Just a heads up for people on Sci Am

nesf

This month's Scientific American is a special issues on Diet, Health and Food Supply. I haven't had a chance to read through it yet but I thought that quite a few people on here who mightn't normally read Sci Am might find it very interesting this month.

Of particular interest might be the "Can Fat be Fit?" article..

g'em

Great find nesf, thanks! I have full access to those journals and there's some really interesting stuff there - will I be breaking a gazillion copywrite laws if I put up some of the articles here?

g'em

Meh, I'll put some of them up anyway, if they need to be taken down so be it.

Scientific American, Sep 2007, Vol. 297, Issue 3 wrote:

Take Nutrition Claims with a Grain of Salt

Dietary studies sponsored by the food industry are often biased

Although we are what we eat, we are by no means only what we eat. Some people, for instance, can consume all the fatty foods they want-- meat, cheese, butter, ice cream--but somehow manage to stay rail-thin and enjoy low blood triglyceride levels, whereas others living on the same rich fare would soon develop potbellies and clogged arteries. The significant genetic and metabolic variation among individuals makes it almost impossible for experts to prescribe detailed nutritional recommendations that work optimally for everybody. As nutritionist Marion Nestle recommends in her article "Eating Made Simple," beginning on page 60, the best we can do today is to adhere to the time-honored advice to eat less; exercise more; eat mostly fruits, vegetables and grains; and avoid junk foods. But this basic regimen leaves many concerned Americans with unresolved issues about dietary choices, especially those regarding specific foods promoted by food companies and their lobbyists: Is milk bad for adults? Should I eat more fish? Are organic foods better? More specific guidance regarding food selection would help.

Regrettably, determining the actual health value of organics, fish, milk or any other single foodstuff or nutrient is no easy task, nor is it cheap. The complexity of nutrition and its subtle effects on human well-being mean that researchers must mount large, long-term studies to try to distinguish among multiple, interrelated nutritional factors that affect health. But big test group populations are costly to monitor accurately and difficult to control over time.

Despite the complexities, such large-scale nutrition-related studies are important because they help to shape how government and professional authorities formulate dietary guidelines, how administrators design public health programs and how agencies regulate company health claims for food products. The popular media publicize these findings widely, which directly affects consumer behavior. More and more, the commercial success of food products depends on what science says about the effects of these foods on health. Yet all too often the sources of the science are the commercial interests themselves.

Although government agencies as well as some charities and activist groups sponsor major nutrition experiments in the public's interest, these organizations often lack sufficient resources to conduct the research that might more fully inform people about what to eat. Given the chance to gain favorable, peer-reviewed publicity for their products, food companies frequently fill the research-study funding gap and then vigorously promote any results that support consuming a specified daily amount of one of their foods.

Unfortunately, food industry money seems to distort nutrition studies, according to the first systematic effort to measure sponsorship bias in nutritional research. That analysis appeared in a paper published this past January in the Public Library of Science Medicine. A research team at Children's Hospital Boston performed a meta-analysis of 206 nutrition-related studies on milk, juice and soft drinks conducted from 1999 to 2003. Of the 111 that had declared financial sponsorship, 54 percent were at least partly funded by industry. Industry-supported studies were four to seven times more likely to favor their sponsors than research paid for by disinterested parties.

The influence of sponsors may be unconscious, the investigators suggest, and could occur at many levels, manifested by how researchers pose questions in the hypothesis, how they design studies, which data they collect or do not collect, how they analyze the data and how they derive their conclusions.

Critics have also noted that the Children's Hospital group may have distorted the study's findings by failing to include in their analysis nutrition research funded by the U.S. Department of Agriculture (presumably the critics believe that government-supported investigations are more likely to be free of industry influence).

The realization that all organizations-- including the government, as well as industry and activist groups--tend to finance research that is aligned with their interests seems to lead to a straightforward solution. Because nutrition re search is important to helping the public make healthy food choices, it only makes sense to find public monies with which to support the independent studies needed to develop the necessary guidelines.

People, we think, are likely to deem it worthwhile to pay a bit to find out what ever science can legitimately say about what to eat.

g'em

The article nesf mentioned...

