The best defense is...malnourishment?

Generally speaking, in order to increase stopping power from a bullet, you increase the trauma that it creates.

Hollow points accomplish this by expanding on target to create a larger wound channel.

There are some problems with this. Hollow points are prohibited under the Hague Conventions that NATO ascribes to (even though they are the most frequent type of bullets used by civilian agencies). Another problem is that you reduce the penetrative power of the bullet, which is fine inside a warm body because it means that the kinetic energy is being dissipated into the surrounding flesh but not so good against kevlar.

Full-metal jacket military rounds are designed instead to yaw at very specific velocity and resistance profiles. Ideally you would be able to penetrate a vest and then it would tumble and fragment inside the target's mass to increase stopping power.

With this background, let me get to my funny anecdote: NATO forces have discovered that enemy combatants in Afghanistan often have too little muscle mass to initiate yawing, contributing to reports of poor stopping power.

Sometimes hot-knife-through-butter isn't the preferred approach.