I have found some brands get foamier than others, so you might try a different brand of protein powder.  Also, they tend to get foamier in the blender than if you just put them in a cup with a lid and shake.  Some brands don't seem to mix as well if you just shake them, but others do fine that way.

If you mix a shake and then let it sit in the fridge for a while, some of the foam will dissipate.

I was just going to say the same thing:  I use synthrax nectar -- and it gets way too foamy.  I mix it and set in the fridge for a bit.  Works great!

Syntrax Nectar is one I found got super foamy in the blender.  It is much less foamy, I think, if I just put it in a cup with a lid and shake.  And it mixes really well just shaking it.  I love some of the Syntrax flavors, they are my favorite protein drinks. 

I agree its the worst!  Try using your pulse button, it won't get as bad.  Also another idea which I actually do, get yourself a 32 ounce rubbermade drink holder.  Put three scoops of powder in your blender to 16 ounces of your liquid (milk or water).  Pulse it (it does foam some).  Add 8 ounces of your preferred liquid to your rubbermade and then add your contents of the blender.  Make this the night before and by morning the foam is gone.  An added bonus, if you are allowed fat free milk, by using this you may find that you have gotten your protein in for the day.  The protein powder I use is 27 grams of protein a scoop, and the milk is 9 grams per 8 ounces.  Thus the 32 ounces is 108 grams of protein. 

I put my powder and milk in a shaker bottle and shake well then put it in the freezer and let it get real cold and sometimes kind of slushie.  The foam will disappear in the freezer.  Last night I added a tablespoon of unsweetened cocoa to my vanilla protein shake and it was great.  I put it in the freezer for a while.  God bless you, I hope you find what works.

The first post-op shake that I made had the foam and, I learned very quickly how if felt to swallow those little air bubbles.  I looked on this forum and saw that someone had suggested using an immersion blender.  That did the trick.  I put the stick blender so it is sitting on the bottom of the glass and just mix for a second and I have minimal foam.  It works until you are able to tolerate a little more air.

Another suggestion is to simply cover your shake and let it sit in the refrigerator for awhile until the bubbles have disolved.

I hate the foam on top of shakes too.  Someone suggested getting a Bullet blender so right now my favorite protein shake is vanilla Matrix, skim milk, a little bit of ice, and frozen strawberries.  Taste just like a strawberry milkshake.  Love it.  Its the only way I fix my shakes now.

EAS myloplex carb advantage (i.e. the low carb one) doesnt do this in the blender on low

I hardly ever use a blender, when I do, I pour the shake through a wired trainer first.