How to counteract overweight… by eating

Eat slowly, how many times have you heard this! And it is good to listen to this advice, not only to improve digestion but also to keep body weight under control by combating obesity and overweight. This is what emerges from a very recent scientific research published in the Scientific Reports journal of the prestigious Nature group by a Japanese team (Hamada et al, Scientific Reports, 2021). But let's try to understand this fascinating topic better!

Diet-induced thermogenesis is a consequence of ingesting food. In particular, this process triggers a series of reactions that lead to an increase in blood flow to the organs responsible for digestion and intestinal motility, resulting in an increase in energy expenditure. More energy is consumed and therefore less fat and extra pounds are accumulated. Previous studies have already verified that eating slowly and chewing for a long time are associated with an increase in diet-induced thermogenesis. However, some points remained to be clarified. In particular, it was not possible to understand whether the size of the food bite ingested, rather than the duration of the chew, could influence thermogenesis. Not only that, can tasting food also play a role in increasing energy expenditure?

To answer these questions, the researchers developed a study, using food in liquid form for the tests, so as to exclude or not a possible role of the size of the bite in thermogenesis. 11 volunteers were recruited. At the beginning, the study participants were asked to take liquid food normally by swallowing it every 30 seconds. In the second test, the volunteers were asked to hold the food in their mouth for 30 seconds without swallowing, in order to savor the food. In the third test, the volunteers were asked to hold the food in their mouth for 30 seconds and chew. Diet-induced thermogenesis was evaluated before and after the three experiments. What emerged is that diet-induced thermogenesis always increases with food consumption, regardless of how it is taken. And this is an expected result, as ingested food always activates the digestive processes. But the scientists also observed something else. In particular, thermogenesis was higher in the two groups who had tasted and chewed the food for a long time. It is believed that tasting food, and therefore eating slowly, and chewing for a long time activate motility and blood supply to the digestive organs more and more efficiently, thus increasing energy needs and helping to keep body weight under control.