diff --git a/helpers/entity.group.inc b/helpers/entity.group.inc
index fa41f10..e1b3149 100644
--- a/helpers/entity.group.inc
+++ b/helpers/entity.group.inc
@@ -78,6 +78,36 @@ function group_load_by_member($uid, $type = NULL) {
 }
 
 /**
+ * Get Group entities id's for a provided outsider account.
+ *
+ * @param int $uid
+ *   The id of the user entity.
+ * @param string $group_type
+ *   Optionally provide a group type to filter group ids.
+ *
+ * @return array
+ *   An array of group entities ID for the provided outsider account.
+ *   Otherwise an empty array.
+ */
+function group_get_gids_by_outsider($uid, $group_type = '') {
+  $query = db_select('groups', 'g')
+    ->fields('g', array('gid'));
+
+  if ($group_type) {
+    $query->condition('g.type', $group_type);
+  }
+  $query->leftJoin('group_membership', 'gm', 'g.gid = gm.gid');
+  $query->condition(db_or()
+      ->isNull('gm.uid')
+      ->condition('gm.uid', $uid, '<>')
+    )
+    ->groupBy('g.gid')
+    ->orderBy('g.gid', 'ASC');
+
+  return $query->execute()->fetchCol();
+}
+
+/**
  * Save a group.
  */
 function group_save($group) {
diff --git a/implementations/group.node.inc b/implementations/group.node.inc
index 1d53eba..9b76962 100644
--- a/implementations/group.node.inc
+++ b/implementations/group.node.inc
@@ -111,104 +111,109 @@ function group_node_access($node, $op, $account) {
  * @see group_node_access_records().
  */
 function group_node_grants($account, $op) {
-  $grants = array();
+  static $cache = array();
 
-  // If the user can bypass group access, he only needs the master grant.
-  if (user_access('bypass group access', $account)) {
-    return array('group:bypass' => array(GROUP_BYPASS_GRANT_ID));
-  }
+  if (!isset($cache[$account->uid][$op])) {
+    $grants = array();
+    $cache[$account->uid][$op] =& $grants;
 
-  // Gather the machine names of all node types.
-  $node_types = array_keys(node_type_get_types());
+    // If the user can bypass group access, he only needs the master grant.
+    if (user_access('bypass group access', $account)) {
+      return array('group:bypass' => array(GROUP_BYPASS_GRANT_ID));
+    }
 
-  // Gather all groups the user is a member of.
-  $member_groups = group_load_by_member($account->uid);
+    // Gather the machine names of all node types.
+    $node_types = array_keys(node_type_get_types());
 
-  // Provide grants for groups the user is an outsider to.
-  foreach (group_types() as $type => $group_type) {
-    $outsider_groups = group_load_by_type($type);
-    $outsider_gids = array_diff_key($outsider_groups, $member_groups);
+    // Provide grants for groups the user is an outsider to.
+    foreach (group_types() as $type => $group_type) {
+      // Gather all groups of this group type the user is an outsider of.
+      $outsider_gids = group_get_gids_by_outsider($account->uid, $group_type->name);
+      if ($outsider_gids) {
 
-    if ($outsider_gids) {
-      // If the user is an admin, he requires no further specific grants.
-      if (in_array('administer group', $group_type->outsider_permissions)) {
-        foreach ($outsider_gids as $gid) {
-          $grants['group:administer'][] = $gid;
+        // If the user is an admin, he requires no further specific grants.
+        if (in_array('administer group', $group_type->outsider_permissions)) {
+          foreach ($outsider_gids as $gid) {
+            $grants['group:administer'][] = $gid;
+          }
+          continue;
+        }
+
+        foreach ($node_types as $node_type) {
+          // Shorten variable name for readability's sake.
+          $permissions = $group_type->outsider_permissions;
+
+          // Allow the user to view content of this type.
+          if ($op == 'view' && in_array("view $node_type", $permissions)) {
+            foreach ($outsider_gids as $gid) {
+              $grants["group:$node_type:view"][] = $gid;
+            }
+          }
+          // Allow the user to edit any content of this type.
+          elseif ($op == 'update' && in_array("edit any $node_type", $permissions)) {
+            foreach ($outsider_gids as $gid) {
+              $grants["group:$node_type:update"][] = $gid;
+            }
+          }
+          // Allow the user to delete any content of this type.
+          elseif ($op == 'delete' && in_array("delete any $node_type", $permissions)) {
+            foreach ($outsider_gids as $gid) {
+              $grants["group:$node_type:delete"][] = $gid;
+            }
+          }
+          // Allow the user to edit own content of this type.
+          elseif ($op == 'update' && in_array("edit own $node_type", $permissions)) {
+            foreach ($outsider_gids as $gid) {
+              $grants["group:$gid:$node_type:update"][] = $account->uid;
+            }
+          }
+          // Allow the user to delete own content of this type.
+          elseif ($op == 'delete' && in_array("delete own $node_type", $permissions)) {
+            foreach ($outsider_gids as $gid) {
+              $grants["group:$gid:$node_type:delete"][] = $account->uid;
+            }
+          }
         }
+      }
+    }
+
+    // Gather all groups the user is a member of.
+    $member_groups = group_load_by_member($account->uid);
+
+    // Provide grants for groups the user is a member of.
+    foreach ($member_groups as $group) {
+      // If the user is an admin, he requires no further specific grants.
+      if (group_access('administer group', $group, $account)) {
+        $grants['group:administer'][] = $group->gid;
         continue;
       }
 
