Sara14 - I love to workout and am also running a half marathon this May. I need extra protein in my diet, and whey protein is a high quality EASY source, when you're not always able to eat/cook meat. I've enjoyed having a protein shake for breakfast in the past, but the brands I've tried have always upset my stomach or caused bloating in some way.
In doing research, I've found that whey itself has extremely low levels of lactose (which is what causes intolerance), and should be safe for people with an intolerance to milk. So what I'm left believing is that it's all the other additives-artificial sweeteners-fillers that are causing my discomfort.
Like I said in a previous post, I'm trying for the first time a grass-fed, whey protein concentrate that I'm hoping will sit well with my digestive tract:)