What is a Nightshade Vegetable?

My workplace is having a fitness challenge for the employees for the month of May. One of the things you can do to earn points is participate in a cleanse. First of all, I am NOT a fad dieter. I eat what I want, when I want. I mock people who participate in cleanses and weird diets. My simple philosophy is moderation in all things except vegetables. (I figure binging on broccoli and green beans would probably do more good than harm, given my current eating preferences.) So this cleanse is called a macrobiotic cleanse. The girl at work who promoted this particular cleanse says it's "gentle and easy." The premise of the cleanse is that you don't want to eat extreme foods, just balanced foods. Extreme foods include nightshade vegetables (because everyone intuitively know what those are...I have learned they include bell peppers and tomatoes), sugar, white rice, honey, caffeine, alcohol, chocolate, dairy, hot spices, preservatives, gluten, poultry, meat, eggs, and salt. So what am I supposed to eat? Sea vegetables (again, everyone intuitively knows what constitutes a sea vegetable), beans, fruits, nuts, seeds, fish, and whole grains that aren't glutenous. In addition to all this, you are supposed to eat foods from your natural habitat, as in, I live in Colorado, so I should eat Colorado foods. The reason for this is your body has adapted to best process the foods from your local region. But I find some problems with this. Does this mean I should eat Colorado foods because I'm here, or does it mean I should eat Utah foods because I grew up in Utah and have lived 95 percent of my life there? And bison are local to Colorado, so why can I eat sea vegetables and not bison? And then, when I asked what some menu ideas were, my coworker suggested avocados (grown in tropical climates), brown rice (grown in wet climates), quinoa (from South America), and sushi (do I need parenthesis here?). While you ponder the merits of this "gentle and easy" cleanse, I am going to go mock my coworkers and binge on nightshade vegetables.