Kidney stones fit all three of those categories.
But the worst part about these nasty growths is how common they are.
Research shows that 12% of Americans will develop stones, and once they form in your body they're likely to come back again.
Thankfully, we know a lot about how these stones are made, and how to make them stop.
Here are the 9 most important pieces of advice from doctors to prevent kidney stones:
1. Eat less meat
Specifically meats that raise the amount of uric acid in your urine.
This acid promotes a common kind of kidney stone, and mainly comes from the meat in our diet.
While chicken and fish contain uric acid, the worst offenders are shellfish, red meat, and organ meat (liver, tripe).
Avoid excessive drinking for the same reason - alcohol is rich in uric acid.
2. Cut salt from your diet
One of the most common kinds of kidney stones is caused by calcium crystals.
A lot of salt in your urine prevents your body from absorbing calcium, which helps the stones to grow.
Mainly, you should be avoiding processed foods, canned soups and meals, and lunch meats.
3. Enjoy more citrus fruit
These colorful fruits are full of citrate, or citric acid.
Unlike other acids, citrate helps break down stones in your kidneys before they form.
Oranges, grapefruits, and lemonade are all good sources of citrate (just choose sugar-free lemonade).
4. Drink more water (really)
We know, we know, you're tired of hearing you should drink more water.
But when it comes to kidney stones, this is really important.
Normally, our urine dissolves kidney stones.
But when we don't drink enough water, the low concentration of urine encourages them to grow.
Don't forget: if you're exercising regularly, you need to drink even more water than you normally would.