Eyeing Portions

So today I had lunch at Sharky's with a co-worker. Ordered a side of black beans and a side of brown rice. Seemed very sensible, and I ate and we talked and it wasn't until later when it was time to write it down that I realized I didn't have a clue what the portion size was. I searched online for Sharky's side of beans and couldn't find it. So I settled with a cup of each and wrote down those numbers. But the numbers really added up! I didn't feel like I'd eaten 458 calories (though you never do...). This is why it's easier to prepare my food at home. But if this way of eating is going to be sustainable I really have to become better at eyeing portion size.  After all, a lunch of organic black beans and brown rice is great, and inevitably I'll be eating in restaurants and at friends' houses etc. I can always look up the calories of a food online, but being able to know whether it was a cup or half a cup makes a big difference - and I'm not going to bring a digital scale with me everywhere I go. As possibly bizarre as it sounds, I'm thinking about doing some practice drills. Pour a random amount of beans in a bowl, guess, then measure. Crazy?