The typical American eats more than he or she did only a few decades ago, according to new research which suggests that the bigger portion sizes in recent years has had a significant role to play in today's obesity epidemic.
The new study from researchers at the University of North Carolina reveals that between 1977 and 1996, portion sizes for key food groups grew not only at fast food restaurants but also in homes and at conventional restaurants.
"Many people have thought that portion sizes might be on the rise, but until now, there have been no empirical data to document actual increases," said lead researcher Samara Joy Nielsen. "We think this is important information not only because it documents this trend, but also because obesity presents a growing health threat both in the United States and abroad."
From a sample of 63,380 people aged two and older, researchers analysed nationally representative data from the 1977-78 Nationwide Food Consumption Survey and three separate Continuing Surveys of Food Intake by Individuals.
Nielsen and fellow researcher Dr Barry M. Popkin calculated the average amounts of specific foods eaten in both calories and ounces at home, in restaurants and in fast food restaurants for each survey year.
"Portion sizes varied by food source, with the largest being consumed at fast food establishments and the smallest at restaurants," Nielsen said. "Between 1977 and 1996, portion sizes increased for salty snacks, desserts, soft drinks, fruit drinks, French fries, hamburgers, cheeseburgers and Mexican food."
And the differences were by no means minute. "The quantity of salty snacks increased by 93 calories or 0.6 ounces, soft drinks by 49 calories or 6.8 ounces, hamburgers by 97 calories or 1.3 ounces, French fries by 68 calories or 0.5 ounces and Mexican food by 133 calories, or 1.7 ounces," she added.
In conjunction with a considerable increase in portion size, the scientists highlighted the fact that the average American citizen is also doing far less exercise than in times of yore.
"Dietary patterns are rapidly shifting in the United States, and these changes are important contributors to the growing epidemic of obesity and diabetes facing Americans," said Popkin. "Clearly the problem is that Americans are eating too much food. The shifts in where we are eating, as well as the types of food and how much, are critical."
Value for money clearly plays an essential role in the increasingly copious portions on offer to the Americans. One wonders how the food manufacturer and retail trade will fare should they decide to cut the consumer waistline by reducing the size of portions. But the problem of obesity is too severe to be ignored. One day soon the US must make firm, decisive and undoubtedly dramatic, moves to tackle the problem.
Full findings of the report appear in the 22 January issue of the Journal of the American Medical Association.