pack on

Verb

informal transitive

(transitive, informal) To add (fat, muscle, etc.) so as to increase mass or bulk.

Japanese Meaning

（脂肪や筋肉などを）つけて、体のマスやボリュームを増やす、つまり大きくすること

He started to pack on muscle after switching to a high-protein diet and lifting weights regularly.

彼は高タンパクの食事に切り替え、定期的に筋力トレーニングを行うようになってから筋肉をつけ始めた。

Sense（1）

(transitive, informal) To add (fat, muscle, etc.) so as to increase mass or bulk.

Most strength coaches agree that to gain an inch on your arms, you have to pack on at least 10 pounds of body mass.

packs on

（ present singular third-person ）

packing on

（ participle present ）

packed on

（ participle past ）

packed on

（ past ）