A、How to reduce weight by 9 kilos. B、How to keep their new weight. C、How to find a counselor to lose weight. D、How to visit a we

For many people trying to shed a few kilos, it’s hard enough to lose the weight, but many experts say it’s even harder to keep the weight off. Now, a new study indicates that the Internet can help. People in the study had already lost an average of 9 kilos. The challenge they faced was maintaining their new weight. To test various strategies, researchers randomly assigned participants to one of three groups. One group was told to meet with a counselor once a month. Another group was asked to try a weight management website. People in the third group were on their own. Those who got personal counseling did the best, regaining about 4 kilos. The website users regained about 5.2 kilos overall, not much better than the third group, which had no structured weight maintenance program. But study author Kristine says those averages conceal significant differences within the group of website users. She says the online tool was very effective for those who used it at least once a month. Users visiting the website created for this study were asked to enter their weight, the food they’d eaten, and their physical activity. She also says that, when the upfront costs of developing a website like that are spread over a lot of participants, the web approach would likely be cheaper than individual counseling. Kristine’s study on Web-based weight loss management is published in the Journal of Medical Internet Research.
20. What s the main challenge for the participants in the study?
21. What did the test find in the end?
22. Which of the following does Kristine probably agree with?