Try these two:www.fitness.comwww.sparkpeople.com
Not online, but it s been proved effective time and time again.Excercise more.Eat less.Always works :-)If you want to keep track of how you re doing, this works well:http://www.fitday.com/
Try this free website where you can track your calories eaten and burned through exercise and also get support from chat boards with other members called http://www.sparkpeople.comIt s an excellent resource, full of good tips, tools and advice and even shows demonstrations of proper exercise and strength training techniques and it really got me motivated after years of demotivation. I don t know what it is about this site, but I ve been exercising nearly everyday since I started it.I ve lost 10 lbs so far, been on it for 2.5 weeks!