most known NEGATIVE side effects are mostly related to indigestion of lactose, the complex sugar found in all diary products. The human body digests lactose sugar with an enzyme known as lactase, and they are produced in the guts by the friendly bacteria. Some of us just do not produce that much lactase.
As a result, inability to digest lactose causes, inflatulence (loads of gas coming out from your behind :twisted: ), soft faeces and even diarrhea if serious. However, there could also be other reasons for these syndromes. It could be that the product itself is of poor quality, or worse, contaminated.
Some protein supplements do not contain what they claim to contain. Some contains alot of sugar or even loads of filler. The more the filler, the less the protein. (Fillers used are usually, ashes, cocoa powder, lecithin, artificial flavour)
Over-dosing on protein is not something that happens immediately. It happens over time.... as you eat more than u should, u realise u have a thinner wallet. But seriously speaking, effects of long-term abuse of whey protein have not been clinically tested. But as with all things, moderation is the way to go.
The only biggest side effects of normal use of whey protein known to date, is more lean muscle mass. :lol:
But you must understand that wide spread retail level protein supplementation did not occur until the 80s, and whey came on in a big way only in the 90s. So long term use by humans are not known.
Read the following article for a more complete picture.
http://www.formerfatguy.com/articles/protein-sups-vs-foods.asp
