I'm a 55 yr old male, very good shape, and I exercise frequently. For quite some time I've been using protein powder and have tried out different kinds. All of them were/are high-end brands.

Whenever I use the protein powder, I start to crash briefly after it is consumed, and I don't know why this happens. I usually drink it with milk, but it does the same with orange juice as well.

Feel free to ask any questions relating to my diet or such.