Aspartame
This is simply an evil invention. There is no reason anyone should be consuming this foul-tasting sugar-substitute, unless you want to cause an array of terrible health conditions.
Aspartame really does cause cancer and there are numerous research studies that confirm this. It is a much better idea to leave the aspartame alone altogether.
Olestra
Olestra is nothing more than a fat substitute. It is added to products that are high-fat, in order to lower or completely remove the fat content. While that may sound like a great idea, it really is not.
Even though it can lower fat content, it can cause a heap of worse conditions, including stomach pains and even diarrhea. Thankfully, most countries have done their bit to remove products that contain Olestra from stores, although, there are some places that you can still find products containing this horrible ingredient if you look hard enough.