Why is frying unhealthy?

[=control freak=]

Is it only unhealthy if you are using an unhealthy oil to fry food in, or is all frying unhealthy? If so, why?

[Baichi]

Because the plane might crash.

[Gary]

Heating oils can change it's characteristics, so what starts as a healthy oil can end up as an unhealthy one.

[Moi]

Isn't there a theory/fact about carbonising food as well?
Anything browned = bad?

[Burnsey]

Isn't there a theory/fact about carbonising food as well?
Anything browned = bad?

I heard something about this too, something to do with the generation of carcinogenic substances in meat when it is burnt, although I'm not sure to what extent they are formed when something is brown as opposed to black (a la My Dad's BBQ).

I also read from what seemed to be a reasnobly reliant source for science (i.e not a newspaper) that frying seems to affect the ease at which carcinogenic nitrites present as preservatives in stuff like bacon are absorbed into the body.

So to conclude - grill.

[Baichi]

Anything browned = bad?




True for underwear at least.

[Yohan]

Additionally, if you are talking about deep frying, what you are doing generally is putting some sort of wet stuff on a peice of meat (usually oil, or egg), then coating it with some kind of simple carb (bread crumbs, corn flakes) and then submerging it in boiling oil (generally peanut) so that the oil soaks into the simple carb and is heated. Thus the fat profile has changed. So it's not so much UNHEALTHY as it is, very nutritionally dense and has a poor fat profile, and will cause an insulin spike/crash, making you hungry fast. So it makes you fat if you eat it all the time.

I think most all foods can go in your diet. You could probably get away with having some kind of high density food like that after a moderate to heavy workout, and it would have a big chunk of protein in the middle.

[flaming]

I poach my eggs in butter. :cool:

[Garrett]

Is it only unhealthy if you are using an unhealthy oil to fry food in, or is all frying unhealthy? If so, why?

Are you talking just frying in a pan or deep frying?

Frying in a pan - perfectly healthy using the right oils. Canola/Olive and other mono/poly oils are quite good. The temperatures reached during fry pan cooking are not high enough to change the fat content to any large degree.

Deep frying - Depends on the type of oil being used and how long it has been there. The temperature does get hot enough to change the fat profile, but this is only after repeated uses of the same batch of oil. If fresh oil is used each time it shouldn't be a problem. Again the type of oil is important, mono/poly oils are the better choices, but have a lower flash point, so care needs to be taken about how hot the deep fryer is. The unsaturated fats also change fat profiles quicker during deep frying, so need to be changed more often.

As was said above, the main 'problem ' about deep frying is the energy density of the food you then eat.

[=control freak=]

Heating oils can change it's characteristics, so what starts as a healthy oil can end up as an unhealthy one.

Can you elaborate? eg Which oils? Rough temparatures?

[Prons]

So frying is bad, but BBQing not bad?

[=control freak=]

Additionally, if you are talking about deep frying, what you are doing generally is putting some sort of wet stuff on a peice of meat (usually oil, or egg), then coating it with some kind of simple carb (bread crumbs, corn flakes) and then submerging it in boiling oil (generally peanut) so that the oil soaks into the simple carb and is heated. Thus the fat profile has changed. So it's not so much UNHEALTHY as it is, very nutritionally dense and has a poor fat profile, and will cause an insulin spike/crash, making you hungry fast. So it makes you fat if you eat it all the time.

I think most all foods can go in your diet. You could probably get away with having some kind of high density food like that after a moderate to heavy workout, and it would have a big chunk of protein in the middle.

What do you mean by Nutritionally dense? Do you mean because there's so many different foods it is harder to digest?

What do you mean by the 'fat profile' in this case?

Can you explain why it would cause an insulin spike/crash? Again I could guess why you mean this, but I'm not certain.......



Thanks!

[=control freak=]

Are you talking just frying in a pan or deep frying?

Frying in a pan - perfectly healthy using the right oils. Canola/Olive and other mono/poly oils are quite good. The temperatures reached during fry pan cooking are not high enough to change the fat content to any large degree.

Deep frying - Depends on the type of oil being used and how long it has been there. The temperature does get hot enough to change the fat profile, but this is only after repeated uses of the same batch of oil. If fresh oil is used each time it shouldn't be a problem. Again the type of oil is important, mono/poly oils are the better choices, but have a lower flash point, so care needs to be taken about how hot the deep fryer is. The unsaturated fats also change fat profiles quicker during deep frying, so need to be changed more often.

As was said above, the main 'problem ' about deep frying is the energy density of the food you then eat.

