as light as

[alpacinoutd]

Hello.

Imagine someone does a lot of exercise and they don't have body fat and they are light.

Now, you want to give them a compliment. Can you say "as light as a bird"? Or as light as a feather?

Do these work?

1. Emily works out every day. She is as light as a bird.

2. Emily works out every day. She is as light as a feather.

Is there another idiom or more interesting way of expressing that idea?

[emsr2d2]

Of the two, only "light as a feather" works. There are some really heavy birds!

However, it's not a very natural way of describing someone's weight (not something we do very often anyway). I find it particularly odd when connected to the idea that she works out. Generally, working out develops your muscles which, counter-intuitively, can actually weigh more than fat, so it's not necessarily true that someone who works out every day is going to weigh less than someone who doesn't.

I'd say something like "There's not an ounce of fat on her".

[alpacinoutd]

Of the two, only "light as a feather" works. There are some really heavy birds!

However, it's not a very natural way of describing someone's weight (not something we do very often anyway). I find it particularly odd when connected to the idea that she works out. Generally, working out develops your muscles which, counter-intuitively, can actually weigh more than fat, so it's not necessarily true that someone who works out every day is going to weigh less than someone who doesn't.

I'd say something like "There's not an ounce of fat on her".

Regardless of the working out part, is there an idiom which can be used to highlight the fact that she is "light"?

[emsr2d2]

As a standalone sentence, "She is/She looks as light as a feather" is OK. You might hear "She looks like she'd be blown over by a strong breeze" in BrE. If referring to her build rather than her actual weight, you can use "She's as thin/skinny as a rake" in BrE.

[Tarheel]

"As thin as a rail" in American English.