When I am sufficiently motivated, I make myself a green smoothie in the morning and bring it to school in a glass jar. Yes, it's a glass canning jar, and yes, I carry it around with me throughout the day.
(what is a green smoothie, you ask? um, try one - it's a blended-together mix of greens/fruit/berries/seeds/nut butter/whatever you want. although they range from simple [double handful of spinach+water+2 bananas+apple] to unusual [mango+kale+soy milk+raspberries+hot pepper+apple], they are very tasty.)
As you might expect, seeing a person drinking a bright green sludgy substance on a regular basis is a cause for curiosity or concern. Most of the time, I explain what exactly is in the jar and offer the inquisitive person a taste.
However...when the associate dean of the vet school (a wizened old ambulatory practitioner) raised an eyebrow and inquired about my drink, I instead said:
"Oh, I dipped this out of the surgery rumenotomy bucket this morning. It's delicious!"