researchers reported June 23 in the Journal of the Academy of Nutrition and Dietetics.

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.

Collins recommended another health tracking method: "Self-monitoring of the food you eat using a diary on your phone, computer/iPad or even paper is another way to help you become more aware of what you eat and drink," she said by email.

She said that when people don't want to keep a food diary, becoming more aware of "how" they eat by using smaller plates and monitoring bites may be helpful.

"Weight loss and weight gain do not happen in a single bite or even a single meal," Muth advised. "The key is to change your behavior slowly over time in a way that your body and mind can adjust to these changes."

While most dieters want fast change, the necessary steps can be difficult to sustain. "Make small changes every day, continuously self-monitoring your behavior, and long-term success will be more achievable," Muth said.