Chipotle's CEO says customers can just ask for extra food. I put it to the test. I tested Chipotle's portion sizes after its CEO said customers should "just ask" for more food. Katherine Tangalakis-Lippert Chipotle's CEO went viral this week after saying customers should ask for more food if they want it. I went to three different locations to put his promise of "abundance" to the test. I found that portion sizes — and whether you can get extra add-ons for free — depend on who you ask. The first Chipotle employee I spoke to started scooping more steak into my bowl before I could finish my sentence. "Can I get a little extra meat?" I asked. Without hesitation, the worker reached for another full scoop. I stopped her midway through. I wasn't actually trying to order my bowl "double protein" style. I was testing a claim made this week by Chipotle CEO Scott Boatwright , after years of complaints that the chain's portions have gotten stingier.…