Growing up, it was indicated to me that fried foods were unhealthy - presumably, because of the increased fat content. Now, I don’t know much about nutrition, but I do know that a moderate amount of fat isn’t the end of the world - the question is, other than fat content, is there a significant difference between raw and fried foods? I’m especially wondering about already-fatty foods like hamburger, where there’s not actually any added fat - if I boiled or baked my burger, would there be any major difference?
Well, I do this thing where I fry up a bunch of potatoes. I use peanut oil, and I strain and reuse it.
So, I take an entire bottle of peanut oil and heat it up. Then I add maybe three pounds of potatoes, cut as french fries. The oil needs to be hot; the potatoes stay in it for maybe five minutes. I don’t put them all in at once, and when I take them out I drain them on paper towels, which absorb a lot of the oil.
Then I strain the oil and pour it back into the bottle. I usually strain it twice, once with a tea strainer and then again with another paper towel, which again absorbs quite a bit of oil.
The level of oil in the bottle has gone down about half an inch.
So, in any given fry, there is not that much oil. I figure it is about 1/4 cup for the whole 3 lbs, at the very most. This isn’t a scientific measurement by any means, just an estimate of what’s left after frying and the fact that a certain amount is absorbed by various paper towels in the process.
Of course, in the raw potatoes there isn’t any oil at all.
Depends. If you’re frying something thickly battered or not fast enough, yes, it will be greasy. But it’s possible to fry things without much oil sticking to it; frying quickly at high heat can help. Also, a moderate amount of a “good” oil such as olive oil indeed can be a part of a healthy diet.
There’s also probably a difference between frying in tallow versus frying in grapeseed oil.
On one episode of Good Eats, Alton Brown made fish and chips. I remember he said that there was only about two tablespoons of oil in the finished dish.
Two words: balanced diet.
Yep. The thing about fried food is, when done right, it’s not all that bad for you. When cooked at a proper temperature and for the right amount of time, the escaping steam prevents fat from entering the food. The problem is, if the oil isn’t at the right temp or the food is cooked too long, steam doesn’t escape and fat seeps in, making the food greasy (and obviously bad for you).
When people are talking about frying, they’re not really talking about what you do with a hamburger unless you drop your burgers into a vat of hot oil.
As a general rule, you have:
- Deep frying: food is totally submerged in oil
- Pan frying: food is partially submerged (at least 1/4 inch and often more) in oil
- Sauteing: food is cooked with just enough oil to cover the bottom of the pan
Grilling is sometimes used to refer to an open griddle, where you can’t cover the whole thing with fats so that things are mostly cooking on the metal surface (what you normally do with a burger), but grilling is also used to describe cooking at high temp directly over an open flame. (Which is what many people call BBQ, but if you have something sitting over flame, it’s not BBQ. Don’t get me started.)
A lot of people think a saute is healthier because you’ve got less oil in the pan, but if only 2 tbsp of oil is absorbed, it doesn’t matter whether you added 2 tbsp or 2 gallons to the pot because you’re still eating the same amount. As others have said, the two keys to controlling oil absorption are temperature and coating. Temperature because steam in food prevents oil from entering the food; if cooking temps are too low, you don’t get enough steam. Overcooking can also result in too much oil being absorbed. (Hush puppies are a great way to learn how hot is hot enough). Coating is important because a very thick batter can easily turn into a sponge. Nothing pisses me off more than a perfectly good onion ruined by an inch of greasy, overcooked batter.
That said… boiling, steaming, roasting, broiling and braising are all cooking methods that involve no added oil. So they are somewhat “healthier” in that you can avoid that extra tbsp or two of oil. Since that translates to 120-240 calories, you can see how eating steamed fish might be a lot better for your diet than fried fish. I think eating fried fish is still less fat than a steamed burger, though.
There are three other ways frying might be considered unhealthy and they are due to the composition of the fats.
Saturated fats include coconut oil, palm oil, peanut oil, lard, tallow, hydrogenated oils and others. Unsaturated fats are considered better for cardiovascular health and include olive oil, fish oils, canola oil and others. This distinction is NOT one of calories, though - olive oil is still 120 calories, just like bacon grease or lard.
Trans fats are the result of chemical processing of fats - usually hydrogenated oils which are commonly used by restaurants for frying. Crisco and margarine are hydrogenated oils commonly found in home kitchens. Some new formulations of hydrogenated oils contain only trace amounts (but never 0… they just round down if they have less than 0.5g per serving). The chemistry behind it is pretty cool, but think of trans fats as a kink in the molecule that makes it not fit in your digestive enzymes properly. They’ve been linked to cancer.
