There are a couple of factors, but there is more to it. To use them, we need to know how light meters work, and how histograms work.
A histogram is not a light meter. A histogram shows the values how the reflected colors come out (NOT how they ought to come out). Colors do not reflect equally. A white polar bear in the snow in bright sun should be pretty bright, and near the right end of the histogram. A black cat in a coal mine should be pretty dark and at the left end. That is how accurate pictures should come out. Arbitrarily shifting all photos to the right end without concern how the colors ought to come out will overexpose some things.
Reflected light meters try to put everything (the average value of everything) in the middle. If you photograph three scenes which are 100% bright white, 100% dark black, and 100% middle gray, the light meter will try to put all three at about the middle. So that's not very precise either. White should come out high, black should come out low, and middle gray near the middle.
And camera histograms are of two types. One is a single gray histogram, which is a math manipulation to show how black&white film would reproduce the colors (called Luminance). It is very inaccurate regarding how the colors are reproduced, and it should be ignored in the camera. Another type shows three RGB histograms, which is how the colors actually come out, and should be the only one you look at. It is accurate (about how colors are reproduced, but does not know how they should be reproduced).