3．Is carrying a few extra pounds into your senior years healthy？Advice has been mixed．Now，two studies published this month attempt to better define the ideal weight for fitness and longevity for adults over age 60．
The main point is that you don't need to worry about being slightly overweight，as long as that extra weight is maintained at a consistent level．However，being very overweight is detrimental to health，and exercising to lose body fat and to gain muscle mass is always beneficial．
Determining the ideal weight for older people has been a pursuit，with researchers looking for what weight is not too thin，but not too fat．Studies have suggested that being slightly overweight can be protective．
For example，a 2001study by researchers at Yale University found that moderately overweight senior adults with a body mass index （BMI） of 27-two points higher than the BMI of 25that defines being overweight-lived longer than seniors who were either thinner or heavier．There's a fine line here，though，because carrying extra pounds is a risk factor for many types of cancer and other diseases．And，according to the researchers behind the two new studies，the general public has misinterpreted the Yale findings to mean that being very overweight is healthy．
One new study，published this month in the American Journal of Epidemiology by researchers at The Ohio State University in Columbus，found that seniors who maintained a stable，slightly overweight status survived most probably over the 16years surveyed．Those seniors who had a so-called healthy weight going into the study （a BMI between 18.5and 25）and who gained weight，but stayed below BMI 25，had a slight possibility of surviving over the study period．
People in the obese group，with a BMI higher than 35and who continued to gain weight，faced the worst among all the groups in the study．But next-to-last were normal-weight people who lost weight，but this was likely because they became sick，the researchers said．
The second study，appearing this month in the journal Obesity，was conducted by researchers at Wake Forest Baptist Medical Center in Winston-Salem，N．C．，and supports intentional weight loss among senior adults．Whether weight loss is beneficial has been debated because of this concept that being overweight is protective．
In short，the researchers found that physical activity and weight loss for overweight and obese adults resulted in lower cardiovascular （心血管） disease risk and improved mobility．This finding supports previous studies demonstrating that exercise builds muscle and bone strength，improves balance and coordination，prevents falls and enables seniors to enjoy a more active lifestyle，they said．
Hui Zheng of Ohio State，the lead author of first study，said that the negative effects of obesity on health are greatest for young people．
63．The underlined word"detrimental"in Paragraph 2probably meansC．
A．importantB．fundamentalC．harmfulD．helpful
64．As for the 2001study，the general public wrongly think thatA．
A．it is healthy and protective for people to be very overweight
B．people with a BMI of 27or more are classified as overweight
C．senior adults with a BMI of 27lived longer than those either thinner or heavier
D．carrying extra pounds is a risk factor for many types of cancer and other diseases
65．What can we learn from the two new studies？D
A．It's difficult for seniors who have a so-called healthy weight to have a long life span．
B．It's most dangerous for normal-weight people to continue to lose weight．
C．The two studies are based on and in agreement with previous studies．
D．The second one recommends overweight and obese adults work out and lose weight．
66．What does the passage mainly tell us？B
A．The negative effects of obesity on health are greatest for young people．
B．Being slightly overweight may bring some health benefits for seniors．
C．It is harmless for overweight young people to continue to gain weight．
D．People at a healthy weight should intentionally put on extra weight．
