I weigh much more than her, but 4000 wouldn't be near enough if I was running marathon-training volume. Especially if you're doubling, that stuff revs up your metabolism all day long. It also makes it harder to digest food and get all the calories you eat. And it reduces the "anabolic" time of low metabolism to put those calories to use building and restoring tissue. I'd need probably about 6000.
Plus if your relative intake of carbs is high, you might not be getting enough quality protein to recover, no matter how many calories you eat.
A doctor who I don't have a link for wrote on the internet that a diet with excessive calcium compared to magnesium results in bones that are chalky and brittle. Magnesium deficiency is undetectable, and athletes should supplement because most food sources are unreliable, and commercial water sources are usually soft. Bones with enough magnesium don't break easily.