To solve the problem where Kate and Isaac share 495 sweets, with Kate getting 20% more sweets than Isaac, and finding out how many sweets Isaac gets, follow these steps:

Let Isaac's share be $x$.

Kate gets 20% more than Isaac, so she gets $x + 0.2x = 1.2x$.

The total number of sweets is $x + 1.2x = 2.2x = 495$.

To find $x$, solve:

$2.2x = 495$

$x = \frac{495}{2.2}$

$x = 225$

So, Isaac gets 225 sweets. The correct answer is option D.