I've lost a few pounds.

I lost a few pounds.

I've lost some weight.

- You look good. Did you lose some weight? / Ты изменился. Ты похудел?

- Yep, I lost a few pounds. / Да, я немного похудел.

I've lost some weight.

I lost 17 kilos.

я похудел на четыре килограмма перевод на английский

I lost ten pounds.

- You look so different! / Ты по-другому выглядишь. 

- I lost ten pounds. / Я похудел на три килограмма.