Not at most places, but normally fries are a side rather than the main thing that you’re eating. That being said, it varies.

I remember a hamburger place at the university I attended. They had this big sign on the wall listing the number of tons of potatoes they had served. They had something of a reputation for their fries.

One day, they had this alumni event and a lot of older people showed up. One – clearly health conscious – elderly lady tottered up to the counter and asked for a small water, a small garden salad with no dressing, and a small fries with no salt. I leaned against the wall and started laughing to myself, just waiting for this. The guy comes out, puts down the lady’s plastic tray on the he counter. He puts a – fairly small – cardboard little container on the tray. Then he starts pouring fries over the thing until the cardboard container is lost to sight and there’s just a huge mound of fries on her tray. The lady looks at her tray “Err…I think that there was some mistake. I ordered a small”. The guy: “Lady, we sell three sizes of fries. Small, medium, and large. And that is a small.”. She says “oh, my” and totters off with her order.

A large at that place would be a dinner for maybe three hungry college guys, without anything else going with it. But that’s atypical.