5
DIET AND NUTRITION



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Headline News Science Views II 5 DIET AND NUTRITION

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Headline News Science Views II This page in the original is blank.

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Headline News Science Views II Weight Control: What Really Works Judith S. Stern The next time you see a commercial in which celebrities extol a diet program, be skeptical as to whether their personal success proves the effectiveness of the program for others. A panel of the National Institutes of Health reported ear-her this year that commercial diet programs have extremely low rates of long-term success. Ninety percent or more of the people who enroll in them regain all or most of their hard-lost pounds within five years. That may sound like bad news for the millions of people in the United States — more than a third of the women and nearly a quarter of the men — who are trying to lose weight. An even larger number of Americans seek to maintain their weight. If commercial diet programs have such limited success rates, what possibility does anyone have of succeeding? People would have a greater chance if they paid more attention to scientific findings and less to advertising claims. Many Americans worry needlessly about their weight, persuaded incorrectly that they are too fat. They even may harm themselves if they repeatedly lose weight and then gain it back. But those who really need to take off some pounds should not become discouraged. The fact is that some people do lose weight and keep it off. Why are they successful while others keep yo-yoing through weight changes?

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Headline News Science Views II Much of the answer can be found in what we have begun to learn about successful "maintainers," data discussed recently at a meeting of the Food and Nutrition Board of the National Academy of Sciences' Institute of Medicine. I was part of a research project that studied three groups of women. The first group included women who never had a weight problem. Women in the second group lost weight and kept it off for at least two years. The third group was comprised of women who lost weight only to regain it. The women in the first two groups shared several characteristics. They generally exercised regularly and ate foods lower in fat and sugar. Both of these findings make sense. Many research studies demonstrate that exercise helps people maintain lower weights. Experimental animals that exercise are much more likely than their "couch potato" counterparts to choose a low-fat diet. Calories from fat, meanwhile, are more likely to make people gain weight than calories from carbohydrates. In animals, a combination of fat and sugar is more fattening than fat and sugar eaten separately. Exercising regularly and cutting back on fat and sugar are not the only successful weight control techniques that we identified in controlled studies. Women who never were overweight or who kept excess weight off successfully weighed themselves regularly. They were more likely to have good problem-solving skills and to confront difficulties directly rather than avoiding them. In addition, these maintainers usually had good social support networks with friends and family available to help them deal with everyday problems. Emerging research also reveals interesting differences in how unsuccessful "regainers" and successful maintainers pursue their diets. Those who regain weight are more likely to follow doctor's orders and structured diet plans. In contrast, maintainers tend to follow a diet program they devise themselves to suit their own lifestyles. They take control and are "in the driver's seat." Scientists still do not know the basic cause of many obesities. Even though Americans are obsessed with dieting, much of the research needed to provide more rational treatments has not yet been performed. Nonetheless, completed studies do

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Headline News Science Views II suggest that women who seek to lose weight should choose an individual program tailored to their own needs, modify their food choices and be physically active. To keep the weight off, they also must learn effective problem-solving techniques. Admittedly, these skills are not easy to master. One of the most encouraging things we have learned is that people often need not lose much weight to enjoy significant health benefits. Losing as little as 5 percent to 10 percent of body weight can bring about improvements in blood pressure, diabetes and blood lipids. In other words, for those who truly are overweight, making a change is well worth the effort. But the change needs to be based on science rather than on celebrity endorsements. August 2, 1992 Judith S. Stern is professor of nutrition and internal medicine at the University of California, Davis. * * * Serving Up Nutrition Instead of Guilt Edward N. Brandt Jr. and Paul R. Thomas Trying to eat a healthful diet these days is no piece of cake. It's little wonder so many Americans don't eat as well as they should. Many people do try to limit certain foods or to improve nutrition for their children. But anyone who has ever flinched at the bathroom scale or examined the wares at the local supermarket knows how demanding it can be to maintain a healthful diet. If cars crashed hourly at an intersection, we'd redesign the intersection rather than blame all of the drivers. Yet we

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Headline News Science Views II Drawing by David Kiphuth The Daily Gazette, Schenectady, N.Y. tend to view the eating problems of countless Americans as signs of personal weakness rather than of something awry with the broader situation. Throughout the United States, per capita consumption of fresh fruits and vegetables, breakfast cereals and low-fat milk has increased. Many consumers report using less salt and fat in their foods. However, people also are eating more high-fat cheeses and frozen desserts, fats and oils, snack foods and candy. Perhaps consumers are being too hard on themselves in viewing such lapses as personal failures. The path to better nutrition is hindered by too many barriers, from fast foods loaded with saturated fat to incomplete labels on packaged foods. Surveys indicate that many people lack both the information and skills to eat better. What they need is not guilt but more help.

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Headline News Science Views II Thanks to continuing efforts by government, the food industry, health care providers and educators, it's easier than ever to eat well. The recent work of the federal government to develop better food labels, for example, could do a great deal to promote better nutrition. Yet it is possible to do more — much more. We served on a committee of the Institute of Medicine of the National Academy of Sciences that recently identified numerous ways to make things easier for eaters. Supermarkets, for example, could provide nutritional information at points of purchase, such as with signs in the produce or dairy aisles, or with tags indicating that certain products are a good nutritional buy. Restaurants could provide nutritional analyses of their menu items. Educators could help Americans make sense of this information, teaching pre-schoolers good eating habits along with their A-B-Cs and providing their older brothers and sisters with nutrition education throughout their schooling. Company cafeterias, television shows and others could promote nutrition education more informally. Just as television producers have reduced the gratuitous use of alcohol and drugs on many programs, so might characters begin eating healthier foods. On the show ''Cheers,'' for example, why not have Norm eat something healthier than beer nuts? Informal efforts are especially important for changing eating patterns among less educated and poorer Americans, who generally have worse diets. Then there is government, which has tremendous leverage to encourage better nutrition through the School Lunch Program, farm subsidies and a host of other initiatives. At the very least, facilities such as public hospitals and government agency headquarters should provide good foods in their own cafeterias and kitchens. Consumers who shop carefully in supermarkets generally can put together a healthful diet, and food producers have improved the content of many items by cutting back on the fat, salt and sugar. Yet consumers also need access to nutritious foods elsewhere. For many people, "dinner" means a stop at a fast-food restaurant or a microwaved frozen entree rather than a home-cooked meal. Instead of gorging on fat,

