Subway, Mableton

When he cofounded his first sandwich shop in 1965—then called Pete's Subway—17-year-old Fred DeLuca planned to use his profits to pay his way through med school. But the combination of quality ingredients and friendly service proved so popular that nine years later, he and his partner found themselves in charge of 16 locations across Connecticut, and Fred left behind his doctoring plans for good.

Today, Subway restaurants number about 45,000 around the world. At each location, staffers pile sliced ham, marinara-slathered meatballs, and other fillings onto loaves of bread before customizing subs with fresh toppings plucked from chilled containers. They free crisp veggies from bread's overprotective embrace by creating salads, and they send entrées to tables along with crunchy chips or apple slices.

Subway's website also facilitates health-conscious eating by listing each item's nutritional information online.