Dr-Cheeser is making a joke.

The term 'soy' refers to soy based food products. Soy contains estrogen and consuming too much soy can lead to males developing female characteristics such as low muscle tone, effeminate facial features, and gynecomastia (Man Boobs).

'Soylent' is a reference to 'Soylent Green' which is a book describing a dystopian future where the world is over populated but everyone eats a substance called 'soylent green'. Turns out soylent green is made from the dead bodies of people.

There is a food substitute called 'soylent' which is named after Soylent Green. Dr-Cheeser is making reference to this drink.