A lot of meizitang strong advanced pills also make the use of very strong laxatives and diuretics. This is because they work to get rid of fecal waste and also water weight. So when you step on your bathroom scales you'll see a noticeable improvement in your weight.
The problem is that these pills shouldn't ever be taken over the long term as they can cause you ill-health. They certainly won't help you get rid of fat.
This is why you should look at the ingredient list and research each and every one listed. They can sound very impressive when listed on websites but often they become less than impressive when you learn more about them.
For instance, let's look at trim-fast, you'll see that this is another name for Bitter Orange. It's become very popular in diet pills since Ephedra was banned in a number of countries including the US. However Citrus aurantium has never been proven as being of use for weight loss and it's also been linked to a number of negative side-effects.