Q:

what's wrong with this $_POST and sql code?

The following code runs fine, but it doesn't update the mysql database. 
The sql query isn't the problem because I commented out the if statement and the MySQL database updates fine. It has to do with the $_POST array. I have a feeling when I put in the $row["id"] into the $_POST array, it's not going in nicely. 
if (isset($_POST["
         {$row["id"]}
         "]) && !empty($_POST["
                      {$row["id"]}
                      "])){
  print_r($_POST);
 $food_id = $_POST[$row["id"]];

 $query = "INSERT INTO `users_foods`
VALUES('','1','7','','','','')";

//$_SESSION['user_id']

   $query_run = mysql_query($query);

}

A:

{$row["id"]}

should be 
{$row['id']}

