function insert_form() {
global $wpdb;
$table_name = $wpdb->prefix . "food_resarved";
$wpdb->insert( $table_name, array('id'=>'','name'=> wp_get_current_user()->user_firstname ,
    'lastname'=> wp_get_current_user()->user_lastname ,'post_title'=> $_POST['post_title'],'food_selected'=> $_POST['food'] ,
    'guest_number'=>5,'email'=> wp_get_current_user()-> user_email ), array( '%d', '%s', '%s' , '%s' , '%s' , '%s' , '%s' ) );