Americans need to make big changes in their eating habits to fight the obesity epidemic and a host of ailments caused by poor diets, including consuming less sugar, fat and salt and more fish, fruits and vegetables, the Obama administration recommended Monday.

In updating the federal dietary guidelines - required by law every five years - the departments of Agriculture and Health and Human Services outlined a long list of steps Americans should take to eat better to boost their chances of living longer, healthier lives.

While the new guidelines contain no dramatic changes from previous iterations, they are intended to simplify many messages and emphasize certain recommendations more starkly, officials said. For example, the first major message reads simply: "Enjoy your food, but eat less."

The guidelines also make a point of highlighting the importance of minimizing salt consumption. No one should consume more than 2,300 milligrams of sodium per day - about one teaspoon of salt - while African Americans and those who are ages 51 and older, have high blood pressure, diabetes or chronic kidney disease should take in no more than 1,500 milligrams, according to the guidelines. The second group accounts for about half the U.S. population. The recommended limits are essentially unchanged from the previous guidelines.

Currently, Americans consume about 3,400 milligrams of sodium each day, which many experts say increases their risk for high blood pressure, a major risk factor for a variety of illnesses, including heart attacks and strokes. Officials noted that much of the sodium people consume is hidden in processed foods. So the reduction would require major changes by the food industry.

"This is obviously a significant reduction that is being proposed and one that we hope the food processors in particularly will take into account," Agriculture Secretary Tom Vilsack said.

But industry groups immediately criticized the proposal. The Salt Institute questioned the link between sodium and high blood pressure, arguing the recommendation would have a variety of negative effects on health, including worsening the obesity epidemic by driving people to eat more overall to satisfy their desire for salt.

"The guidelines, if followed, may have negative substantial unintended health consequences," said Morton Satin, the institute's vice president for science and research.

Although most people have probably never read the guidelines, they have a broad impact on Americans' lives, dictating what many students eat for breakfast and lunch at school, what people getting food stamps are urged to buy and what information is highlighted on packages lining supermarket shelves.

Because they are potentially so influential, the guidelines are typically the focus of intense political lobbying.

With so many Americans overweight and obese, officials said they hoped the new guidelines might finally help get the message across about how to eat a more healthful diet.

"This is a crisis we can no longer ignore," Vilsack said. "The bottom line is that most Americans need to trim our waistlines to reduce the risk of developing diet-related chronic disease. Improving our eating habits is not only good for every individual and family, but also for our country."

The new guidelines include 23 specific recommendations for the general population and six recommendations for specific groups, such as pregnant women.

Among the recommendations are:

l In general, avoid "oversized" portions.

l Drink water instead of beverages containing sugar.

l Eat more fruits and vegetables. A good rule of thumb is that half the food on your plate should be fruits and vegetables.

l Consume less than 300 milligrams of cholesterol each day.

l Alcohol should be consumed only in moderation, which means up to one drink per day for women and two drinks per day for men.

l Consume more fat-free or low-fat dairy products, such as low-fat milk, yogurt and cheese.

l Consume more seafood; use it to replace some meat and poultry. Breast-feeding women should consume 8 to 12 ounces of seafood per week from a variety of sources. But they should limit intake of white tuna to 6 ounces per week because of its high mercury content and eat no tilefish, shark, swordfish and king mackerel for the same reason.

"Helping Americans incorporate these guidelines into their everyday lives is important to improving the overall health of the American people," said Health and Human Services Secretary Kathleen Sebelius. "The new dietary guidelines provide concrete action steps to help people live healthier, more physically active and longer lives."

The guidelines were prepared by a committee of experts that conducted an exhaustive review of the scientific literature about diet, exercise and health, as well as hundreds of public comments and testimony at a series of public meetings.

"I never would have believed they could pull this off," said Marion Nestle, a vocal food industry critic at New York University. "The new guidelines recognize that obesity is the number one public health nutrition problem in America and actually give good advice about what to do about it: eat less and eat better. For the first time, the guidelines make it clear that eating less is a priority."

But Nestle and others said they wished the guidelines went further in several areas.

"Without even more serious governmental efforts - such as banning artificial trans fat and limiting sodium in packaged foods - the dietary guidelines will not be sufficient to fend off the costly and debilitating diet-related illnesses that afflict millions of Americans," said Margo G. Wootan of the Center for Science in the Public Interest.

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