0First you have to fix the grammar. Then compare.02br 01i00It has been a long time since I 01b00have02b00 eaten02i00 is about the same in meaning as 01i00It has been a long time since I ate02i00.02br 00(You can add the 01i00last02i00 in both if you want, but it's basically unnecessary
1i00It has been a long time since I 01b00have02b00 eaten02i02br 02br 00or similar is many time reduced by using 01b00tense simplification in the subordinate02b00 (see Swan) to02br 01i00It has been a long time since I 01b00ate02b02i00.0-