healthy的比较级是more healthy 还是healthies

healthier，另外还有heavier earlier happier lazier curlier 等等
（以y结尾的双音节形容词都是y变i加er或est变成比较级或最高级）

He looks healthier in contrast to his former self.
他与以前相比，显得更健康些。
-- 英汉 - 辞典例句
Lean meat is healthier for you than fatty meat.
对你来说,瘦肉比肥肉更有利于健康。
-- 英汉 - 辞典例句
We could supposedly emerge as a smaller but healthier company.
我们可以作为一个规模较小但较为健康的公司而东山再起。

A new program has been launched to provide children in developing countries with more healthy foods.
一项专为发展中国家的儿童提供更健康的食物的新计划已开始启动。
-- 交互式慢速英语-夏季号 - Child Nutrition Program
Efforts are under way to modify other fatty acids to make oils more healthy for consumers.
还有人正努力改造其他脂肪酸，为消费者制造更健康的油品。
"They hoped the government could create a more healthy environment for children," said deputy minister Zhao Shi.
“很多父母都希望政府能为孩子的成长创造一个更健康的环境，”赵室表示。
-- 汉英 - 翻译参考

都可以啊。more healthy or healthier。