Frying in a pan. I take it you would disagree that toasted(so to speak) food is not a concern then?



Thanks

[CosmicFish]

Can you elaborate? eg Which oils? Rough temparatures?
Here's a list of the smoke points of various oils:

http://www.goodeatsfanpage.com/CollectedInfo/OilSmokePoints.htm

Obviously, the lower the smoke point, the more prone it is to being changed into an unhealthy fat.

[Moi]

Frying in a pan. I take it you would disagree that toasted(so to speak) food is not a concern then?


The theory is if you change a foods colour or burns whilst cooking it you are making it more carsonagenic. Where do you stop with food? Everythings bad for you.

http://www.blurtit.com/q378124.html

http://news.bbc.co.uk/1/hi/health/7124501.stm

[Yohan]

What do you mean by Nutritionally dense? Do you mean because there's so many different foods it is harder to digest?

What do you mean by the 'fat profile' in this case?

Can you explain why it would cause an insulin spike/crash? Again I could guess why you mean this, but I'm not certain.......

Nutritionally dense means it has a lot of energy packed into a very small volume. Hence why you get almost a comparable amount of calories from the breading as you do from the meat.

As far as the fat profile thing, I had to do some reading to get to the heart of that and I'm still not entirely clear.

One source says:

Oil, when it’s overheated, literally deteriorates chemically. The rate of the breakdown (and total formation of toxic compounds) is dependent on the type of oil and temperature. Initially, the oil’s decomposition results in the creation of hydroperoxids and then increasing levels of aldehydes. (Aldehydes are toxic compounds and recognized “markers of oxidative stress in cells” and are known contributors to “degenerative illnesses.” . . . But here are the basics. If an oil is mostly saturated, it’s pretty stable. If it’s mostly mono-saturated, it’s pretty stable. If it’s polyunsaturated, it’s anybody’s game. More seriously, oils that contain mostly polyunsaturated fats will generally be less stable, but there’s significant variation. We’ll get to the full picture in a minute.

Another source: Processes of oxidative degradation

Researchers investigated processes of oxidative degradation - notably that caused at 70ºC with ventilation - of a broad group of oils with very wide-ranging compositions. Another degradation process studied was that which is caused by microwave action that does not heat greater than a temperature of 190 ºC.

In both processes deterioration of the oils takes place. In the first type of process (70 ºC with ventilation) hydroperoxides are first produced and subsequently aldehydes. In the second kind of process (microwave) it is basically aldehydes produced. It has to be pointed out that both the oxidative conditions and the composition of the oil determined the velocity of the degradation and both the nature and concentration of the compounds produced.

These studies have shown, for the first time, that degradation of lipids in foods can produce toxic oxygenated aldehydes. These compounds, well-known in medical studies for their geno- and cytotoxic activity, considered as markers of oxidative stress in cells as well as being causal agents of degenerative illnesses, had not previously been detected in foodstuffs.

Researchers have shown that some oils produce these toxic substances in greater quantities and at a greater rate. Virgin olive oil was, amongst all the oils studied, that which took longer to produce this type of compounds and produced a lower concentration of them.

Got no cited articles but both sources seem to agree.

Insulin is the hormone that takes up glucose . . . now that I think about it, I'm not so sure it would cause an insulin spike - I'm not sure if the breading would get processed into glucose or not.

[=control freak=]

Thanks everyone. This may sound like a stupid question, but how exactly do you know when your oil is at smoke point. Would you say it is when you can actually visually observe smoke, or when you smell the oil, or both at the same time, or something else?

[Yohan]

Thanks everyone. This may sound like a stupid question, but how exactly do you know when your oil is at smoke point. Would you say it is when you can actually visually observe smoke, or when you smell the oil, or both at the same time, or something else?

You can see and smell it. When cooking in a frying pan, i only use 1 tsb oil for every serving of protein.

[=control freak=]

Surely using less oil will make the food and oil more likely to burn more quickly?

[Yohan]

When you go to cook whatever you are cooking, you just put the oil in, give it a second to warm up, then plop whatever you are cooking down in the oil. That way the meat soaks it up and won't stick till it starts cooking out some of the juices.

[Yohan]

And yes, there is a higher risk of burning the food, but a T of olive oil contains about 120 calories - so you might add as much as 120 calories to a meal if you cook your meat in 1 T of olive oil.

[wrydolphin]

It also depends upon the type of pan. I like cast iron and a well used, well seasoned cast iron pan is pretty much the best non-stick surface you can find. Most iron woks can do the same so you add much less oil to the cooking.