People eat more when they are glued to the television, and the more entertaining the programme, the more they eat, according to new research.

It seems that distracted brains do not notice what the mouth is doing, said Dr Alan Hirsch, neurological director of the Smell and Taste Treatment and Research Foundation in Chicago.

Hirsch explored the impact of smell, taste and eating behaviors while watching TV by measuring potato chip consumption.

Forty-five volunteers ate as many chips as they wanted during five-minute intervals while they watched monologues by late-night talk show hosts David Letterman and Jay Leno.

They also were given chips to eat when the television was off.

Hirsch found people ate an average of 44 per cent more chips while watching Letterman and 42 per cent more while viewing Leno, than when they did not watch TV.

"If you can concentrate on how the food tastes you'll eat less because you'll feel full faster," Hirsch said in an interview at the Endocrine Society's annual meeting in Toronto.

"So if that's the case, let's look at the opposite. What if you're distracted? If you're distracted, in theory, then you'd eat more."

Through his research at the foundation, Hirsch has helped people overcome the loss of sense and taste sensation, which typically results in weight gain because the brain does not know when it should stop eating.

The ventromedial nucleus in the hypothalamus, where the so-called satiety centre is located, tells the body whether it is hungry or full. If it is inhibited or tricked, the result can be changes in eating patterns, he said.

"People who cook spaghetti all day don't fell like eating spaghetti at the end of the day," said Hirsch. "By being exposed to a smell all day long it's tricking the hypothalamus."

Volunteers were asked to concentrate on the sensory characteristics of the food such as taste and smell. Researchers say these sensory clues, in addition to internal body changes, signal satiety.

But when distracted, a person does not pay attention to either the body's sensations of feeling full, or to the sensory characteristics of the food.

Many studies have linked obesity to watching television and that link is likely due to inactivity, Hirsch said. But perhaps entertaining shows are also contributing.

"If you want to lose weight, turn off the television or watch something boring," he said.

 [编辑：职绚]