Top 15 Best Diet & Weight Loss Websites Here are top 15 most popular diet and weight loss websites. 1 Weightwatchers weightwatchers.com 2 Cronometer cronometer.com 3 Eatthis eatthis.com 4 Loseit loseit.com 5 Fatsecret fatsecret.com 6 Fooducate fooducate.com 7 Noom noom.com 8 Optavia optavia.com 9 Yourketo yourketo.diet 10 Sparkpeople sparkpeople.com 11 Drfuhrman drfuhrman.com 12 Calorieking calorieking.com 13 Jennycraig jennycraig.com 14 Myfooddiary myfooddiary.com 15 Zonediet zonediet.com