Patients who ate a meal in 30 minutes had higher levels of two peptides that signal satiety -- peptide YY (PYY) and glucagon-like peptide (GLP-1) -- than those who wolfed down their food in five minutes, according to Alexander Kokkinos, MD, PhD, of Laiko General Hospital in Athens, Greece, and colleagues.
"Most of us have heard that eating fast can lead to food overconsumption and obesity, and, in fact, some observational studies have supported this notion," Kokkinos said. "Our study provides a possible explanation for the relationship between speed eating and overeating by showing that the rate at which someone eats may impact the release of gut hormones that signal the brain to stop eating." Anecdotal evidence has shown that eating quickly may not induce satiety the way eating more slowly does.
Recently, knowledge of the mechanisms involved in appetite control has increased. PYY and GLP-1 (which make patients feel full) and ghrelin (which makes them feel hungry) have been shown to act on the hypothalmus in regulating energy intake.
But postprandial concentrations of appetite-regulating hormones had not yet been examined in the context of different rates of eating, the researchers said.
So they conducted a crossover study of 17 healthy adult male patients, who each ate 300 mL -- or 675 calories worth -- of ice cream in two different scenarios: in one session they ate the ice cream in five minutes, in the other, 30 minutes.
The researchers took blood samples at the beginning of the study and at 30-minute intervals until the end of the session, 210 minutes later, to measure levels of ghrelin, PYY, and GLP-1.
Patients also assessed their hunger and fullness via questionnaire at those time intervals.
The researchers found that levels of PYY were higher after the 30-minute meal than after the five-minute meal over the course of the study (5,250 versus 4,133 pmol/L/min, respectively, P=0.004).The same was true for levels of GLP-1 (8,794 versus 6,219 pmol/L/min, respectively, P=0.001). There were no differences in hunger-producing ghrelin responses, although there was a trend for lower levels of the hormone after 120 minutes for the 30-minute meal group.
"This suggests that rate of eating may not influence this orexigenic gut hormone as much as the anorexigenic peptides," the researchers said.
More patients said they felt full immediately after the end of the 30-minute meal compared with the five-minute meal, but these results were not significant.
The investigators noted that the subjective scales they used may not have been sensitive enough to discern differences in fullness. Patients reported no differences in hunger scores between meal groups. Also, results were the same in both normal-weight and overweight patients, the researchers said.
"Eating at a physiologically moderate pace leads to a more pronounced anorexigenic gut peptide response than eating very fast," the researchers said. "The warning we were given as children that 'wolfing down your food will make you fat' may, in fact, have a physiological explanation.'"
Explain that eating quickly may curb the response of hormones that signal satiety, potentially leading to overeating.
Note that patients who ate a meal in 30 minutes had higher levels of two peptides that signal satiety -- peptide YY (PYY) and glucagon-like peptide (GLP-1) -- than those who wolfed down their food in five minutes, but levels of ghrelin -- which signals hunger -- were not different.
Journal of Clinical Endocrinology & Metabolism, online:
Kokkinos A, et al "Eating slowly increases the postprandial response of the anorexigenic gut hormones, Peptide YY and Glucagon-like peptide-1" J Clin Endocrinol Metab 2009; DOI: 10.1210/jc.2009-1018.