If the equilibrium moves to the left then more reactants will be produced as we write a chemical equation going from
(LHS) Reactants to Products (RHS)
And so reactants are on the left hand side.
If the equilibrium shifts to the left, then it favours the reaction going from products to reactants.
Therefore more reactants will be produced.
It has to produce more reactants in order to oppose the change imposed onto the system.
This change in this case where the equilibrium shifts to the left, could be an increase in temperature for an exothermic reaction for example.