Ben & Jerry's, known for its ice cream filled with chunks of fudge, brownies or cookie dough, is the latest brand to launch a slimmed-down version of its treats. It's an effort to better compete with Halo Top, a low-calorie, low-sugar ice cream that is growing fast. Halo Top's entire pints have fewer than 400 calories, and it emphasizes the full calorie count on the front of its package — a move others are mimicking.