We knew we ate more; we knew we had gained weight. Now a new study that looked at 30 years of Americans' eating habits has pinned down how many more calories, carbohydrates and fats are eaten daily.
From 1971 to 2000, the study found, women increased their caloric intake by 22 percent, men by 7 percent.
Much of the change was found to be due to an increase in the amount of carbohydrates we have been eating. The findings may reinforce the current trend among those sometimes known as carb-avoids, of reducing or even eliminating foods like breads and pasta.
And while the percentage of calories Americans get from fat, especially saturated fats, has decreased, the numbers might be deceiving. The actual amount of fat eaten on a daily basis has gone up. It just makes up a smaller percentage of the total caloric pie now that we are eating so many more carbs.
The study, conducted by the Centers for Disease Control and Prevention and reported in its current Morbidity and Mortality Weekly Report, found that in 1971, women ate 1,542 calories on average, compared with today's 1,877, while men went from 2,450 calories a day to 2,618. The government recommends 1,600 calories a day for women and 2,200 for men.
Cookies, pasta, soda and other carbohydrates appear to be mostly to blame. Among women, carbs jumped from about 45 percent of the daily caloric intake to almost 52 percent. For men, they grew from 42 percent to 49.
"This just confirms that Americans need to be more focused on a total calorie decrease," said Jacqueline Wright, an epidemiologist at the CDC and the author of the study.
According to the report, most of the surge in caloric intake occurred in two periods, from 1976 to 1980 and from 1988 to 1994. An earlier report by Dr. Lisa Young of New York University tied that increase to decisions by national restaurant chains to expand portions of foods such as French fries and hamburgers. Serving sizes, Young found, became two to five times bigger in those years, and cookbooks joined the trend by increasing the portion sizes in recipes.
It is no surprise, said Dr. Gary Foster, the clinical director of the weight and eating disorders program at the University of Pennsylvania School of Medicine, that "we've become more overweight as a country as candy bars are now king-sized and sodas are supersized.
"It's much tougher to manage your weight in this environment than it was in 1970," Foster said.
Part of the problem, some experts say, may stem from the traditional dietary advice to steer clear of fatty foods. That advice, they say, helped set off an explosion of "fat-free" carbohydrate-laden foods that Americans mistakenly believed they could eat with few consequences.
"It's been the standard advice for decades that Americans should follow lower-fat, high-carb diets," said Dr. Meir Stampfer, a professor of epidemiology and nutrition at the Harvard School of Public Health.
"But now it's backfiring. It's clear that this doesn't work because it's not as satiating and people just start eating more calories. This report doesn't demonstrate that, but the results are consistent with it."