While Americans are spending just 9.6 percent of their income on food — an all-time low — the USDA’s Economic Research Service reports that 49 percent of the total food budget of Americans goes to purchasing food away from home, which is an all-time high.

Not surprisingly, the bulk of these away-from-home food dollars are spent at fast-food or takeout restaurants — those ever-present bastions of convenience and cheap eats. The United States has nearly 950,000 restaurants and food service outlets, and a hefty majority of them fit in the same category as McDonald’s and Domino’s Pizza.

Visiting and ordering from these places is OK, but a problem arises when Americans eat these foods each and every day, with no regard for the calories, fat, sodium and sugar content.

Doing so is a large part of what makes the United States the world’s fattest nation. Indeed, ERS data shows the increase in fast-food consumption that is associated with higher-calorie, less-nutritive meals closely parallels the rise of obesity in the U.S.

Granted, other factors, particularly an across-the-board lack of exercise for people of all ages, play a role in what the Centers for Disease Control and Prevention refers to as the obesity epidemic, but fast food is a formidable factor.

Two studies published in 2002 in the Journal of Nutrition and the Journal of the American Dietetic Association, each found that people consume roughly twice as many calories on average when dining out or purchasing takeout when compared to the preparation and consumption of their own meals at home.

Another study, published in 2009 in the journal Obesity, found that New Yorkers consumed an average of 857 calories when eating their lunch at fast-food chains, with 39 percent ordering over 1,000 calories.

Perhaps most worrisome is the finding that young children, who develop eating patterns in their early years, are consuming fast food as often as adults. As reported in 2004 in the journal Pediatrics, just less than one-fourth of children aged 4 to 8 are fed fast food on a daily basis.

Given these statistics, it’s no wonder that in 2003 the World Health Organization declared fast-food marketing and consumption as a “probable cause” of the consistent increase in worldwide obesity and especially that of the United States. Nor should it come as a surprise that policymakers and nutritional scientists see fast-food consumption as a clear target in the effort to curb the rise of obesity across America.

But it’s not what could be called an easy target. As stated, millions of Americans take advantage of the convenience of fast food each day, and it seems unlikely that any public campaign would significantly reduce their visits. Another possibility is raising taxes on the fast-food and restaurant industry, but such an action would be undeniably difficult given the size and power of the National Restaurant Association.

Instead, the policymakers’ idea is pretty simple: If more people are aware of the calories they’re ordering at restaurants, and, notably, the calories they are feeding their kids, more people will make smarter choices.

States from California to Maine have already passed laws requiring menu board labeling, and the Center for Science in the Public Interest CSPI reports that the practice has been fully implemented in Philadelphia; New York City; all of Westchester County, N.Y.; and King County, Wash.

Following the trend, federal menu labeling standards have been introduced in both the House and Senate.

The Menu Education and Labeling Act — the MEAL Act for short — was most recently introduced May 14, 2009, in the House and Senate by Rep. Rosa DeLauro, D-Conn., and Sen. Tom Harkin, D-Iowa. It would require “that food, beverages and meals served in restaurants and similar retail food establishments that are part of a chain with 20 or more outlets shall list, adjacent to each food item listed, on menus, menu boards and other signs, the total number of calories, grams of saturated plus trans fat and milligrams of sodium per menu item, as offered for sale, in a clear and conspicuous manner.”

At the joint announcement, DeLauro said, “Access to nutritional information at restaurants is more important than ever, particularly given that a number of studies link eating out with higher caloric intake and obesity. With few restaurants providing easy to use and easy to find nutrition information, the MEAL Act represents an incremental step toward combating increasing obesity rates.”

As DeLauro noted, legislation is necessary because while fast-food chains such as McDonald’s, Domino’s and Burger King do provide nutrition information, it is on their Web sites, on tray liners or in brochures — places consumers are highly unlikely to look before making their purchases.

Indeed, Yale psychologists reported in the April 2009 American Journal of Public Health that the vast majority of consumers do not access this information. In their study, they observed consumers’ behavior at New York City-area fast-food eateries such as McDonald’s and Burger King, and while all restaurants provided nutrition information in some form, only six out of 4,311 people actually took notice.

Reading this study, I wrote a column last spring and concluded that while the MEAL Act is no doubt well-intentioned, it would basically be worthless. As I put it, “Americans who choose to regularly eat at fast-food restaurants in the United States do not give a fig about the calories, fat or anything else that is in what they are about to order and eat. They care about price, taste and convenience. So while the MEAL Act is a nice thought and calls attention to what is essentially a nationwide pandemic, I am holding my breath on just how much it can change.”

And now, as I write, my foot is in my mouth. I was wrong and I am happy to admit it.

Three researchers at Stanford’s business school reported in January 2010 that menu labeling does in fact result in consumers ordering fewer calories. Using data from Starbucks in Boston, New York City and Philadelphia — where labeling has been mandated — they found that consumers are now ordering an average of 6 percent fewer calories per transaction than before the regulations were put in place.

Interestingly, they reported that consumers showed no difference in drink calories ordered, food calories were solely responsible for the reduction; that Starbucks average profits were not impacted whatsoever; and notably, that the subset of stores located near Dunkin’ Donuts actually increased their overall revenue after beginning to post.

If that wasn’t good enough, at the end of January 2010, a study was published in Pediatrics which suggested that menu labeling could have a significant impact at fast-food restaurants as well. Specifically, Dr. Pooja Tandon, researcher at the Seattle Children’s Research Institute and the study’s principal investigator, found that parents who were provided with the calorie content on a McDonald’s menu chose an average of 102 calories less for their children than parents who did not.

An e-mail Tandon sent said, “I think providing more information to consumers can only help, and hopefully will lead to lower calorie consumption from restaurants on a population level. What menu labeling does is that it gives consumers the tools to make better choices when they are eating out at restaurants. The more information they have, the better decisions they can make.”

Taking these studies as evidence, the MEAL Act can only help our nation battle obesity, an epidemic which not only impacts two-thirds of Americans’ lives but, as Senator Harkin said, contributes to the development of the chronic diseases that are responsible for 75 percent of the $2 trillion we spend on health care each year.

So send Senator Harkin a letter, it’s the next thing I’m going to do.

Steve Adams is a graduate student in journalism and mass communication from Annapolis, Md.