For many of us, the start of a new year signals an annual rejuvenation of our health consciousness. Following a six-week (or longer) stretch of celebratory dinners, wine-soaked holiday lunches and general overindulgence, we instinctively reach for the reset button as soon as the New Year’s Eve hangover dissipates—vowing to cut the carbs, speed up the treadmill and let the bar cart go un-replenished as a means of penance for the December bacchanalia.

But then along comes Twelfth Night and t...