diff --git a/contrib/summerschool/foods/Makefile b/contrib/summerschool/foods/Makefile
index 5f42041ae..5738bc281 100644
--- a/contrib/summerschool/foods/Makefile
+++ b/contrib/summerschool/foods/Makefile
@@ -2,7 +2,7 @@
 all:: Foods.pgf
 
 Foods.pgf: Foods???.gf
-	gf -make -s Foods???.gf
+	gf -make -s -optimize-pgf Foods???.gf
 
 clean:
 	rm -rf *.gfo Foods.pgf