The contest is supposed to have ended on 10th September but you can still play the quiz.
Answer ten questions, which are a mixture of fairly complicated to really tough in the fastest possible time to win a place on the leaderboard and a hamper of goodies. There is no limit to how many times you can participate and from the 'maximum attempts' tab it appears that a few users have been more than a bit enthusiastic with their attempts!
Over a 100 attempts sounds quite obsessive to me! But it shows that the quiz is fun to do and the questions vary each time so the variety and fairness are maintained.
You can also invite your friends to play the quiz and thus help them improve their health awareness as well.
The timer ensures that there is a limit to how much you can cheat with Google. And the nature of the contest is such that even if you do, it doesn't really matter because you're still upgrading your health quotient.
What I really like about the quiz is that after every question, not only do they tell you if you are right or wrong but they also give you a host of other information on the matter that really improves your knowledge.
Scope for Improvement
A quiz is good but it's also a tad too simple. The contest could include visual questions to spice things up a bit. They could make it more elaborate by introducing different categories.