There are dozens of diets with different and often contradictory advice for how to lose pounds and maintain a healthy weight, but there’s one thing on which they almost all agree: fried foods are bad for your health. Recent research, however, suggests it might not be that simple. In one study, subjects with the most fried food consumption had about the same risk of coronary heard disease and a lower mortality rate than those with the least.
Of course, that isn’t as simple as it sounds either. The type of oil used, for example, makes a big difference in the outcome. The people in that study were eating food fried generally in sunflower oil or olive oil, and another study found that food fried in extra-virgin olive oil can lower insulin levels. Other oils and fats—the ones more commonly used at all but the highest-end restaurants—are less healthy. Fried foods may not cause heart disease, but they are high in calories. Reusing cooking oil can also change it from neutral or beneficial to a danger. Reheating sunflower oil after it has been used once, for example, releases compounds called aldehydes, which can cause cancer in high amounts. One reuse is generally safe, but the risk increases after that.
Nonetheless, there is some evidence that some of the reputation of fried foods is guilt by association, in which a diet high in fried foods also tends to include a lot of fast-food meals, a high salt intake, a lot of processed foods, and other unhealthy choices. Fried foods aren’t harmful in moderation—and nearly anything eaten immoderately is bad for you—but they’re often served as part of meals that are. The study that found no harm was done in Spain, and the standard Mediterranean diet is famously heart-healthy; it may well be that the benefits of the overall diet compensated for the health problems caused or exacerbated by frying.
Moreover, the foods people choose to fry are often questionable no matter how they’re prepared. Deep-fried cola, a dessert invented at the Texas state fair, is probably bad for your health, but cola in any form is bad for your health. Frying vegetables, on the other hand, doesn’t rob them of nutritional value, and while the results may not be better for you than vegetables cooked by other methods, it’s an improvement over deep-fried junk food.