Looking on the internet deeply has found these results:

I haven't eaten that in a long time. is the most popular phrase on the web.

I haven't ate that in a long time. 10 results on the web	I haven't eaten that in a long time. 13 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	Aug 31, 2005 ... Robyn. BEEF STEW AND RICE! I haven't eaten that in a long time but I think I'd still like it. Ooohh beef stew...yummy. Feb 5, 2014 ... ... chewing gum, soft drinks, peanut butter, cakes, frozen desserts, sauces, mayo, even toothpaste, although I haven't eaten that in a long time). ... food (e.g., bread, chewing gum, soft drinks, peanut butter, cakes, frozen desserts, sauces, mayo, even toothpaste, although I haven't eaten that in a long time).

I haven't ate that in a long time.

10 results on the web

I haven't eaten that in a long time.

13 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

Aug 31, 2005 ... Robyn. BEEF STEW AND RICE! I haven't eaten that in a long time but I think I'd still like it. Ooohh beef stew...yummy.
Feb 5, 2014 ... ... chewing gum, soft drinks, peanut butter, cakes, frozen desserts, sauces, mayo, even toothpaste, although I haven't eaten that in a long time).
... food (e.g., bread, chewing gum, soft drinks, peanut butter, cakes, frozen desserts, sauces, mayo, even toothpaste, although I haven't eaten that in a long time).