diff --git a/src/grib_api_internal.h b/src/grib_api_internal.h
index 3b8fae3ca..0c8fcf17c 100644
--- a/src/grib_api_internal.h
+++ b/src/grib_api_internal.h
@@ -40,9 +40,9 @@ extern "C" {
 
 #if IS_BIG_ENDIAN
 #if GRIB_MEM_ALIGN
-#define FAST_BIG_ENDIAN 0
-#else
 #define FAST_BIG_ENDIAN 1
+#else
+#define FAST_BIG_ENDIAN 0
 #endif
 #endif