LONDON (AP) -- It may be obvious that most Britons are overweight. What isn't so obvious is that at least 2 million of them are likely malnourished -- and that includes some of the people who are too fat.

Experts say the poor state of the average British diet -- often high in fat, salt and calories, but low on nutrition -- means malnutrition is a problem even though food is plentiful.

"You can't always tell if a person is malnourished with your eyes," said Dr. Marinos Elia, a professor of clinical nutrition and metabolism at Southampton University. "People may be eating too much food, but they may not be eating enough fruits and vegetables."

Dr. Alastair McKinlay, a gastroenterologist and chairman of a British malnutrition action group, put it bluntly: "There's a widely held misconception that if you're fat, you can't be malnourished."

Some experts even contend that the food rationing system during World War II offered Britons more nutrition than what they're eating today. From 1939-45, Britons got books of coupons, which they traded in for limited amounts of items like flour, milk, eggs, meat and canned fruit.

"Rationing was a huge success because it ensured that if you got your allotted amounts, you got a nutritionally reasonable diet," said Dr. Colin Waine, chairman of the National Obesity Forum. "I'm not advocating a return to rationing, but it was a more balanced diet back then."

Despite the unlimited food supply today, Waine said people don't always make the right choices.

Many nutrition experts believe the number of malnourished Britons is closer to 4 million, about 6 percent of the population, than the government's estimate of 2 million.

Most malnourished people have a chronic illness like AIDS, cancer or tuberculosis. In the last five years, according to the Department of Health, the number of hospital-identified malnourished patients has risen by more than 40 percent, though experts say that is largely due to heightened surveillance rather than a dramatic jump in cases.

There are no statistics on how many obese people may be malnourished, but doctors say they are seeing patients who are both overweight and malnourished. According to government statistics, 75 percent of Britons are overweight; more than one-fifth are obese.

While malnourished fat people are hardly in danger of starvation, other health problems are possible along with obesity-related complications like diabetes and heart disease. Once they start losing weight, malnourished people may actually burn their own tissue, including muscle, rather than fat.

Usually, people with vitamin deficiencies have skin problems, a swollen thyroid or bleeding gums. In severe cases, malnourished people might also experience hair loss, muscle wasting, a swollen abdomen, anemia or rickets.

In a country like Britain, experts say, malnutrition is rarely noticed. "You've got to have pretty severe deficiencies before this is picked up," said Waine. "But I think a lot of people are on the borderline."

Part of the blame goes to the rise of processed and fast foods, most of which contain only small amounts of healthy nutrients. The national diet is in such trouble that earlier this month, the United Kingdom's Food Standards Agency recommended that folic acid be added to the nation's flour; a lack of it in the diet of pregnant women has been linked to birth defects.

Recent surveys estimate that fewer than 20 percent of adults eat the recommended five daily portions of fruits and vegetables.

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