If no torque is applied, there will be no change in the KE of the body. Just as there will be no increase in the KE of a non-rotating body if no force is pulling (or pushing) on it. The only thing happening is that rotating motion of all the parts of the body gets closer to the axis of rotation. For example, the outermost parts, having the highest velocity, take their velocity with them when the body contracts, so they travel the same distance per unit of time, but on a smaller circle, which means that their angular velocity (so not their instantaneous linear velocity) increases. They travel the same distance but need more turns to do so. This holds for all particles. So it is the angular velocity only that changes and not the KE present in the rotation.
The forces that pull the particles of the body inwards (or outwards) are perpendicular to the angular velocities so they cannot make them move faster (or slower).