Researchers from Cancer Research UK's Health Behaviour Research Centre at University College London (UCL) filmed 254 twin children aged 10-12 eating a standard meal in their homes to test whether their speed of eating was related to the amount of fat they carried and whether eating rate was a heritable characteristic.
The results indicated that the children's eating rate was partly influenced by their genes, and that a faster eating rate was linked to a higher body weight in general, and with overweight twins eating the fastest, and eating more in a sitting.
Previous experiments have confirmed that faster eating is linked to eating more, but studies making the direct link between a faster eating rate and higher body weight have produced mixed findings.
Children were divided into three weight groups to compare eating rate within the normal range as well as between obese and normal groups. The groups were: obese-overweight, higher-normal weight and lower-normal weight.
The researchers found that the overweight group ate significantly more than the other two groups. The overweight group ate the fastest at 4.3 bites per minute, followed by the higher-normal weight group which ate on average 4.1 bites per minute. The lower-normal weight group ate slowest at 3.8 bites per minute.
These findings may interest health professionals who could encourage children to slow their eating speed, to play a role in reducing their risk of becoming overweight.
It is estimated that currently more than 13,000 cases of cancer in the UK could be avoided each year if everyone maintained a healthy body weight.
Research has shown that obesity increases the risk of breast cancer, bowel cancer, womb cancer, kidney cancer and food pipe cancer. Obesity has also been linked to increased risk of other cancers including gallbladder cancer, liver cancer, ovarian cancer and cancer of the pancreas, but more research is needed to confirm this.
Lead author, Professor Jane Wardle, said: "This twin study suggests that children who eat faster inherit this trait and that it is a worrying risk factor for weight gain, which could potentially be modified in childhood.
"If eating rate can be modified, and if it results in consumption of less food, then early promotion of slower eating for all children could lower the average population weight and help to control current obesity trends."
Sara Hiom, Cancer Research UK's director of health information, said: "This is interesting research that adds to our understanding of the causes of childhood obesity, an increasingly common and health threatening issue. But parents concerned about their children's weight should also consider the type of food being consumed as well as how fast their children eat it.
"Eating lots of burgers, chips and cakes more slowly will not solve the problem on its own. Children should be encouraged to eat a wide variety of vegetables and fruit while limiting the sugar, fat and salt in their diets."
An audio clip is available for download: http://media.cancerresearchuk.org/media/press/Jane_Wardle_Dec08.mp3
Clare H Llewellyn et al. Eating rate is a heritable phenotype related to weight in children. American Journal of Clinical Nutrition. Monday 8 December 2008. AJCN MS 26175.
Cancer Research UK advises that individuals help reduce their risk of getting cancer through taking regular exercises and eating a diet that is low in red and processed meat, low in fat and includes fruit and vegetables as part of a balanced diet in order to maintain a healthy body weight. People can also lower their risk by avoiding alcohol, not smoking and reducing their UV exposure.
The children were left alone with a video recorder in a room to eat from a plate of 24 sandwich quarters with their own choice of filling along with two pre-chopped fruit salads. This was more food than the children could manage because in all cases food was left over. The researchers measured total eating time and eating rates across the meal.
Each child was given a score representing their average bite size during the meal and eating rate was calculated by dividing number of bites by total of minutes spent eating.
Participants were drawn from the Twins Early Development Study (TEDS) a population-based sample of more than 15,000 twin pairs born in England and Wales between 1994 and 1996. The research only studied twins with white ethnicity.
A total of 160 families (320 children) were visited at home by researchers who filmed the twins eating a light meal. Due to technical errors video data were unavailable for 42 twins.
The films of children eating plates of sandwiches were coded by independent observers to determine eating rate and deceleration of eating as they became full.
Top ten weight loss tips based on scientific evidence
You can reduce your risk of cancer by keeping to a healthy weight. If you are overweight or obese, try and lose weight.
Cancer Research UK and Weight Concern have joined forces to develop Ten Top Tips for a healthy weight. Visit www.cancerresearchuk.org/healthyliving for more information. Anyone affected by cancer can contact Cancer Research UKâ€s cancer information nurses on 0808 800 4040 (freephone) or visit the charity's patient information website www.cancerhelp.org.uk