diff --git a/foamlib/_files/_files.py b/foamlib/_files/_files.py
index af2cc90..db5a7f2 100644
--- a/foamlib/_files/_files.py
+++ b/foamlib/_files/_files.py
@@ -195,7 +195,7 @@ def __setitem__(
             elif not isinstance(keywords, tuple):
                 keywords = (keywords,)
 
-            if not self and keywords[0] != "FoamFile":
+            if not self and "FoamFile" not in self and keywords[0] != "FoamFile":
                 self.header = {
                     "version": 2.0,
                     "format": "ascii",
@@ -278,7 +278,11 @@ def __delitem__(self, keywords: Optional[Union[str, Tuple[str, ...]]]) -> None:
     def _iter(self, keywords: Tuple[str, ...] = ()) -> Iterator[Optional[str]]:
         _, parsed = self._read()
 
-        yield from (k[-1] if k else None for k in parsed if k[:-1] == keywords)
+        yield from (
+            k[-1] if k else None
+            for k in parsed
+            if k != ("FoamFile",) and k[:-1] == keywords
+        )
 
     def __iter__(self) -> Iterator[Optional[str]]:
         return self._iter()
@@ -310,7 +314,9 @@ def __fspath__(self) -> str:
     def as_dict(self) -> FoamFileBase._Dict:
         """Return a nested dict representation of the file."""
         _, parsed = self._read()
-        return parsed.as_dict()
+        d = parsed.as_dict()
+        del d["FoamFile"]
+        return d
 
 
 class FoamFieldFile(FoamFile):
diff --git a/tests/test_files/test_files.py b/tests/test_files/test_files.py
index 9897ad3..59ec4d5 100644
--- a/tests/test_files/test_files.py
+++ b/tests/test_files/test_files.py
@@ -26,11 +26,12 @@ def test_write_read(tmp_path: Path) -> None:
 
     d["key"] = "value"
     assert d["key"] == "value"
-    assert len(d) == 2
+    assert len(d) == 1
     assert "key" in d
-    assert list(d) == ["FoamFile", "key"]
+    assert list(d) == ["key"]
+    assert "FoamFile" in d
     del d["key"]
-    assert len(d) == 1
+    assert not d
     assert "key" not in d
     with pytest.raises(KeyError):
         del d["key"]