On Monday, the U.S. Department of Agriculture and the Department of Health and Human Services are set to release the seventh edition of the Dietary Guidelines for Americans, designed to give Americans a sense of what their diets need based on the newest food research.

But interpreting this information as a consumer can be tricky. After all, the numbers companies must print on packaged foods are only useful if you have a point of reference.

When you're deciding what to make for dinner, experts say that having a bit of background information allows you to make more informed decisions about the information you see on food labels.

"The most important thing there and that's why it's in bold is calories," said Keith-Thomas Ayoob, an associate clinical professor of pediatrics and registered dietitian at the Albert Einstein College of Medicine in New York. "That will determine whether someone gains or loses weight . Your body doesn't really care whether the calories come from sugar or fat when it comes to controlling weight."

As it says in the fine print, food labels are based on a 2,000 calorie diet but the number of calories you actually need can vary. The American Heart Association recommends consuming anywhere from 1,600 to 3,000 calories per day depending on your age, gender and lifestyle.

There is also some variation in how much you need of the different vitamins and minerals, based on your age. The daily values listed on food packages after each vitamin or mineral are based on the highest amount needed by any age group, Ayoob said, which ensures that anyone following the labels will be getting enough of the vitamin, if not a little extra.

Fat content is an important part of the food label . In addition to keeping your total fat intake below 65 grams a day, saturated fats are important to watch out for, Ayoob said. Sixty-five grams of fat holds 585 calories a little less than 35 percent of the recommended daily total. The advisory committee that made recommendations for the new guidelines said saturated fat should make up less than 7 percent of all calories eaten (down from 10 percent) meaning you should eat less than 16 grams of saturated fat in a day.

The amount of protein you need is based your weight. The Institute of Medicine recommends people consume 0.8 grams of protein per kilogram of body weight. Ayoob said you can obtain a rough calculation of how much protein you need by multiplying your weight in pounds by 0.4.

Perhaps the biggest change in the guidelines for food labeling from the advisory committee although it remains to be seen what makes it into the final guidelines is the new sodium recommendation, Ayoob said. The current recommendation is 2,300 milligrams (although it is listed at 2,400 on food packages). The advisory committee recommended reducing that number to 1,500 mg, a number currently used for people on low-sodium diets. But given how much sodium Americans eat now regularly exceeding the current guidelines actually limiting yourself to that lower sodium level may prove difficult.

"There are those of us in the field who think that's unrealistic for most people," Ayoob told MyHealthNewsDaily. And while the committee recommended the sharp reduction in sodium be done over time, they did not have a full plan for making that change.

With carbohydrates, Ayoob said people should limit sugar consumption and ensure they get enough fiber. This means getting at least 25 grams of fiber daily, and keeping your sugar intake under 32 g of added sugar ("added" sugars that are those not naturally occurring, such as corn syrup, brown sugar and dextrose). Reaching those goals usually involves comparing products, Ayoob said, because not all foods have fiber.

"Within a food category, choose foods that have the highest level of fiber," he said. For example, shoppers can choose their breads and cereals based on which have the most fiber. "That may be the best use of the nutrition facts panel, is when you compare food in like products foods in the same food category."

But while food labels may be useful , they do have one common pitfall.

"The biggest mistake is serving size and number of servings per container, and this is true especially with beverages," Ayoob said. Larger bottles may be labeled as two servings, although they are usually finished in one sitting so when you drink a bottle of a beverage that has 27 g of sugar per serving, you're really drinking 54 g.

They question you need to ask, Ayoob said, is, "Is that the number of servings it's going to be for you?"

Companies don't define what a serving looks like, and so shoppers need to figure it out. If a box of pasta has four 4-ounce servings, then you might empty it out at home and split it four ways to figure out whether that is really a meal.

But beyond that potential stumbling block of serving size, consumers should be able to use food labels to their advantage.

"People don't make as many mistakes when they look at the food label, they make mistakes when they don't." said Ayoob.

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