[QUOTE=Raeburn, P., Scientific American, Sep 2007, Vol. 297, Issue 3
]

Can Fat be Fit?

A well-publicized study and a spate of popular books raise questions about the ill effects of being overweight. Their conclusions are probably wrong

KEY CONCEPTS
• A much discussed 2005 study showed that people at a "healthy" weight have higher mortality than those who are overweight.


• At about the same time, several popular books-- under the banner of fat but fit--derided the notion that being overweight is necessarily unhealthy.


• This challenge to the prevailing orthodoxy continues to provoke ardent debate. But most nutrition experts still warn about the consequences of carrying extra pounds.


• The health-conscious, nutritionists counsel, should use the body mass index based on height and weight as a gauge to judge proper weight.



Two years ago Katherine M. Flegal, a researcher at the Centers for Disease Control and Prevention, did a new statistical analysis of national survey data on obesity and came to a startling conclusion: mildly overweight adults had a lower risk of dying than those at so-called healthy weights.

Decades of research and thousands of studies have suggested precisely the opposite: that being even a little overweight is bad and that being obese is worse. The distinction between overweight and obese--which are sometimes both classified under the rubric of obesity--can be confusing. It relates to the measure called body mass index (BMI), derived by dividing one's weight in kilograms by the square of one's height in meters. A myriad of Internet-based calculators will handle the math for you. The only thing to remember is that a BMI of at least 25 but less than 30 is considered overweight, and one of 30 or more is characterized as obese.

The long-established conventional wisdom holds that Americans carrying excess fat are at increased risk of death from heart disease, diabetes and various kinds of cancer. And those who do not die of obesity-related ailments can possibly look forward to a variety of other unpleasant consequences of their weight, including diabetes and its complications, such as the loss of an arm or leg, blindness and kidney failure. That has been the consensus view of most experts for decades, and it has not changed.

Just as Flegal's study appeared, a series of books--by lawyers, journalists, political scientists and other academics outside the medical profession--was published, all challenging conventional wisdom on obesity. Fat, the critics said, was not as bad as we had been led to believe. Furthermore, they said, the research community that condemned obesity had a financial stake in that point of view because of the scientists' complex ties to drugmakers and weight-loss clinics.

The flow of critical books has continued. Earlier this year Barry Glassner, author of the best-selling book The Culture of Fear (Basic Books, 2000), published The Gospel of Food: Everything You Think You Know About Food Is Wrong (Ecco, 2007). He argues that if we paid more attention to enjoying our food, rather than dieting and counting calories, we would be happier and healthier. It is an appealing argument, but Glassner, a sociologist at the University of Southern California, has not done any research studies to show whether it is true.

The stakes in this debate are high. A major thrust of the nation's disease prevention efforts are aimed at ending what orthodox researchers say is an epidemic of obesity. If being overweight or obese is as harmful as these investigators say, the associated health care costs constitute a substantial drag on the American economy. The CDC estimated in 2004 that obesity's costs in health care and lost productivity amount to $75 billion annually. Put an end to the fattening of America, these researchers say, and Americans will be healthier, live longer and pay less for their medical care. We might even see gains in American competitiveness, with growth in jobs and wages.

If too much fat is not an important cause of heart disease and other serious illnesses--the possibility raised by Flegal and other critics-- then efforts to trim American waistlines are entirely misplaced. Many of the leaders in the obesity research community dismiss the criticism. "It's complete nonsense, and it's obviously complete nonsense, and it's very easy to explain why some people have gone astray," says Meir Stampfer, a professor of nutrition and epidemiology at the Harvard School of Public Health. Stampfer and his Harvard colleague Walter Willett have done a series of decades-long studies involving hundreds of thousands of people that have laid the foundation for much of what is known about the dangers of being overweight or obese.

Stampfer cites the Flegal study as a prime example of the errors the critics make. The reason being overweight seemed to reduce mortality is because Flegal used the wrong comparison group, he says. The lean group in her study included smokers and people with chronic illnesses--both of whom have increased mortality risks, but not because they are slim. "When you get sick, you lose weight, and you die," Stampfer says. Compared with those who are smokers or chronically ill, people who are overweight come out looking better than they should.

