Deep frying is a common cooking method used across the globe.
Popular fried foods include: fish, french fries, chicken strips and cheese sticks,
Fried foods tend to be high in calories and trans fat.
Fried Foods Are High in Calories
Fried foods are typically coated in batter or flour prior to frying.
When foods are fried in oil, they lose water and absorb fat, which further increases their calorie content.
Fried foods, in general, are significantly higher in fat and calories than their non-fried counterparts: one small baked potato (100 grams) contains 93 calories and 0 grams of fat, while the same amount (100 grams) of french fries contain 319 calories and 17 grams of fat.
Fried Foods typically are high in trans fats.
Trans fats are formed when unsaturated fats undergo hydrogenation.
Food manufacturers often hydrogenate fats using high pressure and hydrogen gas to increase their shelf life and stability.
Hydrogenation also occurs when oils are heated to very high temperatures during cooking.
Hydrogenation process changes the chemical structure of fats, making them difficult to break down, which can ultimately lead to negative health effects.
Trans fats are associated with an increased risk of many diseases, including heart disease, cancer, diabetes and obesity.
Fried foods are cooked in oil at extremely high temperatures, and are likely to contain trans fats.
Fried foods are often cooked in processed vegetable or seed oils, which may contain trans fats prior to heating.
A study of soybean and canola oils found that 0.6–4.2% of their fatty acid contents were trans fats, and when these oils are heated to high temperatures, such as during frying, their trans fat content can increase.
Each time an oil is re-used for frying, its trans fat content increases.
Trans fats that occur naturally in foods like meat and dairy products have not been shown to have the same negative effects on health as those found in fried and processed foods.
Large observational studies found that the more often people ate fried foods, the greater their risk of developing heart disease.
One study found that women eating one or more servings of fried fish per week had a 48% higher risk of heart failure, compared to those who consumed 1–3 servings per month: increased baked or broiled fish intake was associated with a lower risk.
An observational study found that a diet high in fried foods was associated with a significantly higher risk of heart attack.
Several studies have found that eating fried foods puts you at a higher risk of developing type 2 diabetes.
A study found that people who ate fast food more than two times per week were twice as likely to develop insulin resistance, compared to those who ate it less than once a week.
Two large observational studies found a strong association between how often participants ate fried food and the risk of type 2 diabetes.
Those consuming 4–6 servings of fried food per week were 39% more likely to develop type 2 diabetes, compared to those consuming less than one serving per week.
Similarly, those who ate fried food seven or more times per week were 55% more likely to develop type 2 diabetes, compared to those consuming less than one serving per week.
Fried foods contain more calories than their non-fried counterparts, so eating a lot of them can significantly increase the calorie intake.
Trans fats in fried foods may play a significant role in weight gain, affecting the hormones that regulate appetite and fat storage.
Trans fat consumption significantly increases belly fat.
An observational study that reviewed the diets of 41,518 women over eight years found that increasing trans fat intake by 1% resulted in a weight gain of 1.2 pounds in normal-weight women.
Among women who were overweight, a 1% increase in trans fat intake resulted in a weight gain of 2.3 pounds over the course of the study.
Increases in monounsaturated and polyunsaturated fat intakes were not associated with weight gain.
Fried food in multiple observational studies have shown a positive association between its intake and obesity.
Acrylamide is a toxic substance that can form in foods during high-temperature cooking, such as frying, roasting or baking.
It is formed by a chemical reaction between sugars and an amino acid called asparagine.
Starchy foods like fried potato products and baked goods typically have higher concentrations of acrylamide.
While a handful of human studies have investigated acrylamide intake, the evidence is mixed.
One review found a modest association between dietary acrylamide in humans and kidney, endometrial and ovarian cancers.
Other studies found that dietary acrylamide in humans is not related to the risk of any type of common cancer.
The type of oil used for frying greatly influences the health risks associated with fried foods.
Oils that can withstand much higher temperatures than others, are safer to use.
Generally speaking, oils that consist mostly of saturated and monounsaturated fats are the most stable when heated.
Coconut oil, olive oil and avocado oil are among the healthiest.
Coconut oil:
Over 90% of the fatty acids in coconut oil is saturated, which makes it very resistant to heat.
Even after eight hours of continuous deep frying, its quality does not deteriorate.
Olive oil contains mostly monounsaturated fats, making it relatively stable for high-temperature cooking.
Olive oil can be used in a deep fryer for up to 24 hours before a significant amount of oxidation begins to occur.
The composition of avocado oil is similar to that of olive oil.
Avocado oil also has an extremely high heat tolerance, making it a good choice for deep frying.
Cooking oils that contain a high amount of polyunsaturated fats are far less stable and known to form acrylamide when exposed to high heat, and include:
Canola oil
Soybean oil
Cottonseed oil
Corn oil
Sesame oil
Sunflower oil
Safflower oil
Grape seed oil
Rice bran oil
These oils are processed, and up to 4% of their fatty acid content is trans fats prior to frying.
Polyunsaturated fats contain two or more double bonds in their chemical structure.
Double bonds can react with oxygen and form harmful compounds when exposed to high heat.