       foreach ($node_types as $node_type) {
-        // Shorten variable name for readability's sake.
-        $permissions = $group_type->outsider_permissions;
-
         // Allow the user to view content of this type.
-        if ($op == 'view' && in_array("view $node_type", $permissions)) {
-          foreach ($outsider_gids as $gid) {
-            $grants["group:$node_type:view"][] = $gid;
-          }
+        if ($op == 'view' && group_access("view $node_type", $group, $account)) {
+          $grants["group:$node_type:view"][] = $group->gid;
         }
         // Allow the user to edit any content of this type.
-        elseif ($op == 'update' && in_array("edit any $node_type", $permissions)) {
-          foreach ($outsider_gids as $gid) {
-            $grants["group:$node_type:update"][] = $gid;
-          }
+        elseif ($op == 'update' && group_access("edit any $node_type", $group, $account)) {
+          $grants["group:$node_type:update"][] = $group->gid;
         }
         // Allow the user to delete any content of this type.
-        elseif ($op == 'delete' && in_array("delete any $node_type", $permissions)) {
-          foreach ($outsider_gids as $gid) {
-            $grants["group:$node_type:delete"][] = $gid;
-          }
+        elseif ($op == 'delete' && group_access("delete any $node_type", $group, $account)) {
+          $grants["group:$node_type:delete"][] = $group->gid;
         }
         // Allow the user to edit own content of this type.
-        elseif ($op == 'update' && in_array("edit own $node_type", $permissions)) {
-          foreach ($outsider_gids as $gid) {
-            $grants["group:$gid:$node_type:update"][] = $account->uid;
-          }
+        elseif ($op == 'update' && group_access("edit own $node_type", $group, $account)) {
+          $grants["group:$group->gid:$node_type:update"][] = $account->uid;
         }
         // Allow the user to delete own content of this type.
-        elseif ($op == 'delete' && in_array("delete own $node_type", $permissions)) {
-          foreach ($outsider_gids as $gid) {
-            $grants["group:$gid:$node_type:delete"][] = $account->uid;
-          }
+        elseif ($op == 'delete' && group_access("delete own $node_type", $group, $account)) {
+          $grants["group:$group->gid:$node_type:delete"][] = $account->uid;
         }
       }
     }
   }
 
-  // Provide grants for groups the user is a member of.
-  foreach ($member_groups as $group) {
-    // If the user is an admin, he requires no further specific grants.
-    if (group_access('administer group', $group, $account)) {
-      $grants['group:administer'][] = $group->gid;
-      continue;
-    }
-
-    foreach ($node_types as $node_type) {
-      // Allow the user to view content of this type.
-      if ($op == 'view' && group_access("view $node_type", $group, $account)) {
-        $grants["group:$node_type:view"][] = $group->gid;
-      }
-      // Allow the user to edit any content of this type.
-      elseif ($op == 'update' && group_access("edit any $node_type", $group, $account)) {
-        $grants["group:$node_type:update"][] = $group->gid;
-      }
-      // Allow the user to delete any content of this type.
-      elseif ($op == 'delete' && group_access("delete any $node_type", $group, $account)) {
-        $grants["group:$node_type:delete"][] = $group->gid;
-      }
-      // Allow the user to edit own content of this type.
-      elseif ($op == 'update' && group_access("edit own $node_type", $group, $account)) {
-        $grants["group:$group->gid:$node_type:update"][] = $account->uid;
-      }
-      // Allow the user to delete own content of this type.
-      elseif ($op == 'delete' && group_access("delete own $node_type", $group, $account)) {
-        $grants["group:$group->gid:$node_type:delete"][] = $account->uid;
-      }
-    }
-  }
-
-  return $grants;
+  return $cache[$account->uid][$op];
 }
 
 /**