Everyone's heard that the secret to weight loss is to eat slowly so you feel full and eat less, but that's sometimes easier said than done. The DDS System is a custom-fitted retainer-like dental device that you wear on the roof of your mouth during meals to create a physical barrier against taking large bites of food. Some tests have shown that people eat about 25% less when wearing a DDS System. The device is nearly invisible once it's inserted but some users have complained that it's uncomfortable and makes it hard to speak clearly. It's probably a good idea to leave it at home and spare your dinner companions.

If the DDS seems a bit extreme, there's always the Powerseed. The 'seed, as I like to call it, blinks and makes soft sounds so you can time your bites, very much like a metronome for eating. Every five minutes you get a special signal that's supposed to prompt you to evaluate your hunger level. Sounds like a training tool for eating disorders.