I have been putting on weight．我开始发胖了。

putting on weight

例句：

1.I'm putting on weight daily, so he advised me to jog for half an hour every morning.

我的体重一天天地增加,因此他建议我每天早晨慢跑半小时.

2.It looks like I'm putting on a little weight.

我看起来好像胖了一点。