Embedded objects typically have a "natural" size. For example a 200x200 image with 100 dpi has a natural size of 2x2 inches. Similarly, a MathType formula has a natural size in which its native font size is displayed correctly, i.e. such that the 12pt letter "x" in the formula is also displayed as 12pt in Visio.
Now, if for example you scale a MathType formula, its font size and kerning are all messed up. Is there a way to reset the size of an object to its "natural size"? In Word 2010 you can do this using in the "Format Object" dialog. Go to the "Size" tab and click the button labeled "Reset", or enter 100% in both X and Y dimension.
Is there a way to do the same thing in Visio?