Willett points to a November 2006 study by James A. Greenberg, a researcher at Brooklyn College, to prove his point. Greenberg performed a similar statistical analysis to Flegal's, this time adjusting for factors such as a history of serious illness. When he did, the number of extra deaths for the obese--compared to those with a "healthy" weight--tripled. And he found a significant increased mortality risk in those who were merely overweight, contrary to Flegal's finding that being overweight lowered the risk of death.

Flegal has acknowledged that she did not exclude the chronically ill from her study but argued in a follow-up report that she had done further analyses that showed it would not have made a difference. The disagreement turns on subtle statistical arguments. What is clear, however, is that Flegal's paper is one of a handful that contradict many studies that support the conclusion that being overweight is harmful. Flegal is not necessarily wrong, but the preponderance of evidence clearly points in the other direction.

Willett thinks this assertion is simply the latest recycling of the notion that Americans have been somehow duped about the risks of obesity. "About every 10 years this idea comes along that says it's better to be overweight. And we have to stomp it out," he says. Willett's research has identified profound advantages to keeping weight down--even below the so-called healthy levels.

Many Americans find it difficult to get under a BMI of 25, the border between the overweight and healthy groups. But Willett's work suggests that losing more weight is even better. To take one example, people with a BMI of 20 who gain enough to reach a BMI of 25 have quadrupled their risk of diabetes, Willett says. "If they go up over a BMI of 30, they've increased their risk of diabetes 30- to 60-fold," he says.. "And diabetes is not a good thing to have."

So, in light of conflicting evidence, what is the state-of-the-art summary of the conventional wisdom ? Willett puts it this way: keep an eye on three numbers. One is your BMI--keep it within the normal range (20 to 24.9), and preferably near the low end of that range. The second is your weight change after age 20. Although obesity has become increasingly common in children, most people who are now adults were probably close to their proper weight when they were 20, he says. Try to get back to that. The third number is waist circumference--if your belt size has increased since you were 20, that is something to reverse, too.

The consequences of working on these three numbers, he says, will be "huge benefits in health." But even small reductions in weight are beneficial. "If people can lose 5 to 10 percent of their weight, they will have done themselves a huge favor. If they can take another step, another 5 to 10 percent, they will have done themselves another favor." Some of the details have changed--but that is the same advice obesity experts have been dispensing for years.[/QUOTE]

g'em

And the one I found most interesting, probably because I don't agree with all of it!!

Nestle, M., Scientific American, Sep 2007, Vol. 297, Issue 3 wrote:

EATING MADE SIMPLE

How do you cope with a mountain of conflicting diet advice?

As a nutrition professor, I am constantly asked why nutrition advice seems to change so much and why experts so often disagree. Whose information, people ask, can we trust? I'm tempted to say, "Mine, of course," but I understand the problem. Yes, nutrition advice seems endlessly mired in scientific argument, the self-interest of food companies and compromises by government regulators. Nevertheless, basic dietary principles are not in dispute: eat less; move more; eat fruits, vegetables and whole grains; and avoid too much junk food.

"Eat less" means consume fewer calories, which translates into eating smaller portions and steering clear of frequent between-meal snacks. "Move more" refers to the need to balance calorie intake with physical activity. Eating fruits, vegetables and whole grains provides nutrients unavailable from other foods. Avoiding junk food means to shun "foods of minimal nutritional value"--highly processed sweets and snacks laden with salt, sugars and artificial additives. Soft drinks are the prototypical junk food; they contain sweeteners but few or no nutrients.

If you follow these precepts, other aspects of the diet matter much less. Ironically, this advice has not changed in years. The noted cardiologist Ancel Keys (who died in 2004 at the age of 100) and his wife, Margaret, suggested similar principles for preventing coronary heart disease nearly 50 years ago.

But I can see why dietary advice seems like a moving target. Nutrition research is so difficult to conduct that it seldom produces unambiguous results. Ambiguity requires interpretation. And interpretation is influenced by the individual's point of view, which can become thoroughly entangled with the science.

