The study done with University of Minnesota researchers says the findings may suggest that fast food increases the risk of obesity and Type 2 diabetes.

The findings are published in this week's issue of Britain's THE LANCET.

Mark A Pereira of the University of Minnesota, David S Ludwig of the Children's Hospital Boston, and colleagues investigated the association between reported fast-food habits and changes in bodyweight and insulin resistance over a 15-year period in the United States.

Over 3,000 young black and white adults were followed up with repeated dietary assessment.

"Fast-food habits have strong, positive, and independent associations with weight gain and insulin resistance in young black and white adults." Ludwig said.

"Fast-food consumption can be linked to adverse health outcomes through plausible mechanisms, and results from other studies lend support to our findings. In view of the high and increasing rates of fast-food consumption, further research into the effects of this dietary pattern on public health should be given priority."