How to evaluate a boolean variable in an if block in bash?

I have defined the following variable:

myVar=true

now I'd like to run something along the lines of this:

if [ myVar ]
then
    echo "true"
else
    echo "false"
fi

The above code does work, but if I try to set

myVar=false

it will still output true. What might be the problem?

edit: I know I can do something of the form

if [ "$myVar" = "true" ]; then ...

but it is kinda awkward.

Thanks