My Cookie was diagnosed with lymphangectasia in Dec. 2011. To my knowledge, Hill's KD is not a recommended food for it, but I could be wrong. I have a feeling it is probably too high fat. I believe that Royal Canin low fat is good...but it has been some time and I would not suggest you use that unless you speak with your vet.
In speaking with the specialist at the time Cookie was diagnosed, I had asked if it would be better if I home cooked for her and he did say that home cooking would be ideal. I did a consult with a board certified vet nutritionist and she formulated a diet for Cookie that she is still on and thriving! Her recent blood work was awesome! Albumin 3.7 I swear it is the diet! I don't think it is a good idea to get a diet from another person....it really should be formulated for your individual pup and his needs.
Here is the thread about Cookie:
http://www.yorkietalk.com/forums/sic...ia-update.html
To find a board certified vet nutritionist if your vet does not know one:
American College of Veterinary Nutrition