SparkPeople.com

There are a number of weight-loss communities online, but most charge for access to their meal plans and resources. SparkPeople.com is a free website that gets excellent reviews from users and experts. Instead of being wedded to a particular diet plan, users choose from a variety of meal plans that can be customized for special dietary needs including vegetarian, low-cholesterol or low-sodium. If you don't like a particular meal in your plan, you can swap it out for other meal choices with similar calorie contents.

Reviewers say the online user community is active, engaged and motivating; users can join teams and compete for points and virtual trophies when they meet weight-loss or fitness goals. The fitness component of SparkPeople.com also gets high marks for helping to advance an overall lifestyle change. However, some users complain that the site is hard to navigate, and it can be time-consuming to input all of your daily food and exercise activities each day. If you can spend the money, Weight Watchers (*Est. $30 to join, plus weekly fees) also gets good reviews for its online community, and is the top-rated diet plan overall. eDiets.com (*Est. $19 per month) gets excellent reviews, as well.

Good Housekeeping evaluates SparkPeople.com in a comparative test of the best diet websites. While the commentary is brief, editors clearly list their likes and dislikes. User reviews are another good source of information, and Viewpoints.com has the best coverage. DietsInReview.com offers fewer reviews.