Speedy eaters likely to be heavier

The study doesn't prove that speed-eating will necessarily cause women to pack on extra pounds, but researchers believe it might influence how much food people ingest.

"It's possible that with rapid eating, there are ample calories being eaten" before feeling full, said Kathleen Melanson, a professor at the University of Rhode Island in Kingston who was not involved in this study.

Researchers mailed a survey to about 1,600 New Zealand women aged 40 to 50 years, asking them to rate themselves on how quickly they ate and also to provide their height, weight and other lifestyle and health factors.

About half of the women described themselves as middle-of-the-road in terms of their speed of eating. Thirty two percent fell in the fast or very fast categories, and about 15 percent of women considered themselves slow or very slow eaters.

The women at the slowest end of the scale had the lowest body mass index (BMI), which is a measurement of a person's weight relative to their height.

For each step up the speed scale, the BMI rose by 2.8 percent. That translates to nearly six pounds for an average U.S. woman.

Caroline Horwath, the senior author of the study and a professor at the University of Otago, said she expected to see faster eaters have higher BMIs, because previous studies from Japan showed a similar relationship.

"However, we had been surprised at the strength of the association -- we hadn't expected the effect to be as large," Horwath told Reuters Health in an email.

"The size of the relationship suggests that, if the relationship is found to be causal, reduction in eating speed may be a very promising way to prevent weight gain, and may also lead to meaningful reductions in BMI in weight management programs," Horwath added.

Faster Self-Reported Speed of Eating Is Related to Higher Body Mass Index in a Nationwide Survey of Middle-Aged Women

Abstract

This study is the first nationwide population survey to explore the association between speed of eating and degree of obesity. The objective was to cross-sectionally examine the relationship between self-reported speed of eating and body mass index (BMI; calculated as kg/m²) in a nationally representative sample of New Zealand women. In May 2009, a sample of 2,500 New Zealand women aged 40 to 50 years was randomly selected from the nationwide electoral rolls. A 66% participation rate was achieved. Potential participants were mailed a self-administered questionnaire containing questions on self-reported speed of eating, demographics, health conditions, menopause status, physical activity, height, and weight. Univariate models were used to examine the associations between demographic, health and behavioral variables, and BMI, while a multivariate model was developed to investigate the relationship between self-reported speed of eating and BMI. After adjusting for age, smoking status, menopause status, thyroid condition, ethnicity, socioeconomic status, and physical activity, BMI statistically significantly increased by 2.8% (95% confidence interval: 1.5% to 4.1%; P<0.001) for each category increase in self-reported speed of eating. Although the direction of causality requires confirmation in longitudinal and randomized intervention studies, the results suggest that faster eating is associated with higher BMI in middle-aged women.

Horwath pointed out that previous studies that used slower eating as a weight loss tool haven't always had success. A recent study in China, however, found that having people chew their food more times led them to eat fewer calories (see Reuters Health story of July 29, 2011).

One of the weaknesses of the study is that Horwath's team didn't meet any of the women in the study, but relied on the women's own assessments of how quickly they ate.

Melanson said her group is working to determine whether this type of survey is a good measurement of people's true speed of eating.

She added that trying to change people's eating speed might be difficult, because "it's so habitual and ingrained in individuals. We need a lot more work to understand the roots of the behavior and, if it can be changed, how."