The holidays are challenging for most everyone's midsection but are they a factor in actual obesity rather than seasonal weight gain?   And are weekends just as detrimental?

Researchers at the University of Pittsburgh and Quinnipiac University say yes to both.  Even weekend eating patterns can have a significant impact.

J. Jeffrey Inman, a University of Pittsburgh professor of marketing and associate dean for research in the Joseph M. Katz Graduate School of Business, and coauthor Adwait Khare, Quinnipiac University professor of marketing, studied two years' worth of data on consumers' eating behavior and found that the quantity and quality of foods eaten during a meal and over the course of the day differs considerably on weekends and holidays.

Just as important as the daily caloric increase on weekends and holidays is the nutritional value of the food consumed, according to the research, which was published in the Fall 2009 issue of the Journal of Public Policy&Marketing. Labor Day barbeques and Thanksgiving Day feasts focus on family and friends bonding over tables laden with high-calorie foods. Because the quantity and quality of food consumed changes during these times, Inman suggests that the U.S. Department of Agriculture incorporate recommendations for holiday and weekend eating into its food pyramid guidelines.

Understanding eating patterns and knowing that a weekend can be just as dangerous to the diet as a holiday dinner arms consumers, doctors, and nutritionists with more knowledge to fight obesity, says Inman.