We can all think of times when we have gobbled down food without even really tasting it.
But could that kind of high speed eating contribute to weight gain?
This is the question being posed by researchers working in Europe's most advanced 'flab lab', a unit that does hi-tech research into obesity.
Its official name is a whole body calorimeter and scientists at the University Hospital Coventry and the University of Warwick are hoping it will help them have a better understanding of how food, exercise, medicines and sleep affect our weight.
One of their first experiments is into the speed of eating, the way it changes appetite, and the rate at which energy is burned up.
Helga Perry is one of about a dozen patients taking part. She will spend three separate days in the lab, which is an air-locked chamber that makes very precise calculations of how much energy she burns.
On day one of the experiment, she will eat lunch in 10 minutes, on the second day she will be told to take 20 minutes, and on a third, she will have a 40-minute meal. The researchers control this by dividing her sandwich and yoghurt into small portions and giving them to her at five-minute intervals.
At the end of the day her appetite levels are tested when she is offered an all-you-can-eat selection of food.Helga Perry has her lunch delivered to the lab in small portions
Provisional research from Japan suggests that eating more slowly may help suppress the appetite and lower the risk of developing diabetes.
The researchers at University Hospital Coventry say they want to see whether they reach the same conclusion in this more carefully controlled trial.
Lead researcher Dr Tom Barber says the experiment could add to scientific knowledge about obesity: "If you prolong your meal this could, over time, actually promote weight loss."
Almost one in four of all adults in the UK are currently obese and by 2050 that is expected to rise to one in two.
Helga Perry says she is taking part in the trial because she thinks it is important to help increase the understanding of obesity.
"If it does something to help people who've struggled to lose weight, like me, then it can only be a good thing," she said.Prof Sudhesh Kumar. who runs the unit, also hopes to investigate links between obesity and diabetes.
Prof Sudhesh Kumar runs the flab lab - the Human Metabolic Research Unit. He said: "The research potential of this new unit is vast, we are looking forward to being able to make a difference to patients around the world."
At the end of her second day of taking part in the trial, Helga Perry emerges from the sealed unit with a sigh of relief and takes a deep breath of fresh air.
She spent her day reading and browsing the web, so she hasn't been bored, but she did find it confining. "It was like being in a submarine," she observes.
She says she found it interesting to be forced to eat so slowly: "I usually gobble my food down, it felt as if I tasted my lunch properly."
She ate a small portion of food at the end of the day, but did not feel very hungry.
The researchers do not expect results for a few months, but ultimately they hope to offer some answers to the many questions about the causes of the world's obesity epidemic.