[blue_cristal (OP)]

Does processed food lose substantial nutritional qualities ( vitamins, etc ) ?

Are there significant amount of harmful substances added in the food processing ? If so, what are they ?

I already know that many types of processed food often contain an excessive quantity of saturated fats, sugar and salt, which are bad for your health.

But what about plain canned pre-cooked vegetables like bean sprouts, asparagus, spinach, olives, etc ?

[grumpy old mare]

Plain canned foods should not contain any additives other than what it says on the can (usually water, brine, sugar and/or salt), at least here in Europe. The nutritional value of 'plain' tinned or frozen food is said to hardly diminish at all through the process, that's why tinned fruit and veg also count for one's "5 a day".
(May be VERY different to tinned ready meals)

Otherwise - here's quite an interesting article:
http://lifeandhealth.guardian.co.uk/food/story/0,,1851546,00.html

As I used to type chemical "stuff", I avoid (for us humans and especially for our dogs!!) any processed foods and 'fizzy' drinks as I don't believe that some of the permitted additives really are 'safe' in the long run! That's even apart from the excessive use of salt, sugar and saturated fats in 'ready meals'/processed foods. Some colourings and other additives are now known to induce 'strange behaviour' in children (and in dogs).

The safety of a lot of containers (e.g. some baby bottles!) is also very much in question since the material used for the containers may 'pass on' some chemicals to the food/drink in the container.

[SquarishTriangle]

I hear processed fugu is somewhat 'healthier' than the alternative!

[Bored chemist]

It's perfectly possible for canned fruit and veg to have higher levels of vitamins than "fresh" produce. The "fresh" stuff has been lying around on the market shelf for a while and the vitamin content will have decreased over that time.
Much processed food contains a lot of fat, sugar and salt. Within reason, none of these re toxic- in fact they are normal. even vital, components of the diet.
The colourings flavours etc are added chemicals, but you should remember that the food is made from chemicals too. The aditives have been tested for safety- most of the other chemicals have not.Similarly the preservatives addded to food may not be entirely  devoid of toxicity - but you need to remember that some of the most toxic materials known are products of fungi and bacteria acting on food. The preservatives will usually be the lesser of two evils.

[Spam4 050822]

It depends what you talk about when you mention processed food.
If we're talking about goods that include ingredients like salt, sugar, artificial colors, flavorings, and preservatives, then that's not healthy. But it won't kill us in moderate amounts, either. I am all about balance. I won't shy away from what we call unhealthy foods but I won't eat them daily either.
If we're talking about canning, I don't consider that unhealthy. We even do it at home. Just read the ingredients to make sure that there are no extra ingredients added that shouldn't be there.

[paul cotter]

Nitrites are added to some meat products and these may be carcinogenic. However if you leave the nitrites out there is a substantial risk of botulism, a very serious form of food poisoning. As in most things in life it comes down to balancing risks.

[evan_au]

Is Processed Food Healthy ?

It depends entirely on what sort of processing you are talking about.

Some researchers gave volunteers goat steaks to chew on.
- raw, they were unable to extract much useful nutrition - they couldn't even break up the meat into pieces small enough to swallow
- I imagine that chewing on a whole goat would be even less effective!
- Ground-up meat is able to be digested more easily
- Cooked, they were able to chew the food quite effectively

So, cutting, grinding and cooking are ways to gain far more nutrition out of both meat and plant products.

Similarly, fermentation is able to extract nutrition from food sources where humans would not be so successful (think bread, beer, chocolate, kimchi, etc). It add flavours, preserves the food and discourages colonization by pathogenic bacteria.