use HTML::Parser;
my $parser = HTML::Parser->new(
    start_h => [ \&_starttag, 'self, tagname, attr' ],
    end_h   => [ \&_endtag,   'self, tagname' ],
    text_h  => [ \&_text,     'self, dtext' ]
  );

$parser->parse($email_text);

sub _starttag {
    my ($self, $tag, $attr) = @_;
    $self->{'_body'} = 1 if($tag eq 'body');
}

sub _endtag {
    my ($self, $tag) = @_;
    $self->{'_body' } = 0 if($tag eq 'body'  );
}

sub _text {
    my ($self, $dtext) = @_;

    $dtext =~ s/\A\s+//;
    $dtext =~ s/\s+\z//;
    return() unless ( length($dtext) > 0 and $dtext =~ /[^\s]/ );

    if ($self->{'_body'}    == 1) {
      print $dtext;
    }
}