He must have a hollow leg because he can eat so much and never seems full.
У него, должно быть, бездонный желудок, потому что он может съесть так много и никогда не выглядит сытым.
Definitions
A 'hollow leg' is an informal phrase used to describe someone who can eat or drink a large amount without seeming to get full or drunk. It is often used humorously to refer to a person with a big appetite or high tolerance for alcohol.
