Overweight and obese people tend to eat more quickly than their lean counterparts. It may seem obvious that eating slowly would help people eat less, but research has not consistently shown this, largely because the studies have varied so much in design and quality. Now an analysis of 22 well-designed clinical experiments on the effect of eating rate on calorie intake, published in the American Journal of Clinical Nutrition, has confirmed this weight-control strategy.
The studies used a variety of ways to get people to slow down at the table. In some, people were simply instructed to chew more and take their time eating. In others, food consistency was manipulated—typically people were given either soft foods (to speed eating rate) or hard versions of the same foods (to slow it). Or else “food delivery” was altered to affect eating rate: eating with a spoon (slow) versus a straw (fast), for example, or eating from a slowly refilling container versus a quickly refilling one. Some studies used computers to monitor eating rate and provide feedback.
Overall, the studies found that when people ate more slowly, they consumed significantly less, on average, than when they ate faster. The more they slowed down, the fewer calories they consumed. What’s more, slower eaters apparently felt satisfied with less food, since they were no likelier than fast eaters to report being hungry at the end of the meals or a few hours afterwards. That reduces the risk that they’ll compensate by eating more later on.
Researchers have proposed several mechanisms to explain the effects of eating rate on food intake:
- Slow eating may affect satiety hormones (such as leptin) and insulin levels, as well as slow gastric emptying. In effect, it allows more time for satiety signals to reach the brain (this generally takes about 20 minutes).
- Eating more slowly increases “oral sensory exposure,” making you more aware of the taste, smell, and texture of foods. This can increase satisfaction with fewer calories.
- Taking more small-sized bites and chewing more may also signal your brain that you’re full and thus help reduce calorie intake. As the analysis suggests, “it may be that some people have developed a learned association between the number of bites, chews, or sips and feelings of satiation that bring a meal to an end.” For instance, you may need to take 40 bites or chew 400 times at a meal to feel satisfied, regardless of how much food is in each mouthful.
Bottom line: Weight control depends not only on choosing healthy, filling foods and dishing out reasonable portions, but also on the manner in which you eat them. One key concept is “mindful eating”— eating slowly, paying attention to each bite, and being aware of your surroundings— which can allow you to eat less food but enjoy it more. Get more tips on mindful eating here.