mak david - I am shocked that Singaporean students waste food in this manner at games! There are so many field games that don't require wasting food this way...I wonder why they used watermelon and lettuce! Scavenger hunts tend to be my favorite default. Let me know if you need more ideas.
Sachin Bhide - I recently read a book about how to influence others (https://www.amazon.com/Influencer-Power-Change-Anything-First-ebook/dp/B000UZJQSM). This prescriptive model uses a strategic approach from motivation and ability at three levels: personal, social, and structural. It reminded me that when we prepare for change, we should take into account all of these perspectives.
Saumya Singhal - the psychology behind consumer habits and pricing models is fascinating and there's a ton of literature out there. Economics isn't my forte, but I stumbled upon this blog that summarizes how if restaurants offer a middle portion size, then it could lead to a less wasteful model too: https://www.jeremysaid.com/blog/customers-will-choose-middle-offer/