Soup is good food? Not if it comes from a can!

I'm sure you already know all about the preservatives, artificial flavors, and just plain low-quality ingredients that fill each can of soup. But believe it or not, that's not even the worst of it.

Soup cans -- as well as the cans of other foods -- are lined with an estrogen-like chemical called bisphenol A (BPA) to help prevent rust and keep your canned goods from having too much of that metallic taste.

But this chemical doesn't just sit there in the can lining -- it breaks free and leeches out into the soup. And that means you're getting a secret burst of hormones with every spoonful.

Now there's something you don't see advertised on the label.

The latest research finds that all it takes is a can a day for five straight days to give yourself a dramatic surge in BPA levels. So if you're the type who likes to nuke some soup for lunch, you might want to pick a new habit.

Researchers from the Harvard School of Public Health divided 75 volunteers into two groups: One ate a 12-ounce serving of vegetarian canned soup every day for five days... while the others ate freshly made vegetable soup.

After a two-day "washout" period, the two groups switched places.

In both cases, urine tests found an average increase in BPA levels of 1,221 percent after five days of canned soup. The researchers say they suspect those levels might be temporary -- but temporary or not, do you really want all those extra hormones surging through your body?

Of course you don't -- because despite chemical industry claims to the contrary, BPA is unsafe for human consumption.

It's already been linked to diabetes, heart disease and sexual dysfunction in adults -- while in kids, it's been linked to early puberty and behavioral problems. And that's only what we know so far. It seems like every few weeks, another study finds yet another way this chemical can wreck your body.

None of this should scare you away from soups and stews, which are perfect winter meals. Just learn to make them yourself -- you might be surprised at how easy it is.

One recent study found that making the switch to freshly made foods -- and ditching anything stored in BPA-lined cans and containers -- slashed BPA levels by 60 percent in just three days.

Find out how to get started here.