She looks fairly healthy. More so than one supposedly walked hundreds of miles in past few weeks. So she is eating something.......
If you were walking forty miles a day (flat surface) for two or three weeks, without losing weight, you’d have to consume around 3,000 to 3,500 calories per day. In her case, I’d take a guess that she walked no more than two or three days, and the rest spent on some truck/bus.
All of this is pretty faked-up. Maybe a quarter of the crowd are walking just to be dramatic in nature, for pictures. But they probably only walk every fourth-day, and the rest all have some truck/bus arrangement.