diff --git a/src/preserves/pegs.nim b/src/preserves/pegs.nim
index 09a472e..7e62470 100644
--- a/src/preserves/pegs.nim
+++ b/src/preserves/pegs.nim
@@ -34,7 +34,7 @@ grammar "Preserves":
 
   Boolean <- '#' * {'f', 't'} * &delimiter
 
-  nat <- '0' | (Digit-'0') * *Digit
+  nat <- +Digit
   int <- ?('-'|'+') * nat
   frac <- '.' * +Digit
   exp <- 'e' * ?('-'|'+') * +Digit