Cholesterol is the third component and is found in most animal fats like lard and bacon grease. Obviously, it’s linked to heart disease. Plant oils contain no cholesterol. That said, it would take a heart attack to make me quit cooking with bacon grease.
Fat issues aside, deep fat frying generates more polycyclic aromatic hydrocarbons than any other cooking technique, especially relative to water based methods. Many of these are carcinogenic so ensure adequate ventilation whilst cooking.
Yes! We didn’t have to wait for the 10th post for someone to actually read the OP.
So how much of a concern is this? Any data?
Surprisingly there isn’t a vast wealth of research in this area, though Fried foods: a risk factor for laryngeal cancer? provides a good summary of the available research, and finds increased laryngeal cancer risk odds of 1.6, 3.1, 1.9 and 1.9, for fried meat, fish, eggs and potatoes, respectively. Human contact with polycyclic aromatic hydrocarbons (PAHs) is unavoidable in the environment, and the greatest exposure is through diet. They are present in certain types of uncooked food, in addition to those generated in cooking, especially at high heat or over flames. PAHs are of a significantly greater risk in the developing world, where much cooking still involves wood, charcoal or coal briquettes.
It was explained to me as a known fact that frying foods, especially for a long time, especially at a restaurant deep fryer that uses the same oil for a while, was very unhealthy due to said carcinogens. So despite the apparent lack of research, a lot of people have an opinion on this issue. I, of course, ask ‘at what dose?’ It’s easy to pick any substance, inject three pounds of it into a rat, and find that it results in cancer.
Most of the evidence thus far, in suitably expansive studies, suggests that ‘ordinary’ dietary intake of fried food is correlated with an increased risk of cancer. Whether the 1.6-3.1 fold increase is sufficient to dissuade you, or somewhat alter your personal diet, is a matter of choice. It should be noted that PAHs are generated in other forms of high temperature cooking such as baking or grilling, so their advantage isn’t significant. As stated, good ventilation limits environmental exposure. Boiling, poaching and steaming are relatively safer methods due to their lower temperature.
Specific concerns raised over high levels of acrylamide in certain fried and baked foods have not correlated with increased epidemiological risk.
ETA: Most of the PAHs present within the oil component are aerosolised within the smoke, accounting for the high incidence of lung cancer in populations exposed to this risk.
So it’s the breathing of smoking oil that’s particularly bad?
(As a side-note, I don’t consider statements like “three times more!” as having enough information to influence my judgement. Sure, the three-fold observed increase is great from a statistical confidence point of view [ie, you can’t dispute this, it’s true!], but obviously that says nothing of overall harm.)
Yes, the fumes present a significant risk (e.g. Mumford et al. 1995; Chiang et al. 1997; Chiang et al. 1999), though PAHs are also present in the food itself (White et al. 2008; .pdf).
Exposure to certain airborne PAHs is reduced by approximately 75% through the use of an extractor fan.
I’m not sure how you would like me to better describe the level of harm. PAHs and other cytotoxic chemicals produced during high temperature cooking are harmful, raising your likelihood of certain cancers by several multiples. Taking a typical example of the number of stir-fries cooked per month, lung cancer incidents increase 1.96, 1.73, and 2.24 times, for 15–29, 30 and ≥31 meals cooked respectively. The total number of years spent cooking also increases incidence of cancer compared to little to no stir-frying (Metayer et al. 2002).
I think what Alex is getting at is that without knowing the base risk for the cancers in question, ‘three times as likely’ isn’t enough to judge total risk. Are we talking .001% to .003%, or 10% to 30%? That’s a big difference, no?
Tentatively extrapolating the rate of PAH-induced lung cancer in terms of risk to an average US males, Alex_Dubinsky could reasonably expect to double his mortality risk from c. 55/100,000 to c. 110/100,000, assuming he adopted the practice of stir-frying his food. His chances of dying from laryngeal cancer would be elevated from c. 1.3/100,000 to c. 3.9/100,000 in the case of a high dietary intake of fried fish (again assuming US male).
So, your chance of that cancer is about one outa 100,000 thousand?
You could increase your chances of that cancer by hundred up to a thousand and you’d still be more likely to die of any typical thing that you associate with death like car accidents, heart attacks, strokes…
Increasing a lottery level risk by a factor of three? I aint giving up fried foods for that let me tell you.
Laryngeal cancer is just one of several cancers implicated. Since this particular carcinoma is rare anyway, the increase in absolute numerical terms is very small, whilst remaining statistically significant. On the other hand, multiplying your risk of lung cancer by several factors has a much greater effect due to its prevalence. An approximate probability of dying of lung cancer is 1 in 18 (c. 5.6%). Doubling this should be of concern for an individual and in dealing with the public health policy of an entire population.