Nutrition Science Challenges
This scientific uncertainty is not overly surprising given that humans eat so many different foods. For any individual, the health effects of diets are modulated by genetics but also by education and income levels, job satisfaction, physical fitness, and the use of cigarettes or alcohol. To simplify this situation, researchers typically examine the effects of single dietary components one by one.

Studies focusing on one nutrient in isolation have worked splendidly to explain symptoms caused by deficiencies of vitamins or minerals. But this approach is less useful for chronic conditions such as coronary heart disease and diabetes that are caused by the interaction of dietary, genetic, behavioral and social factors. If nutrition science seems puzzling, it is because researchers typically examine single nutrients detached from food itself, foods separate from diets, and risk factors apart from other behaviors. This kind of research is "reductive" in that it attributes health effects to the consumption of one nutrient or food when it is the overall dietary pattern that really counts most. For chronic diseases, single nutrients usually alter risk by amounts too small to measure except through large, costly population studies. As seen recently in the Women's Health Initiative, a clinical trial that examined the effects of low-fat diets on heart disease and cancer, participants were unable to stick with the restrictive dietary protocols. Because humans cannot be caged and fed measured formulas, the diets of experimental and control study groups tend to converge, making differences indistinguishable over the long run--even with fancy statistics.

It's the Calories
Food companies prefer studies of single nutrients because they can use the results to sell products. Add vitamins to candies, and you can market them as health foods. Health claims on the labels of junk foods distract consumers from their caloric content. This practice matters because when it comes to obesity--which dominates nutrition problems even in some of the poorest countries of the world--it is the calories that count. Obesity arises when people consume significantly more calories than they expend in physical activity.

America's obesity rates began to rise sharply in the early 1980s. Sociologists often attribute the "calories in" side of this trend to the demands of an overworked population for convenience foods--prepared, packaged products and restaurant meals that usually contain more calories than home-cooked meals.

But other social forces also promoted the calorie imbalance. The arrival of the Reagan administration in 1980 increased the pace of industry deregulation, removing controls on agricultural production and encouraging farmers to grow more food. Calories available per capita in the national food supply (that produced by American farmers, plus imports, less exports) rose from 3,200 a day in 1980 to 3,900 a day two decades later [see box on opposite page].

The early 1980s also marked the advent of the "shareholder value movement" on Wall Street. Stockholder demands for higher short-term returns on investments forced food companies to expand sales in a marketplace that already contained excessive calories. Food companies responded by seeking new sales and marketing opportunities. They encouraged formerly shunned practices that eventually changed social norms, such as frequent between-meal snacking, eating in book and clothing stores, and serving larger portions. The industry continued to sponsor organizations and journals that focus on nutrition-related subjects and intensified its efforts to lobby government for favorable dietary advice. Then and now food lobbies have promoted positive interpretations of scientific studies, sponsored research that can be used as a basis for health claims, and attacked critics, myself among them, as proponents of "junk science." If anything, such activities only add to public confusion.

Supermarkets as "Ground Zero"
No matter whom I speak to, I hear pleas for help in dealing with supermarkets, considered by shoppers as "ground zero" for distinguishing health claims from scientific advice. So I spent a year visiting supermarkets to help people think more clearly about food choices. The result was my book What to Eat.

Supermarkets provide a vital public service but are not social services agencies. Their job is to sell as much food as possible. Every aspect of store design--from shelf position to background music--is based on marketing research [see center item on page 68]. Because this research shows that the more products customers see, the more they buy, a store's objective is to expose shoppers to the maximum number of products they will tolerate viewing.

If consumers are confused about which foods to buy, it is surely because the choices require knowledge of issues that are not easily resolved by science and are strongly swayed by social and economic considerations. Such decisions play out every day in every store aisle.

Are Organics Healthier?
Organic foods are the fastest-growing segment of the industry, in part because people are willing to pay more for foods that they believe are healthier and more nutritious. The U.S. Department of Agriculture forbids producers of "Certified Organic" fruits and vegetables from using synthetic pesticides, herbicides, fertilizers, genetically modified seeds, irradiation or fertilizer derived from sewage sludge. It licenses inspectors to ensure that producers follow those rules. Although the USDA is responsible for organics, its principal mandate is to promote conventional agriculture, which explains why the department asserts that it "makes no claims that organically produced food is safer or more nutritious than conventionally produced food. Organic food differs from conventionally grown food in the way it is grown, handled and processed."

