Eating Quickly: Will it Make You Fat?

Eating Quickly: Will it Make You Fat?

Eating Quickly: Will it Make You Fat?

We’ve all heard at one time or another that wolfing down food is bad form and may even make a person fat. Indeed, many children have been chastised over the years by their grandmothers on just this point. But isn’t this merely an old wives’ tale? According to new scientific studies, grandma may have been right after all.

Eating Fast Means Eating More

Research indicates that eating quickly is linked to increased calorie consumption. According to Dr Andrade’s study published in the Journal of American Dietetic Association, the speed at which a person eats does indeed affect how much food he ingests.

To test this, Andrade et al. used two groups of individuals. Each group was given a large portion of food and told to eat as much as desired. One group was given a large spoon and was instructed to eat as fast as was comfortable. The second group was given a smaller spoon and told to take small bites and to chew each bite twenty to thirty times before swallowing.

The study found that those in the slow eating group consumed significantly fewer calories and drank more water than those in the fast eating group. What’s more, those who took smaller bites and ate more slowly actually felt more full than those who ate quickly, even though they ate less food.

This study certainly seems to support grandma’s theory. Not only does eating quickly lead to the ingestion of more food, but it doesn’t even stave off hunger. It is easy to imagine that a person who eats more but is still hungry will gain more weight than someone who eats less and feels full.

Eating Quickly and Obesity

A different study, conducted by Maruyama et al. and published in the British Medical Journal, supports the thesis that eating quickly is linked to obesity. Maruyama’s study found that those who ate more quickly were significantly more likely to be overweight. In addition, the study found that those who ate until feeling full were also more likely to be overweight. It was concluded that both eating quickly and eating until full could have a greater impact on being overweight.

Hormones and Eating Speed

A study published a few years ago in the Journal of Clinical Endocrinology and Metabolism explored the possible causal effects of eating speed. The study’s author, Kokkinos, conjectured that the speed at which a person eats may affect hormone levels, which might explain the difference in satiety ratings between those who eat quickly and those who eat slowly.

To test this, Kokkinos created a slow eating group and a fast eating group. Both groups were given the same total amount of ice cream to eat. However, the fast eating group received its ice cream in two portions, which were eaten only five minutes apart. In contrast, the slow eating group received seven portions, which were eaten five minutes apart over a thirty minute period.

Throughout the experiment, blood samples were taken at regular intervals so that hormone levels could be measured. According to the study, there were significantly larger amounts of the anorexigenic peptides PYY and GLP-1 for the slow eating group. Additionally, it was found that the levels of the hormone ghrelin, which increases the feeling of hunger, were higher for the fast eating group after a period of two hours.

Kokkinos’ study is important because it gives us a physiological explanation for what happens when we eat quickly or slowly. Eating slowly apparently leads to an increase in PYY and GLP-1. These hormones interact with the hypothalamus to make a person feel full. Eating slowly also results in lower levels of ghrelin two hours after eating. Ghrelin interacts with the hypothalamus to create the feeling of hunger. This indicates that those who eat slower continue to feel full long after mealtime is over.

Good News for Dieters?

These studies offer hope for dieters. Most people who struggle with their weight eat more calories than they can burn. The straightforward solution to this problem is to either reduce the number of calories consumed or to increase the number of calories used each day.

Exercise is the best means for burning calories, and various diet plans are often used to reduce caloric intake. However, Andrade’s study offers a promising approach to reducing caloric intake: take smaller bites and eat slower. Research clearly shows that pacing your eating will reduce the number of calories you consume.

In addition, taking time to eat your meal will help you feel fuller. This is why clinically researched weight loss programs like Weight Watchers and Nutrisystem (read about them here) place a lot of emphasis on helping you eat slow.  And as demonstrated in Kokkinos’ study, eating slowly can help you to feel full even hours after your meal. The reverse is also true. If you eat quickly, you will still feel hungry right after eating, and you will likely be even hungrier a few hours later. Eating quickly leads to more and more eating with little hunger satisfaction.

So if you are struggling with your weight, pay attention to how fast you eat. You may find that simply slowing down and enjoying your meal is all it really takes to bring your weight loss plan to the next level.

Written by
Steven Vardalos, PhD, has been in the medical research field for more than a decade. He closely follows current scientific studies on nutrition, weight loss and obesity treatments, and enjoys presenting these findings in an interesting and accessible format. Steven believes that our health is our biggest asset. This is why he follows a healthy lifestyle. He eats foods that are nutrient-rich, and purchases only organic produce. He exercises daily because he practices what ancient people proclaimed: "Mens sana in corpore sano". Given his educational background in science, he likes to write on interesting science topics using layman's terms.