use Data::Dumper;

my $data1 = [
        { "shape" => "round", "food" => "apple" },
        { "shape" => "square", "food" => "pear" },
        { "shape" => "oval", "food" => "grape" },
];

my $data2 = [
        { "big" => "cow", "small" => "bunny" },
        { "big" => "horse", "small" => "mouse" },
];

foreach (0..2) {
        my $d = $data1->[$_];
        $d->{sizes} = $data2;
        print Dumper($d);
}