Zucchini is the most popular summer squash in the United States and Europe. Zucchini is a very low calorie vegetable, with only 17 calories per 100 g. It contains no saturated fats or cholesterol, and the skin of the zucchini is a good source of dietary fiber. Select small to medium-sized zucchini featuring shiny, bright green skin, firm and heavy in hand. The best size for zucchini is 6 to 8 inches long and 2 inches or less in diameter. The larger sizes are good for stuffing. Avoid overly mature zucchini with pitted skin or those with soft and wrinkled ends, as they indicate old stock and state of de-hydration.