Cats are intelligent hunters who love to work for their food. But many kitties who live indoors with their human companions have few opportunities to engage in such natural hunting and foraging behaviors. This lack of mental stimulation can lead to boredom, obesity, and even aggression. But letting cats outside puts them at grave risk of contracting an illness or being injured, while bird populations will suffer from over-predation. So what’s a responsible cat guardian to do?

That’s easy! A new scholarly review has found that food puzzles— devices that release food only when an animal interacts with them—can help decrease an indoor cat’s boredom by stimulating her both mentally and physically while still keeping her safely indoors.

Cats are happier and healthier when their minds and bodies are active, and these puzzles tap into a cat’s natural instinct to hunt and forage. According to the veterinarians who published the review, one obese cat who started using food puzzles lost 20 percent of his bodyweight in just one year, while another cat’s frustration-based aggression against his guardian completely dissipated after having food puzzles for six months.

Rather than being handed food, kitties have to work for their meal by batting food pieces out of cups, mazes, toys, or other designs, or they may have to push around a cylinder with their nose until food falls out of it. There are countless options available to buy, or you can make puzzles yourself at home—it could be as simple as cutting a few paw-sized holes in a shoe box and then sprinkling some dry food inside.

But, like us, cats can lose interest in toys they’ve figured out, so think about getting a few food puzzles that you can then rotate out when kitty starts to get bored. Also, keep in mind that each cat is different, so a toy one cat likes might not appeal at all to another. If your cat shows no interest in his new puzzle, it might be because the game’s not his particular cup of tea. Try different styles of puzzles until you find one that’s just your cat’s speed—and you’ll both be happier for it!

How do you enrich your indoor kitty’s life? Have you built any enrichment tools yourself? Tell us in the comments below!