Alternative cooking methods, including:
Oven-frying: This method involves baking foods at a very high temperature (450°F or 232°C), which allows foods to get crispy using little or no oil.
Air-frying: circulate extremely hot air around food, ending up crispy on the outside and very moist on the inside, similar to traditionally fried foods, but using 70–80% less oil.
Coconut oil, olive oil and avocado oil are among the healthiest oils to fry foods in.
Deep frying involves cooking food by submerging it in hot oil, with the ideal temperature is around 350–375°F (176–190°C).
Submerging a food in oil at this temperature causes its surface to cook almost instantly.
As it cooks, it forms a type of seal that the oil cannot penetrate.
The moisture inside the food turns into steam, cooking the food from the inside.
The steam also helps keep the oil out of the food.
However, you have to have the right temperature:
If the temperature is too low the oil will seep into the food, making it greasy, and If too high and it can dry out the food and oxidize the oil
Health oils have a high smoke point,
are stable, so they don’t react with oxygen when heated.
Oils that contain higher levels of saturated fats tend to be more stable when heated.
Oils that are mostly saturated and monounsaturated are good for frying.
Cooking oils that contain large amounts of polyunsaturated fats are less suitable for frying .
Butter is unsuitable for deep frying, as it contains small amounts of carbs and protein that burn when heated.
Animal fats consist mainly of saturated and monounsaturated fats, making them suitable for cooking at high temperatures.
((Olive oil)) is one of the healthiest fats.
Olive oil is resistant to heat because it’s high in monounsaturated fatty acids.
The flavor and fragrance of olive oil may deteriorate when heated for a long time.
Avocado oil has a similar composition to olive oil. It’s mainly monounsaturated with some saturated and polyunsaturated fats mixed in.
Peanut oil has a high smoke point of about 446°F (230°C), contains around 32% polyunsaturated fats, making it vulnerable to oxidative damage at high temperatures.
Palm oil consists mostly of saturated and monounsaturated fats.
Vegetable oils that are high in polyunsaturated fatty acids, such as:
soybean oil
corn oil
canola oil
cottonseed oil
safflower oil
rice bran oil
grapeseed oil
sunflower oil
sesame oil
Using these oils for deep frying can result in large amounts of oxidized fatty acids and harmful compounds.
Vegetable oils that are high in polyunsaturated fatty acids are unsuitable for deep frying.
They are less heat-resistant than oils or fats that are high in saturated or monounsaturated fatty acids.
Phenols are naturally occurring antioxidants unique to many vegetables, that contribute to the vegetables’ flavor and can be supportive of good health.
Foods sautéed in olive oil had phenols that are not present in the raw form, as they picked up phenols from the olive oil in deep-frying and sautéing, and thus the antioxidant capacity of the foods increased when they were prepared in oil.
Frying is a method where the vegetable is cooked by submerging it in oil.
Frying can take longer, allowing the food to absorb more fat.
Deep-frying often has a higher cooking temperature, which is not good with extra virgin olive oil, as this oil has a low smoke point.
Sautéing means cooking in a small amount of oil, and also usually implies cooking quickly, resulting in a lightly cooked food.
Steaming and boiling vegetables help to soften and break them down, making their nutrients easier to digest than when they are raw.
Some vegetables, like carrots, zucchini, and broccoli when fried caused them to retain less nutrients and antioxidants than boiling or steaming.
Over 90% of the fatty acids in coconut oil are saturated, which makes it very resistant to heat.
Coconut oil is semi-solid at room temperature and it can last for months and years without going rancid.
Coconut oil also has powerful health benefits.
It is particularly rich in a fatty acid called Lauric Acid, which can improve cholesterol and help kill bacteria and other pathogens.
Coconut oil fats can also boost metabolism slightly and increase feelings of fullness compared to other fats.
Coconut oil fatty Acid Breakdown:
Saturated: 92%.
Monounsaturated: 6%.
Polyunsaturated: 1.6%.
The saturated fats used to be considered unhealthy, but new studies prove that they are totally harmless.
Saturated fats are a safe source of energy for humans.
Butter was also demonized in the past due to its saturated fat content.
Butter contains Vitamins A, E and K2, and also rich in the fatty acids Conjugated Linoleic Acid (CLA) and Butyrate, both of which have powerful health benefits.
Conjugated Linoleic Acid may lower body fat percentage in humans and butyrate can fight inflammation, improve gut health and has been shown to make rats completely resistant to becoming obese.
Fatty Acid Breakdown of buter:
Saturated: 68%.
Monounsaturated: 28%.
Polyunsaturated: 4%.
Butter does contain tiny amounts of sugars and proteins and tends to get burned during high heat cooking like frying.
The fatty acid content of animals tends to vary depending on what the animals eat.
If they eat a lot of grains, the fats will contain quite a bit of polyunsaturated fats.
If the animals are pastured raised or grass-fed, there will be more saturated and monounsaturated fats in them.
Therefore, animal fats from animals that are naturally raised are excellent options for cooking.
The relative degree of saturation of the fatty acids is the most important factor in determining an oil’s resistance to oxidation and rancidification, both at high and low heat.
