Eating Fast Is Associated With Being Overweight 

By Stathis

It seems obvious that what we eat is associated with how much we weigh, but scientific research is now suggesting that how we eat may also play a role in determining our likelihood of being overweight. Specifically, eating quickly is now known to have an association with being overweight. Three interesting research studies conducted in recent years have looked at different aspects of this association, and taken together provide a comprehensive look at the effects of eating rate on weight. 

The earliest of the three studies, published in the 2002 edition of the British Medical Journal, demonstrated that two behaviors—eating quickly and eating until full—have a significant association with being overweight. The study, conducted by Maruyama et al. of Japan, surveyed 4140 adults and analyzed the self-reported data they provided. The researchers found that the participants who were fast eaters also had the highest values for weight, body mass index, and total energy intake. The results showed that eating quickly increased the participants' odds of being overweight, and suggested that the combination of fast eating and eating until full may have a significant effect on weight. 

Eating Rate Determines Energy Intake 

A 2008 study by Andrade et al. and published in the Journal of the American Dietetic Association expanded on the 2002 study by looking at the relationship between eating rate, the development of satiation, and total energy intake. The study consisted of 30 healthy women recruited from the University of Rhode Island and compared two eating conditions, a slow condition and a fast condition. In both conditions, participants were provided with lunch and water and instructed to eat until they were satiated (felt comfortably full). In the slow condition, the women were given a small teaspoon and told to eat small bites, chewing each 20 to 30 times and putting the spoon down in between each bite. In the fast condition, the women were given a large soup spoon and instructed to eat as quickly as was comfortable, taking no pauses between bites. 

A comparison of the two conditions showed that women eating in the slow condition ate less food than in the quick condition, both in terms of total energy intake and weight of food eaten. They drank more water during the meal and reported finding the slow condition more pleasant than the quick condition. Those in the slow condition also expressed higher levels of satiety and less hunger after the meal, even though they ate less than in the quick condition.  

Why Is Eating Fast A Risk For Overweight?   

The researchers offer several explanations for the study's results. One possibility is that stretching a meal out over a longer time period allows time for the body to signal that it is satiated before too many calories have been consumed. This is in line with the hypothesis that physiological feedback indicating satiety takes at least 20 minutes after ingesting food, which the study results suggest is true regardless of the amount of food ingested.  

Another possible explanation is that the instructions given to the women in the slow condition resulted in less intake and greater feelings of satiety. For example, the women were instructed to chew each bite many times, and the act of chewing can stimulate the body to signal it is full. It is also possible that the increased water intake in the slow condition led to feeling fuller. Finally, the researchers suggest that the increased pleasure received in the slow eating condition may indicate that eating at a leisurely pace and savoring one's food may result in greater feelings of satisfaction from a smaller amount of food. 

Eating Fast Increases Appetite-Stimulating Hormones 

Most recently, researchers took a look at the relationship between eating rate and the hormonal changes known to follow consumption of food and influence appetite. Conducted by Kokkinos et al. and published in a 2010 issue of the Journal of Clinical Endocrinology and Metabolism, the study tested the hypothesis that eating slow would be associated with increased satiety, higher levels of appetite-suppressing (anorexigenic) hormones, and lower levels of appetite-stimulating (orexigenic) hormones. The hormones measured were the anorexigenic peptides peptide YY (PYY) and glucagon-like peptide (GLP-1) and the orexigenic peptide ghrelin, all of which play roles in the regulation of appetite by acting on the hypothalamus. 

To test hormonal changes under different eating rates, researchers had 17 male volunteers consume 300 ml of ice cream under two different conditions. In the quick-eating condition, participants ate the ice cream in two equal portions 5 minutes apart. In the slow-eating condition, the participants ate the ice cream in 7 equal portions, each 5 minutes apart (a total of 30 minutes). All participants had blood samples taken before they ate the ice cream and at 30-minute intervals over the next 210 minutes.

Analysis of the blood samples showed that levels of PYY and GLP-1, the anorexigenic peptides, were higher after the 30-minute meal, suggesting that eating at a moderate pace results in a stronger appetite-suppressing hormonal response. When measured 2 hours after the meal, ghrelin levels were lower in the 30-minute condition, although there was no significant difference in ghrelin levels between conditions.  

Conclusion - As illustrated in the 2002 study, eating fast is clearly associated with being overweight, and subsequent studies have provided some insight into the reasons for this relationship. Taking the results of all three studies into consideration suggests that slowing your eating speed will result in feeling fuller and less hungry while consuming fewer calories, possibly due to the effects of eating speed on the body's production of hormones that control appetite. Following the simple suggestions in the 2008 study—take smaller bites, chew thoroughly, and put your utensils down between bites—can help you eat more slowly, savor your food, and actually eat less while enjoying your meal more.

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