Question

He
(lose weight) if he had stopped eating so
much.
*
O will lose weight
O would lose weight
O would have lost weight
O lost weight​

Answer 1

Answer:

He would have lost weight if he had stopped eating so much.

(though the question is rather offensive)

Answer 2

Answer:

He would have lost weight if he had stopped eating so much.

Explanation:

As the sentence is given in past tense we have to answer it in the same tense: He (lose weight) if he had stopped eating so much.

So our answer would be: He would have lost weight if he had stopped eating so much.