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Balancing act

New dietary guidelines emphasize calories in, calories out

March 7, 2011

The latest edition of the U.S. government’s Dietary Guidelines for Americans puts “more emphasis than ever” on balancing calorie intake and physical activity to maintain weight and health, says MIT Medical nutritionist Anna Jasonides, R.D.,L.D.

Since 1980, the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS) have jointly issued updated dietary recommendations every five years, based on the latest scientific and medical knowledge. The 2010 edition, released on January 31, 2011, encourages Americans to choose healthier foods in the right portions and to complement those choices with physical activity. For the first time, the document devotes an entire chapter to “Balancing Calories to Manage Weight,” a response to the fact that most American adults and one in three children are overweight or obese.

“This report seems more thoughtful and specific than previous editions,” Jasonides says. “It’s saying, ‘Hey, Americans, wake up! We need to eat fewer calories, and we have to figure out how much we need to eat’. People don’t realize how few calories they actually need.

“So many medical conditions are correlated with being overweight—type 2 diabetes, high cholesterol, heart disease, high blood pressure, sleep apnea, even some cancers,” she adds.

Eat this; don’t eat that.

Along with reducing calories, the guidelines also encourage Americans to think more about the sources of the calories they consume—and to consume fewer calories of certain types. “In the past, the guidelines tended to focus on what you should eat more of,” Jasonides explains. “‘Eat more fruits. Eat more vegetables.’

“Given the powerful food lobby, it’s a lot harder for them to say, ‘Eat less of this and that’,” she continues. But this year, Jasonides notes, the guidelines contain a whole chapter entitled “Foods and Food Components to Reduce,” which includes recommendations to consume more “nutrient-dense” foods and drinks and to cut back on calories from “solid fats, added sugars, and refined carbohydrates.” The chapter also lists foods that are the major sources of these problematic food components. For example, soda, energy drinks, and sports drinks are cited as the major sources of “added sugar” in the American diet, and pizza is singled out as a major source of “solid fats.”

“In a nutshell, they’re saying ‘Eat less processed junk food’,” Jasonides says. “It’s a lot more explicit than they’ve ever been before.”

Hold the salt

The new guidelines also take aim at sodium intake. Excess dietary sodium is strongly correlated with high blood pressure for many people, Jasonides explains, and high blood pressure is a major risk factor for stroke, heart attack, and other cardiovascular conditions.

Previous recommendations were to limit daily sodium intake to 2,300 milligrams for “healthy adults.” A lower limit, 1,500 milligrams, was recommended for African-Americans, people with high blood pressure, and anyone “middle-aged or older,” Jasonides recalls. But this year’s guidelines also recommend lower sodium intake for people with diabetes and chronic kidney disease and explicitly call for the 1,500-milligram daily limit to begin at age 51. “This recommendation now applies to more than half of the U.S. population,” Jasonides notes.

To limit dietary sodium, she suggests choosing “food in its natural state” as often as possible. This includes fresh fruit and vegetables and fresh meat. Ready-to-eat foods—those that are canned or boxed, those that just need to be heated, or “anything that contains a spice packet”—are the biggest sodium culprits, Jasonides says. “If you do buy prepared foods, read and compare food labels so you can choose foods with less sodium,” she advises.

In addition, she notes, “When you think about why processed foods have so much sodium in the first place, those foods seem much less appealing. Salt is added to processed foods as a preservative—to inhibit the growth of bacteria, yeast, and mold. It’s also used to mask metallic or chemical aftertastes in products such as soft drinks.”

Start with a few small steps

The best way to gain more control of calories, sodium consumption, and other nutritional factors in your diet is to buy fresh food and cook at home as often as possible, Jasonides says. But no one should expect to change all their eating habits overnight, she cautions.

“Start with a few small steps,” she suggests. “Begin by eating one more meal at home each week than you currently do. Go vegetarian one day a week. Try making your own salad dressing if you routinely use bottled dressings.

“Small changes add up,” she says, “And over time, they can make a big difference.”

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