This statement implies that such differences are unimportant. Critics of organic foods would agree; they question the reliability of organic certification and the productivity, safety and health benefits of organic production methods. Meanwhile the organic food industry longs for research to address such criticisms, but studies are expensive and difficult to conduct. Nevertheless, existing research in this area has established that organic farms are nearly as productive as conventional farms, use less energy and leave soils in better condition. People who eat foods grown without synthetic pesticides ought to have fewer such chemicals in their bodies, and they do. Because the organic rules require pretreatment of manure and other steps to reduce the amount of pathogens in soil treatments, organic foods should be just as safe--or safer--than conventional foods.

Similarly, organic foods ought to be at least as nutritious as conventional foods. And proving organics to be more nutritious could help justify their higher prices. For minerals, this task is not difficult. The mineral content of plants depends on the amounts present in the soil in which they are grown. Organic foods are cultivated in richer soils, so their mineral content is higher.

But differences are harder to demonstrate for vitamins or antioxidants (plant substances that reduce tissue damage induced by free radicals); higher levels of these nutrients relate more to a food plant's genetic strain or protection from unfavorable conditions after harvesting than to production methods. Still, preliminary studies show benefits: organic peaches and pears contain greater quantities of vitamins C and E, and organic berries and corn contain more antioxidants.

Further research will likely confirm that organic foods contain higher nutrient levels, but it is unclear whether these nutrients would make a measurable improvement in health. All fruits and vegetables contain useful nutrients, albeit in different combinations and concentrations. Eating a variety of food plants is surely more important to health than small differences in the nutrient content of any one food. Organics may be somewhat healthier to eat, but they are far less likely to damage the environment, and that is reason enough to choose them at the supermarket.

Dairy and Calcium
Scientists cannot easily resolve questions about the health effects of dairy foods. Milk has many components, and the health of people who consume milk or dairy foods is influenced by everything else they eat and do. But this area of research is especially controversial because it affects an industry that vigorously promotes dairy products as beneficial and opposes suggestions to the contrary.

Dairy foods contribute about 70 percent of the calcium in American diets. This necessary mineral is a principal constituent of bones, which constantly lose and regain calcium during normal metabolism. Diets must contain enough calcium to replace losses, or else bones become prone to fracture. Experts advise consumption of at least one gram of calcium a day to replace everyday losses. Only dairy foods provide this much calcium without supplementation.

But bones are not just made of calcium; they require the full complement of essential nutrients to maintain strength. Bones are stronger in people who are physically active and who do not smoke cigarettes or drink much alcohol. Studies examining the effects of single nutrients in dairy foods show that some nutritional factors--magnesium, potassium, vitamin D and lactose, for example--promote calcium retention in bones. Others, such as protein, phosphorus and sodium, foster calcium excretion. So bone strength depends more on overall patterns of diet and behavior than simply on calcium intake.

Populations that do not typically consume dairy products appear to exhibit lower rates of bone fracture despite consuming far less calcium than recommended [see sidebar on opposite page]. Why this is so is unclear. Perhaps their diets contain less protein from meat and dairy foods, less sodium from processed foods and less phosphorus from soft drinks, so they retain calcium more effectively. The fact that calcium balance depends on multiple factors could explain why rates of osteoporosis (bone density loss) are highest in countries where people eat the most dairy foods. Further research may clarify such counterintuitive observations.

In the meantime, dairy foods are fine to eat if you like them, but they are not a nutritional requirement. Think of cows: they do not drink milk after weaning, but their bones support bodies weighing 800 pounds or more. Cows feed on grass, and grass contains calcium in small amounts--but those amounts add up. If you eat plenty of fruits, vegetables and whole grains, you can have healthy bones without having to consume dairy foods.

A Meaty Debate
Critics point to meat as the culprit responsible for elevating blood cholesterol, along with raising risks for heart disease, cancer and other conditions. Supporters cite the lack of compelling science to justify such allegations; they emphasize the nutritional benefits of meat protein, vitamins and minerals. Indeed, studies in developing countries demonstrate health improvements when growing children are fed even small amounts of meat.

