It turns out that treating yourself to a meal at a fancy restaurant is just as bad for your waistline as chowing down on fast food.

Those of us who dine out – rather than cook at home – consume about 200 more calories a day, and the result is the same whether you go to McDonald's or any other type of dining establishment, according to a study led by the University of Illinois at Urbana-Champaign.

"These findings reveal that eating at a full-service restaurant is not necessarily healthier than eating at a fast food outlet," said study leader Ruopeng An, who analysed data collected from 18,098 adults living in the U.S. between 2003 and 2010.

He continues: "In fact, you may be at higher risk of overeating in a full-service restaurant than when eating fast food. My advice to those hoping to consume a healthy diet and not overeat is that it is healthier to prepare your own food, and to avoid eating outside the home whenever possible."

The report, published in the European Journal of Clinical Nutrition, showed that restaurant diners tend to take in more healthy nutrients – including certain vitamins, potassium and Omega-3 fatty acids – than those who eat at home or at a fast food outlet.  But they also consume substantially more sodium and cholesterol – two nutrients that people from Western countries tend to eat in excess, even at home.

People eating out consumed about 10 grams more total fat, and more saturated fat (3.49 grams and 2.46 grams respectively), than those who dined at home.

The study also showed striking differences in the effects of dining out on different groups. "African-Americans who ate at fast food and full-service restaurants took in more total fat, saturated fat, sodium and sugar than their Caucasian and Hispanic counterparts who dined out," explains the University of Illinois kinesiology and community health professor.