The news that leptin made fat mice thin in a matter of weeks had a massive popular appeal.瘦蛋白让胖老鼠在几周内瘦下来的新闻在广大人群中引起了轰动

a matter of: 大约

The revolt was suppressed in a matter of hours.

叛乱在几小时之内就镇压下去了。

It's a matter of a few more miles, that's all.

最多再有几英里，也不过如此。

The hypothalamus acts like a thermostat.下丘脑像自动恒温器一样工作

act like:举止像 ...

She was stupid in the extreme to act like that.

她那样做真是愚蠢极了。

I don't want to act like my friend.

我不想像我朋友那样干。

either by gaining weight or losing weight, is actively resisted.无论是体重增加或是体重减少，都可以得到有效地抑制

gain weight:增加体重

People tend to gain weight on holidays.

人们常常在假期长胖。

lose weight:减肥

His abstemious habit helps him to lose weight.

他那有节制的饮食习惯有助于他减肥。