But because bacteria in a cow's rumen attach hydrogen atoms to unsaturated fatty acids, beef fat is highly saturated--the kind of fat that increases the risk of coronary heart disease. All fats and oils contain some saturated fatty acids, but animal fats, especially those from beef, have more saturated fatty acids than vegetable fats. Nutritionists recommend eating no more than a heaping tablespoon (20 grams) of saturated fatty acids a day. Beef eaters easily meet or exceed this limit. The smallest McDonald's cheeseburger contains 6 grams of saturated fatty acids, but a Hardee's Monster Thickburger has 45 grams.

Why meat might boost cancer risks, however, is a matter of speculation. Scientists began to link meat to cancer in the 1970s, but even after decades of subsequent research they remain unsure if the relevant factor might be fat, saturated fat, protein, carcinogens or something else related to meat. By the late 1990s experts could conclude only that eating beef probably increases the risk of colon and rectal cancers and possibly enhances the odds of acquiring breast, prostate and perhaps other cancers. Faced with this uncertainty, the American Cancer Society suggests selecting leaner cuts, smaller portions and alternatives such as chicken, fish or beans-- steps consistent with today's basic advice about what to eat.

Fish and Heart Disease
Fatty fish are the most important sources of long-chain omega-3 fatty acids. In the early 1970s Danish investigators observed surprisingly low frequencies of heart disease among indigenous populations in Greenland that typically ate fatty fish, seals and whales. The researchers attributed the protective effect to the foods' content of omega-3 fatty acids. Some subsequent studies--but by no means all--confirm this idea.

Because large, fatty fish are likely to have accumulated methyl-mercury and other toxins through predation, however, eating them raises questions about the balance between benefits and risks. Understandably, the fish industry is eager to prove that the health benefits of omega-3s outweigh any risks from eating fish.

Even independent studies on omega-3 fats can be interpreted differently. In 2004 the National Oceanic and Atmospheric Administration--for fish, the agency equivalent to the USDA--asked the Institute of Medicine (IOM) to review studies of the benefits and-risks of consuming seafood. The ensuing review of the research on heart disease risk illustrates the challenge such work poses for interpretation.

The IOM's October 2006 report concluded that eating seafood reduces the risk of heart disease but judged the studies too inconsistent to decide if omega-3 fats were responsible. In contrast, investigators from the Harvard School of Public Health published a much more positive report in the Journal of the American Medical Association that same month. Even modest consumption of fish omega-3s, they stated, would cut coronary deaths by 36 percent and total mortality by 17 percent, meaning that not eating fish would constitute a health risk.

Differences in interpretation explain how distinguished scientists could arrive at such different conclusions after considering the same studies. The two groups, for example, had conflicting views of earlier work published in March 2006 in the British Medical journal. That study found no overall effect of omega-3s on heart disease risk or mortality, although a subset of the original studies displayed a 14 percent reduction in total mortality that did not reach statistical significance. The IOM team interpreted the "nonsignificant" result as evidence for the need for caution, whereas the Harvard group saw the data as consistent with studies reporting the benefits of omega-3s. When studies present inconsistent results, both interpretations are plausible. I favor caution in such situations, but not everyone agrees.

Because findings are inconsistent, so is dietary advice about eating fish. The American Heart Association recommends that adults eat fatty fish at least twice a week, but U.S. dietary guidelines say: "Limited evidence suggests an association between consumption of fatty acids in fish and reduced risks of mortality from cardiovascular disease for the general population … however, more research is needed." Whether or not fish uniquely protects against heart disease, seafood is a delicious source of many nutrients, and two small servings per week of the less predatory classes of fish are unlikely to cause harm.

