Children expend a lot of energy and may need more high-energy food than adults.

孩子们耗能多，可能比成人需要更多高能量的食物。

In fact, health experts have expended a great deal of effort in their search for an acceptable definition.

实际上，健康专家们已经在研究中付出了很多努力，来寻找一个普遍接受的定义。