The biggest difference between Ayurvedic and (most) Western nutrition is that Ayurveda provides customized dietary recommendations based on your individual constitution.
Most Western diets are one-size-fits-all. While you might find some diets in the West that provide some variance for different body types, they are few and far between. (Perhaps the most well-known of these is the Blood Type Diet, with different dietary recommendations based on blood type.)
The U.S. government, for example, simply provides general nutrition guidelines that are meant to apply to the entire population. Other popular diets, from the South Beach Diet to Paleo, also offer generalized recommendations. For example, if you are eating Paleo, you are expected to consume a lot of meat protein, regardless of your individual needs.
By focusing on individual constitutions, Ayurveda is unique in its approach.