Yup, like they said, if you buy from the counter, you can ask them to trim it, or give you a lean cut. Just buy something that doesnt look too marbled.
If you buy from the shelves, for beef, buy Sirloin. Sirloin is usually 5% fat, chuck is 20% fat, and there is another one I think. They tell you the percentages on the package.
lean in general would be turkey, chicken (just cut the big clumpy white fat off it) tuna.