A new study suggests eating fried and junk foods, that most of us love to gorge on, have enough trans-fats, salt and sugar to lead us to an early onset of obesity and related chronic diseases, in people with genetic risk.

Salt in fried food, however, is not the real problem, but, consuming trans-fats, or the 'bad fats' is a big threat.

A team of US researchers analysed data from 9,623 women in the Nurses' Health Study, 6,379 men in the Health Professionals Follow-up Study and 21,426 women in the Women's Genome Health Study.

Participants filled out food frequency questionnaires, which was based on how often they ate fried food consumption - both at home and away from home. Body mass index (BMI) and lifestyle factors, such as physical activity, were also assessed. Genetic risk scores were calculated based on genetic variants associated with BMI.

The results of the study showed that regular consumption of fried foods was associated with higher BMI, after taking into account other dietary and lifestyle factors.

In addition, the study showed that the association between overconsumption of fried foods and obesity was particularly pronounced among people with a greater genetic predisposition to obesity. On the other hand, the genetic effect on BMI among those who ate fried foods more than four times a week was about twice as large compared with those who ate them less than once a week.

The study has been published in the British Medical Journal.