Sodas and Obesity
Sugars and corn sweeteners account for a large fraction of the calories in many supermarket foods, and virtually all the calories in drinks-- soft, sports and juice--come from added sugars. In a trend that correlates closely with rising rates of obesity, daily per capita consumption of sweetened beverages has grown by about 200 calories since the early 1980s. Although common sense suggests that this increase might have something to do with weight gain, beverage makers argue that studies cannot prove that sugary drinks alone--independent of calories or other foods in the diet--boost the risk of obesity. The evidence, they say correctly, is circumstantial. But pediatricians often see obese children in their practices who consume more than 1,000 calories a day from sweetened drinks alone, and several studies indicate that children who habitually consume sugary beverages take in more calories and weigh more than those who do not.

Nevertheless, the effects of sweetened drinks on obesity continue to be subject to interpretation. In 2006, for example, a systematic review funded by independent sources found sweetened drinks to promote obesity in both children and adults. But a review that same year sponsored in part by a beverage trade association concluded that soft drinks have no special role in obesity. The industry-funded researchers criticized existing studies as being short-term and inconclusive, and pointed to studies finding that people lose weight when they substitute sweetened drinks for their usual meals.

These differences imply the need to scrutinize food industry sponsorship of research itself. Although many researchers are offended by suggestions that funding support might affect the way they design or interpret studies, systematic analyses say otherwise. In 2007 investigators classified studies of the effects of sweetened and other beverages on health according to who had sponsored them. Industry-supported studies were more likely to yield results favorable to the sponsor than those funded by independent sources. Even though scientists may not be able to prove that sweetened drinks cause obesity, it makes sense for anyone interested in losing weight to consume less of them. The examples I have discussed illustrate why nutrition science seems so controversial. Without improved methods to ensure compliance with dietary regimens, research debates are likely to rage unabated. Opposing points of view and the focus of studies and food advertising on single nutrients rather than on dietary patterns continue to fuel these disputes. While we wait for investigators to find better ways to study nutrition and health, my approach--eat less, move more, eat a largely plant-based diet, and avoid eating too much junk food--makes sense and leaves you plenty of opportunity to enjoy your dinner.

OLD ADVICE STILL HOLDS TRUE
In 1959 Ancel and Margaret Keys offered the following--familiar and still useful--precepts regarding nutrition and activity:


• Do not get fat; if you are fat, reduce.


• Restrict saturated fats: fats in beef, pork, lamb, sausages, margarine and solid shortenings; fats in dairy products.


• Prefer vegetable oils to solid fats but keep total fats under 30 percent of your diet calories.


• Favor fresh vegetables, fruits and nonfat milk products.


• Avoid heavy use of salt and refined sugar.


• Good diets do not depend on drugs and fancy preparations.


• Get plenty of exercise and outdoor recreation.



FOOD FACTOIDS


• To reduce your weight by a pound of fat a week, eat 500 fewer calories each day.


• Carbohydrates and proteins have about 4 calories per gram. Food fats contain more than twice as much: 9 calories per gram. A teaspoon holds about 5 grams.


• Alcohol is metabolized in a way that promotes accumulation of fat in the liver, leading to the proverbial beer belly.


• An adult expends about 100 calories for every mile walked or run. It takes nearly three miles to burn off the calories in a 20-ounce soft drink.

NOT MILK?
Surprisingly, some populations that eat few calcium-rich milk products appear in some descriptive studies to have lower rates of hip fractures than others that consume large quantities of dairy foods, despite the fact that diets of the former group contain far less calcium than experts recommend. This observation has not been fully explained.

AS FOOD CALORIES SWELL, SO DO WAISTLINES
OBESITY GAINS A substantial rise in U.S. obesity rates during the past few decades was paralleled by increases in the availability of larger portion sizes, total calories, caloric sweeteners and sugary soft drinks in the food supply. The apparent dip in three of these measures (calories, sugars and sugary soft drinks) after 1998 may be explained by greater use of artificial sweeteners and the partial replacement of sugary soft drinks with beverages that are not sweetened with sugars.

U.S. OBESITY RATES ON THE RISE
1976-1990 15.1%
1988-1994 23.3%
1999-2000 31.0%
2001-2002 32.1%
2003-2004 33.9%

SUPER-SIZE PORTIONS GROW
Number of food items introduced in larger sizes by restaurants and manufacturers in the U.S.

