By Kathleen Couillard – Agence Science-Presse
Books devoted to dieting and general health have long recommended that we eat slowly during a meal. But has science demonstrated this to work? The Rumor Detector is on the case.
Taking your time when eating is recommended by the Canada Food Guide. We read that this has several advantages: you avoid eating too much, you make healthier food choices, you take time to savor your food…
Nutritionist Geneviève O’Gleman vaunts this approach too, on her Nutritionniste urbain web site. “The taste buds need time to appreciate what we eat. In eating slower, we more easily recognize the sensation of satiety (feeling full),” she writes.
Measurable Health Effects
In 2018, Japanese researchers published the results of a vast study conducted on 59,717 persons suffering from type 2 diabetes. Participants were followed for six years. Researchers noted that eating slower reduced body mass and cut obesity risks.
Effects can vary according to the characteristics of those being studied, concluded one Spanish study on elderly subjects with a high risk of cardiovascular ailments.
But overall, research has tended to confirm the benefits of eating slowly, as seen in a meta-analysis of 23 studies conducted before 2014. People who ate fast had a higher body fat content and were more prone to obesity. The analysis also concluded that different studies aren’t always comparable, possibly because the definition of “eating quickly” isn’t always the same.
Elsewhere, other research carried out in the past few years indicates that eating rapidly can increase the quantity of abdominal fat and the blood levels of certain fats, like triglycerides. As well, eating fast is associated with a resistance to insulin. One Japanese study shows that people who eat their meal in 10 minutes rather than in 20 minutes have higher concentrations of blood sugars. In other words, eating quickly can increase your risk of type 2 diabetes.
Eat Slowly = Eat Less
What about the amount of food you eat? According to the Japanese study published in 2018, people who eat fast continue to eat even after they have consumed enough calories. British researchers noted in 2018 that those who eat slowly feel full before they might eat too much.
Other Japanese researchers noted in 2015 that people who eat fast chew less. This can have an effect on how full someone feels, they found. And British researchers think that eating slowly may delay the speed at which food leaves the stomach.
No matter what the mechanism, the meta-analysis concludes that eating slowly diminishes the quantity of calories consumed. This effect persists for a while after the meal: people who eat slowly have less of an appetite to eat an hour after their meal, according to Texas scientists. Moreover, the British experts saw that those who ate their food slower consumed 25% less food when offered a snack three hours later.
Hormonal Effects?
According to many scientists, eating a lot of calories in a short time, as well as the frequency of chewing, may have an effect on the production of hormones that control appetite and the feeling of being full. Among these hormones is ghrelin; the peptide tyrosine-tyrosine (PYY); and the glucagon-like peptide-1 (GLP-1).
Nonetheless, the studies on hormones and fast eating offer contradictory results. For example, a team of British and Swedish researchers, as well as from the University of Bristol and Greece, all showed that eating slowly modified the body’s production of ghrelin, PYY and GLP-1. However, the Texas researchers found no such causal link.
Verdict
The data converges to affirm that eating slowly is good for your health. But the mechanisms controlling this phenomenon are not yet well understood.
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