Saturated fats have only single bonds in the fatty acid molecules, monounsaturated fats have one double bond and polyunsaturated fats have two or more.
It is these double bonds that are chemically reactive and sensitive to heat.
Saturated fats and monounsaturated fats are pretty resistant to heating, but oils that are high in polyunsaturated fats should be avoided for cooking .
Palm oil is derived from the fruit of oil palms.
It consists mostly of saturated and monounsaturated fats, with small amounts of polyunsaturates.
This makes palm oil a good choice for cooking.
Red Palm Oil, unrefined, is best for cooking, and rich in Vitamins E, Coenzyme Q10 and other nutrients.
Avocado oil is primarily monounsaturated, with some saturated and polyunsaturated mixed in.
Fish oil is very rich in the animal form of Omega-3 fatty acids, which are DHA and EPA.
A tablespoon of fish oil can satisfy daily needs for these fatty acids.
The best fish oil is cod fish liver oil.
Due to its high concentration of polyunsaturated fats, fish oil should not be used for cooking.
Flax oil contains lots of the plant form of Omega-3, Alpha Linolenic Acid (ALA).
The body doesn’t efficiently convert ALA to the active forms, EPA and DHA
Due to the large amount of polyunsaturated fats, flax seed oil should Not be used for cooking.
Canola oil is derived from rapeseeds, but a toxic, bitter substance has been removed from it.
The fatty acid breakdown of canola oil is mostly of monounsaturated fatty acids, containing Omega-6 and Omega-3 in a 2:1 ratio.
Nut Oils and Peanut Oil are very rich in polyunsaturated fats, which make them a poor choice for cooking.
Macadamia nut oil is mostly monounsaturated.
Industrial seed and vegetable oils are highly processed, refined products, that are too rich in Omega-6 fatty acids for cooking.
Incorrectly considered heart-healthy, new data links these oils with many serious diseases, including heart disease and cancer. :
Soybean oil
Corn oil
Cottonseed oil
Canola oil
Rapeseed oil
Sunflower oil
Sesame oil
Grapeseed oil
Safflower oil
Rice bran oil
Common vegetable oils on food shelves contain between 0.56 to 4.2% trans fats, which are highly toxic.
The main drivers behind oxidative damage of cooking oils are heat, oxygen and light.
The keto diet generally restricts carbohydrates intake to 20–50 grams per day.
Coconut oil also contains saturated fats, most of which are medium-chain triglycerides (MCTs), a type of fat that may boost fat burning.
Coconut oil is a very calorie-rich food, 120 calories per 1 tablespoon (14 grams).
Coconut oil is best suited for baking and pan-frying.
Avocado and olive oils are rich in monounsaturated fatty acids, which may support heart health and decrease inflammation .
All cooking oils are 100% fat, bit it is recommended that avoiding seed oils like soybean, corn, and sunflower oil, as they may promote inflammation and introduce cell-damaging free radicals.
Sautéing vegetables in extra virgin olive oil enriches them with natural phenols, a type of antioxidant linked to prevention of cancer, diabetes, and macular degeneration.
Fried foods usually have higher in calorie density than if it is not deep fried.
About 650,000 veterans had completed the MVP lifestyle survey of consumption of fried food, with over 150,000 (90% of whom were men), were included in the final analysis,
Compared to those who consumed fried food of any kind less than once per week, those who consumed fried food daily were 14% more likely to be diagnosed with coronary artery disease.
Those who ate fried food at least 1 time per week were 7% more likely to be diagnosed with coronary artery disease.
The risk of death from heart attack or stroke were statistically the same: 14% greater risk of death for those eating fried food daily or 7% greater risk of death for those eating fried food just once per week.
Meta-Analysis Provides Insight on Fried Food and its Impact on Heart Health
A meta-analysis of nearly 20 studies on the effects of consuming fried foods on cardiovascular health.
There is a direct link between consumption of fried food and increased risk of cardiovascular disease and all-cause mortality.
A meta-analysis suggests that for jevery additional serving of fried food per week is linked to a 3% increase in risk of major adverse cardiovascular events, a 2% increase in risk of coronary heart disease, and a 12% increase in risk of heart failure.
Limiting fried-food consumption reduces the amount of total fat intake and industrially produced trans-fatty acid intake for a healthy diet.
Meta analysis related to 562,445 individuals and 36,727 major cardiovascular events evaluating fried food consumption: When comparing those with the highest levels of fried food intake to those with the lowest: increased intake was associated with a 28% increase in risk of major cardiovascular events, a 22% increase in risk of coronary heart disease a 37% increase in risk of stroke, and a 37% increase in risk of heart failure, a 2% increase in risk of cardiovascular mortality and a 3% increase in risk for all-cause mortality.
In the United States, the vast majority of fried foods consumed are made in commercial deep fryers using corn oil, canola oil, soybean oil, or even animal fat.
Patients who consume the most fried foods are 22% more likely to develop CHD than those who consumed the least.
There is a 37% increased risk of heart failure for participants consuming the most fried foods compared with the least, and the same for stroke.
Cardiovascular mortality, on the other hand, increased overall by only 3% when comparing the highest consumption of fried foods with the lowest.