Here's another "side effect" of the modern diet of processed foods: More people than ever are now experiencing the pain and misery of kidney stones.

That pain is so excruciating it's been described as the only thing comparable to the pain of childbirth -- and some women tell me kidney stones were actually the more painful of the two.

Yes, it's that bad. And now, new numbers show that 1 in 11 of us can expect to experience it, up from 1 in 20 just 16 years ago. Go back even earlier, and you'll find even fewer people had them.

Why? Easy answer: Diet. The more junk we eat, the more likely we'll get kidney stones.

We also get fatter, too, and UCLA researchers say their study confirms a link between obesity and kidney stones as well as both diabetes and gout and kidney stones.

But the study in European Urology really tells only part of the story. It's not that these conditions alone are causing all those kidney stones (although they certainly don't help). It's that the same modern diet of processed foods rich in saturated fats and refined carbohydrates are causing all of those things at once.

And that means eating better will slash your risk of obesity, diabetes, gout and kidney stones. It's like killing four birds with one (kidney) stone.

But if you're already fighting recurring battles with stones, you'll need to take more specific action -- and you can start with two nutrients: vitamin B6 and magnesium.

These nutrients work together to prevent the accumulation of calcium oxalate crystals in the kidneys. They're so effective that 500 mg of magnesium and 50 mg of B6 a day can reduce your risk of stones by 90 percent.

If that's not enough to do the trick for you, you may need to take even more drastic action -- and along with eating better and losing weight, you'll want to avoid:

Animal fats: Sorry, meat lovers -- animal fats and especially red meats can cause your body to excrete calcium. Before that calcium can leave the body, though, it has to pass through the kidneys -- where it can build up and form a stone.

Dairy: The calcium found in some of the most common dairy products -- especially milk, cheese and ice cream -- is not as easily absorbed as other dietary sources of calcium. And when it's not absorbed, it heads right for the kidneys.

Oxalic acid: You might think spinach, collards and celery are all healthy and for most people they are. But they also contain high levels of oxalic acid, and too much oxalic acid is a prime cause of kidney stones for those who are genetically susceptible.

Other sources of oxalic acid include some of the antioxidant-rich "superfoods" -- including blueberries, almonds, and cocoa. That means if you're suffering from frequent stones, all those delicious treats will have to be limited.

Sugar: High levels of sugar will suck the calcium right out of your bones and send it straight into your kidneys.

Soda: Along with extra sugar, many sodas -- even diet sodas -- contain phosphoric acid, which can also increase your risk of stones.

In addition, avoid alcohol, excess sodium, and caffeine as all three can dehydrate you -- and dehydration increases the concentration of minerals in the kidneys, which can then crystalize and form a stone.

It's not the easiest diet in the world since the restricted list is pretty long. But if you've ever battled kidney stones, you know the alternative is a lot of pain and misery.