No associations were found for deaths from cardiovascular disease or from any cause, but the researchers said this might be because of the relatively small numbers involved in some of the studies.
When food is fried, it absorbs some of the fat from the oil, potentially increasing calories. In addition, commercially fried and processed foods can often contain trans fats, created by an industrialized process that adds hydrogen to liquid vegetable oils to make them more solid (think of semisoft margarine and shortening).
The food industry loves trans fats because they are cheap to produce, last a long time and give foods a great taste and texture.
Besides fried foods, you’ll find trans fats in coffee creamer, cakes, pie crusts, frozen pizza, cookies, crackers, biscuits and dozens of other processed foods.
There is still a loophole, however. The FDA allows companies to label a food as “0 grams” of trans fats if one serving of the food contains less than 0.5 grams.
Only an association
Despite the evidence behind the health impact of trans fats, this meta analysis of studies can only show an association between consumption of fried foods and cardiovascular risk.
The “findings of this study are consistent with current guidance to limit intake of fried foods but cannot be considered as providing definitive evidence on the role of fried food consumption in cardiovascular health,” said Alun Hughes, professor of cardiovascular physiology and pharmacology at University College London, in a statement. Hughes was not involved in the study.
That’s because most studies of this kind reply on study participants’ recall of the amount and type of fried foods eaten, which is subject to error. In addition, high consumption of fried foods is likely to be associated with overeating and obesity, lack of exercise and other unhealthy behaviors that can contribute to heart disease, experts said.
“If the relationship is causal, we can’t assume that this association is definitely down to the fat content of the foods, as many of these foods are highly processed and often contain both fat and carbohydrate together,” said registered dietitian Duane Mellor, a senior teaching fellow at Aston Medical School in Birmingham, United Kingdom.
“So, when considering this type of study, it is important to consider that although reducing fat intake is a logical part of a healthy diet, it is also important to look at what foods are eaten in its place,” said Mellor, who was not involved in the study.