Turning the lights out or wearing a blindfold while eating could be a quick way to lose weight, according to scientists. The simple trick works because it stops diners eating for pleasure rather than for calories. It also triggers(引发)a part of the brain that is worried that unseen food may go bad.

An experiment by the University of Konstanz, in Germany, found that people who were blindfolded consumed nine percent fewer calories before they felt full, compared to those who could see. They also vastly overestimated how much they had eaten because they could not see how much was left on the plate. Blindfolded volunteers estimated they had eaten 88 percent more than they actually had.

Scientists believe that not seeing food on the table also allows the body to know when it is full in real time rather than remembering past experiences where it might have taken a full plate to feel full.

In the experiment, 50 people were blindfolded and 40 were allowed to see their food. All were told not to eat within two hours of the experiment. They were then given three 95g bowls of chocolate ice-cream and invited to eat for 15 minutes. Their bowls were taken away and the remaining ice-cream weighed, while the participants were quizzed on how much they thought they had eaten.

On average the group who could see ate 116g while the blindfolded groups ate 105g.However,the blindfolded group believed they had eaten 197g while compared with 159g for the non-blind volunteers. They were also asked how pleasant the ice-cream tasted and the blindfolded group rated lower than those who could see.

“The experienced pleasure of eating was significantly lower in the blindfolded group. Not seeing the food might have decreased the appetite.Sight plays an important role in the eating experience and in the overall dining experience.”

Previous studies have shown that the visual influence of food plays a large part in the taste. While restaurants that allow diners to eat in the dark state that it triggers other senses,in fact eating in darkness is likely to taste far milder than usual.

Many people turn to doctors or self-help books, but they ignore (忽视) a powerful thing that could help them fight illnesses: their friends.

Researchers are now starting to pay attention to the importance of friendship in health. A 10-year Australian study found that older people with a large circle of fiends were 22 percent less likely to die during the study period than those with fewer friends. Another study showed that there was an increase of nearly 60 percent in the risk (危险) for obesity among people whose friends gained weight. And last year, Harvard researchers reported that strong social relationship could improve brain health as we age.

“In general, the role of friendship in our lives isn’t well realized,” said Rebecca, a professor at the University of North Carolina. “Friendship has a bigger effect on our psychological (心理的) health than family relationships.”

While many friendship studies are about the close relationships of women, some research shows that it can do good to men, too. In a six-year study of 736 middle-aged men, having friendships reduces the risk of heart attack. Only smoking was as important a risk factor (因素) as having little social support.

The exact reason why friendship has such a big effect isn’t entirely clear. While friends can send a sick person to the hospital or pick up medicine, the advantages go well beyond physical help. Friendship clearly has a big psychological effect. “People with stronger friendships feel like there is someone they can turn to,” said Karen, a doctor. “The message of these studies is that friends make your life better.”

For an old person, his brain may perform not so well as before. But a new study suggests that some parts of brain may already decline in young adulthood.

The study, which followed more than 2,000 healthy adults between the ages of 18 and 60, found that certain mental functions — including measures of abstract reasoning, mental speed and puzzle-solving — started to dull as early as age 27. Meanwhile, the decline of memory generally became apparent around age 37.

On the other hand, indicators of a person’s accumulated knowledge — like performance on tests of vocabulary and general knowledge — kept improving with age, according to findings published in the journal Neurobiology of Aging.

The results do not mean that young adults need to start worrying about their memories. Most people's minds function at a high level even in their later years, according to researcher Timothy Salthouse. “According to these patterns, some kinds of flexibility in the brain decline relatively early in adulthood, but throughout adulthood the knowledge pool in one’s command and the effective combination with one’s capabilities may be on the increase without the attack of diseases.” Salthouse said in a news conference.

The study included healthy, educated adults who took standard tests of memory, reasoning and perception at first and at some point over the next seven years.

The tests are designed to detect subtle (细微的) changes in mental function, and involve solving puzzles, recalling words and details from stories, and identifying patterns in collections of letters and symbols.

In general, Salthouse and his colleagues found that certain aspects of cognition (认知能力) generally started to decline in the late 20s to 30s.The findings explain normal age-related changes in mental function, which could aid in understanding the process of dementia (痴呆), according to the researchers. “By following individuals over time,” Salthouse said, “we gain insight in cognition changes, and may possibly discover ways to slow the rate of decline.”

The researchers are currently analyzing the study participants’ health and lifestyle to see which factors might influence age-related cognitive changes.