1975-1979 6
1980-1984 12
1985-1989 36
1990-1994 47
1995-1999 63

pwd

In response to the reference to the article questioning the link between fat and heart disease, Rob Grant wrote a novel called FAT where he argues the same thing (that the apparent link between fat and heart disease is not necessarily correct). It's a good book.

"Willett says. "If they go up over a BMI of 30, they've increased their risk of diabetes 30- to 60-fold," he says.. "And diabetes is not a good thing to have.""

- This is overly simplistic I think. As far as I know, adult onset diabetes is caused essentially by eating too much simple carbohydrate, because simple carbohydrate causes changes in insulin levels. Eating large amounts of simple carbohydrates is likely to make you fat and therefore may give you a BMI of 30, and also probably increases your risk of diabetes, but being fat, or having a bmi of 30, does not necessarily equate to having eaten lots of simple carbs, and therefore may not indicate an increased risk.

nesf

g'em wrote:

will I be breaking a gazillion copywrite laws if I put up some of the articles here?

Pretty much, yes.

g'em

nesf wrote:

Pretty much, yes.

Woohoo!! I like living on the edge so I does

g'em

pwd wrote:

"Willett says. "If they go up over a BMI of 30, they've increased their risk of diabetes 30- to 60-fold," he says.. "And diabetes is not a good thing to have.""

- This is overly simplistic I think. As far as I know, adult onset diabetes is caused essentially by eating too much simple carbohydrate, because simple carbohydrate causes changes in insulin levels. Eating large amounts of simple carbohydrates is likely to make you fat and therefore may give you a BMI of 30, and also probably increases your risk of diabetes, but being fat, or having a bmi of 30, does not necessarily equate to having eaten lots of simple carbs, and therefore may not indicate an increased risk.

It is an extremely simplistic view on things, but I don't think it's inherently wrong. Adult onset diabetes (Type II or Diabetes mellitus) isn't just caused by eating too many simple carbs, there's a whole host of risk factors, the most prominent of which are the family history, genetics, a sedentary lifestyle, poor diet (generally consisting, as you say, of a large amount of refined carbs) and high blood pressure.

But being overweight, and more specifically carrying excess fat abdominally, is teh one over-riding commonality among those diagnosed with Type II diabetes. It's not the single cause of it, but it's a huge factor, so I'd be inclined to beleive that being fat really does increase your risk that much.

And it's true that having a BMI > 30 doesn't automatically equate to a diet high in refined carbs, but those with a BMI > 30 and/or a sedentary lifestyle and/or a family history of diabetes and/or excess abdominal adipose and/or high blood pressure etc. etc. are also those people who are more likely to have got to that stage from eating badly.

ali.c

g'em wrote:

And it's true that having a BMI > 30 doesn't automatically equate to a diet high in refined carbs, but those with a BMI > 30 and/or a sedentary lifestyle and/or a family history of diabetes and/or excess abdominal adipose and/or high blood pressure etc. etc. are also those people who are more likely to have got to that stage from eating badly.

Tbh, i thought the article was going to be alot more interesting than it was. primarly as when they are talking about "fit" overweight people which isnt really mentioned at all in the article. Also the stuff that g'em is saying there is dead on, but no "fit" people i know lead a sedentary lifestyle. I think the BMI scale is fine as a statisical tool, but since the are apparantely discussing the article entitled "can fat be fit" and not considering the possiblity that that an overweight or even obese "BMI" can have an average or indeed low body fat is utter crap IMHO. I was expecting some discussion on people who are overweight (in a fat sense) but active and was interested to see if there was any conclusion on whether this impacted on health or not.

nesf

ali.c wrote:

Tbh, i thought the article was going to be alot more interesting than it was. primarly as when they are talking about "fit" overweight people which isnt really mentioned at all in the article.

It's interesting in that it's a rebuttal (or more accurately a report of the rebuttal) of the oft quoted report showing people with BMIs of 25-30 having a lower mortality rate.

It would be very interesting if someone did a study on the different groups that make up each of the strata but I haven't seen anything like that mentioned anywhere. One combining frame size and BMI would be very interesting, you could take two guys who are 6 foot, one with a narrow frame and the other with a broad frame and even though their BMI number might be identical their prognoses might be quite different.