What are those things that pro tennis players eat before they play? It is squeezed into the mouth from packet?

Question

What are those things that pro tennis players eat before they play? It is squeezed into the mouth from packet?

Answer 1

It is probably an energy-gel packet which contains carbohydrates to keep up their energy level

Answer 2

They are food supplement packs. They contain glucose or fructose to provide a sugar rush. It is much the same as drinking lucozade. I found out that you can buy them online. You have to buy a box full and they are not cheap! Stick with powerade or something like that unless you can afford it.

Answer 3

energy and carbohydrates  giving food i think,,like chocolates...