1,eat balanced diet不搭配.“吃掉均衡饮食”听起来也别扭吧.
2,想表达饮食均衡,单用词组“balanced diet”就可以了.
3,表达保持健康可以用“keep you healthy”（keep somebody + adj.) 或者“keep your health”(keep + n.)
4,表达中文“均衡的饮食可以保持健康”
可用：Balanced diet can keep you healthy.
或者：Balanced diet can keep your health.