Exclude multiple categories from Google Product Feed

functions.php

<?php

function lw_gpf_exclude_product($excluded, $product_id, $feed_format) {
    // Return TRUE to exclude a product, FALSE to include it, $excluded to use the default behaviour.
    $cats = wp_get_post_terms( $product_id, 'product_cat', array( 'fields' => 'ids' ) );
    // Exclude products in category ID 21
    if ( in_array( 21, $cats ) ) {
        return TRUE;
    }
    // Exclude products in category ID 22
    if ( in_array( 22, $cats ) ) {
        return TRUE;
    }
    // Exclude products in category ID 23
    if ( in_array( 23, $cats ) ) {
        return TRUE;
    }
    // If not in the above categories use the default behaviour.
    return $excluded;
}
add_filter( 'woocommerce_gpf_exclude_product', 'lw_gpf_exclude_product', 11, 3);