Are you a frequent diner-about-town? If so, it could be making you fat. The USDA has been examining the relationship between restaurant food and obesity, and it turns out that eating just one meal a week outside the home correlates to roughly two extra pounds a year.

Non-shocker: in comparison to homemade meals, restaurant portion sizes are larger, higher-calorie, and filled with inexpensive, obesity-promoting foods like processed grains and trans fats, all factors that certainly promote weight gain. That's a staggering statistic when combined with the fact that more than half of all American adults eat out more than three times per week.

Are you one of them — and if so, are you worried about its long-term impact on your waistline?