The study, published in the Journal of the American Dietetic Association, finds a 2,000-calorie diet consisting entirely of advertised foods would contain 25 times the recommended servings of sugars and 20 times the recommended servings of fat.
However, the advertised foods would provide fewer than half the recommended servings of vegetables, dairy products and fruit.
Lead investigator Michael Mink of Armstrong Atlantic State University in Savannah, Ga., and colleagues analyzed 84 hours of prime time and 12 hours of Saturday morning broadcast television -- ABC, CBS, Fox and NBC -- over a 28-day period in 2004.
The advertised foods oversupplied protein, selenium, sodium, niacin, total fat, saturated fat, thiamin and cholesterol. The same foods under-supplied iron, phosphorus, vitamin A, carbohydrates, calcium, vitamin E, magnesium, copper, potassium, pantothenic acid, fiber and vitamin D.
"The public should be informed about the nature and extent of the bias in televised food advertisements," Mink said in a statement.