How to Display CPT Posts on index Page

Add a function hooked to pre_get_posts which modifies post_type argument of the main query to add your custom post type.

function wpd_home_post_types( $query ){
    if( $query->is_home() && $query->is_main_query() ){
        $query->set( 'post_type', array( 'post', 'natural_food' ) );
    }
}
add_action( 'pre_get_posts', 'wpd_home_post_types' );