Cutting out after-dinner snacks and avoiding late meals are also linked to people shedding the pounds, researchers found. During those appointments, people were asked about their eating and sleeping habits, including how fast they typically ate and whether they regularly skipped breakfast, snacked after dinner or ate before bed.
The claims data included information on the dates of consultations and treatments, while the check-ups included measurements of weight and waist circumference, and the results of tests for blood chemistry, urine, and liver function.
Statistical analysis revealed that 21.5 percent of people who described themselves as slow eaters were obese compared with almost 30 percent of normal-speed eaters and 45 percent of fast eaters.
Around half of the total sample (just under 52%) changed their eating speed over the course of the six years.
Also, the terms "fast", "normal" and "slow" were used by the participants of this study just as a self-evaluation, without a strict definition of the eating speeds, and without timing the participants while eating.
A recent study published in The Lancet medical journal reported that nearly a third of Irish children are now overweight and the country ranks 58th out of 200 countries for its proportion of overweight youths.
The research team also found that people who brought minor tweaks to their lifestyles like saying no to post-dinner snacks, eating slowly, and leaving a few-hour window between dinner and bedtime reduced their BMI. But even after controlling for other potentially influencing factors, the researchers found that eating speed appeared to be an independent factor in weight and body mass index measures.
"Interventions aimed at altering eating habits, such as education initiatives and programmes to reduce eating speed, may be useful in preventing obesity and reducing the risk of non-communicable diseases", the authors conclude.
The study looked specifically at people in Japan with type 2 diabetes who had one to three health check-ups between 2008 and 2013. The fast-eating group had also larger waistlines on average than their peers in the other two groups. In addition, the researchers did not track how much the participants ate or whether they engaged in physical activity.
One of those habits was eating speed, ranked on a scale of slow, medium to fast. More calories result in weight gain. Commenting on the research, Simon Cork of Imperial College London said it "confirms what we already believe, that eating slowly is associated with less weight gain than eating quickly".
"In contrast, eating slowly may help to increase feelings of satiety before an excessive amount of food is ingested". It takes fast eaters longer to feel full simply because they don't allow time for the gut hormones to tell the brain to stop eating. Next time you consider a weight loss program make sure your brain doesn't hold you back.