Biting less than you can chew

“Don’t put so much in your mouth” is the advice parents give at the dinner table, especially to teenagers just arrived home after sports training. I used to eat at the same table as a motorbike fanatic at boarding college in Adelaide. We used to call him “hoovermouth” as he would fill his mouth until he had cheeks like a trumpet player. He would also eat with oily hands because his theory was that bacteria couldn’t live in oil.

It appears that how much you stick in your mouth could influence how much you keep sticking in your mouth. One weight loss tip has always been to take small bites, chew your food and put your knife and fork down between mouthfuls (assuming you haven’t got your mitts around a burger or dipping your fingers into a bucket of popcorn).

Custard experiment

Now Dutch researchers have added a touch of credibility to that advice. Twenty two healthy, young people, without eating disorders or strange boarding house table habits were selected for the experiment. And they had to like chocolate custard too.

The custard was provided in controlled amounts – small bite size, large bite size and bite size of choice – while also being in the mouth for set amounts of time – three seconds, nine seconds or a time they preferred. The time in the mouth was termed the Oral Processing Time, or OPT, as scientists love acronyms. Every thing was automated. Little beeps would signal when to bite and when to swallow. They were told to stop eating when they felt comfortably full.

Less food, more time

The least total amount of custard was eaten when the bite size was the smallest and the OPT was the longest. Compared to eating the custard ad libitum, they ate 32% less food before feeling full. Once either the bite size was increased or the OPT was shortened, more total food was consumed.

Although the eating situation was highly controlled and therefore not natural, the results were supportive of previous similar research. One earlier study even had people wear a dental prosthetic to reduce the oral cavity in the mouth and found they ate 25% less food. Why hasn’t someone put those on the market yet?

What does it all mean?

It makes sense that if we take longer to eat our meal, the hormones that trigger the appetite centre are going to kick in before we overeat. It also makes sense that we should take a little longer to enjoy the flavour and texture of food (aka chewing).

The advice to bite off smaller amounts and enjoy them over a longer time has always been good advice it seems. There lies one of the problems we have with many take-away foods – their flavour hits the palate quickly in the form of fat, sugar and salt and they are usually soft and quick to eat, chewing hardly required.

Reference: American Journal of Clinical Nutrition 2009; 90: 269-275