Well I am a Nurse and I have been encouraging vitamin supplements and protein bars, drinks, and shakes to my patients with wounds for years. Our diet is composed of millions of substances that are part of a biological network. I have been clinging to adding protein to my morning shakes which are otherwise fairly healthy — fruit, green vegs, nuts etc. Unfortunately the source from which the "natural flavors" come does not have to be listed. Then again meeting daily protein requirements even if not the exaggerated ones is key for strength training. By logic, hunters would have a a very rich protein diet.
Let’s call this babe, Coffee Lovers Protein Shake.
There are a few that appear to be mildly effective. This includes Caffeine, Green Tea and Glucomannan (a fiber that can reduce appetite). However, the results are usually weak and inconsistent and certainly nothing to get excited about.
At the end of the day, the only thing that is really proven to help you lose weight is changing your diet. Exercise can help too, but what you eat is by far the most important.