Such unhealthy meals can result in blood vessels in a chronic state of inflammation, a primary factor in the development of atherosclerosis, say the researchers. The research lends weight to the benefits of adopting a healthy diet low in fat and high in fruits and fibre to help protect against heart disease.
Endocrinologists at the university of Buffalo in the US carried out a study on nine normal-weight subjects who ate a 900-calorie breakfast - consisting of a fried egg sandwich and hash browns - after an overnight fast.
Another eight normal-weight subjects drank 300 millilitres of water as a control group. Blood samples were taken before eating or drinking and at 1, 2 and 3 hours afterward. The samples were analysed to determine the concentration of inflammatory mediators and oxygen free radicals.
The study focused on a pro-inflammatory factor called nuclear factor-kappa B (NF-kB), which regulates the production of several inflammatory mediators and free radicals.
"This pathway was activated in all subjects following food intake and resulted in the production of several inflammatory mediators regulated by it," said Ahmad Aljada first author on the study, published in the April issue of the American Journal of Clinical Nutrition (79: 682-690).
Levels of inflammatory factors remained high for three-to-four hours after the high-fat meal, research showed.
"People who experience repeated short-lived bouts of inflammation resulting from many such unhealthy meals can end up with blood vessels in a chronic state of inflammation, a primary factor in the development of atherosclerosis," Aljada said.
"However, we've also shown in a study accepted, but not yet published, that a breakfast containing the same number of calories but derived mostly from fruit and fibre doesn't promote the inflammatory effect."
The researchers hypothesise that the influx of macronutrients (calories, fat, protein, carbohydrates and water) may alter cell behaviour and activate genes to produce more powerful enzymes and mediators that potentially are more damaging to the lining of blood vessels.
"The magnitude of this acute and transient effect is dependent on the type of macronutrient and may lead eventually to a chronic pro-inflammatory and pro-oxidative state, as seen in obesity," said Aljada. "This, in turn, leads to several medical complications."
Results also showed a mean increase of free radicals over baseline of 129 per cent, 175 per cent and 138 per cent at the three sampling times, respectively.
The study findings provide strong support for adopting a healthy diet low in fat and high in fruits and fibre to help protect against heart disease, Aljada said.