If your thoughts turn to supplements or herbal remedies, keep in mind that research gives many of them mixed reviews. In some cases, there isn't a lot of science to back up the claims, and some have health risks.
Although green tea extract is usually well tolerated, it can cause stomach pain, constipation, and nausea. However, a more recent review of randomized control trials indicated that glucomannan did not appear to result in significant weight loss. Studies appear to be conflicting on whether glucomannan can aid in weight loss, however. It works by absorbing water in the gut, leading to a feeling of fullness that may prompt people to eat less.