3 Fat Chicks on a Diet - Weight loss support, forums, blogs, articles and more.

Low Carb Site - A community forum dedicated to low carb and Atkins diet.

Low Carber Forums -  Support for Atkins diet, Protein Power, Neanderthin (Paleo Diet), CAD/CALP, Dr. Bernstein Diabetes Solution and any other healthy low-carb diet or plan.

MiniMins - Weight loss support forum, to help others lose weight with various different diets.

My Fitness Pal Message Boards - A very active fitness and weight loss community. Recommended ★★★★★.
 
Obesity Discussion - Forum to help people deal with their condition and daily lives. Posts cover medical research, studies, and nutrition tips.

Spark People Message Boards - A positive community for reaching goals.