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Headline News Science Views II they should be able to eat a healthful meal with a minimum of bother. Consumers need help not only from restaurants and food producers, but from government, health care providers and everyone else involved with food in our country. Of course, we still must take responsibility for what we eat. But it should not be so difficult or confusing to eat wisely. As matters now stand, our national diet is too high in guilt and too low in practical information and healthful choices. Rather than blaming people for failing to overcome the situation, it's time to cook up something better. July 14, 1991 Edward N. Brandt Jr., executive dean of the Health Sciences Center at the University of Oklahoma, Oklahoma City, chaired a committee of the Institute of Medicine of the National Academy of Sciences that examined the nation's diet and health. Paul R. Thomas was the committee's study director. * * * The Foods in Our Future Sanford A. Miller Dieting baseball managers and talk show hosts get the publicity, but a quiet revolution now gaining momentum within the scientific world could change the way people lose weight — and much more. It could lower the risk of heart attacks, alleviate hunger and transform agriculture. Breakthroughs in molecular biology and other disciplines are about to change the way we Americans produce, eat and think about food. These changes could yield great benefits. They also pose challenging social and scientific questions that warrant much more attention. Scientists are beginning to use genetic engineering and

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Headline News Science Views II other tools to design foods with incredible precision. In the past, agricultural scientists developed more bountiful crops and healthier animals through traditional breeding — a slow, almost random process. But now researchers are speeding up and refining this process, like carpenters using power tools after centuries of working by hand. The fruits — and vegetables — of their efforts are emerging in the form of fat substitutes, substitute lobster meat, crops with higher nutritive value and animals more resistant to disease. Other exciting foods with new shapes, colors and flavors are on the way. Before long, consumers could see foods made from fungi and other non-traditional materials — tasting like meat but more nutritious. Foods will have their genes reshuffled to produce desirable characteristics, such as fresh tomatoes in winter that actually taste like tomatoes right off the vine, and grains that thrive in drought-ridden areas of Africa. Changes like these, when combined with progress in nutrition and other scientific fields, could improve the quality of life significantly. Yet, like any advance, they may cause harm if not implemented rationally. A recent conference of the Institute of Medicine of the National Academy of Sciences considered some of these problems. The public outcry over the introduction of milk derived from animals treated with bovine somatotrophin (BST), and about using ionizing radiation to process food, shows that new food technologies can arouse considerable public fear. While most scientists agree that these technologies are safe, the controversy about them illustrates that any advance must be as acceptable socially and economically as it is scientifically. One specific problem that could arise with new foods is the possibility of varied products being made from a diminishing number of raw materials, such as from soy beans. People need to eat a wide array of foods. Yet some companies may find it cheaper and technologically easier in the future to create look-alike foods from a few raw materials. For instance, they might create substitutes for beef, poultry or fish. Consumers might suffer nutritional imbalances if the foods were not carefully enriched.

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Headline News Science Views II With more efficient technologies, companies also may use fewer processing plants. This should yield cost savings and make the businesses more competitive, which helps our economy, but it could cost some workers their jobs. Increased consolidation also means that problems at any plant — such as an outbreak of food contamination — may affect more consumers. The techniques used within the plants pose still other problems. Fermentation methods, for example, are likely to be used increasingly to produce everything from abalone substitutes to vitamins. Millions of consumers will enjoy these products. But fermentation also will produce waste materials that typically contain a large number of living microorganisms and organic materials. Methods will be needed to dispose of these wastes safely, perhaps by sterilizing them and converting them into animal feed or fertilizer. Then there are international concerns. New food technologies are likely to be alluring to developing countries where hunger is common. Providing nutritious and hardy new foods for Ethiopia, for example, would be a major scientific accomplishment. Yet poor countries also will need help in regulating these advances to prevent abuses and to assure the safety and quality of their food. As one involved in evaluating new foods, I think the benefits are likely to vastly outweigh these and other potential problems. Both the scientific community and public officials are considering these questions now to ensure that our food supply remains healthy, safe and economical in the years ahead. And if we plan carefully, the foods emerging from our laboratories should bring us everything from better nutrition to lower grocery bills. If we don't, however, tomorrow's menu may not be to everyone's liking. March 31, 1991 Sanford A. Miller is professor and dean of the Graduate School of Biomedical Sciences at the University of Texas Health Science Center at San Antonio. * * *

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Headline News Science Views II Improving the Safety of Seafood John Liston Few feelings are worse than eating some oysters, clams or other seafood and then, a few hours later, becoming sick with nausea and diarrhea. Fortunately, most seafood sold to the public is wholesome and unlikely to cause illness if properly prepared. But Americans are eating a lot more seafood than they did just a decade ago, so the importance of ensuring a safe supply has intensified. I chaired a committee of the Institute of Medicine of the National Academy of Sciences that recently examined seafood safety. We found that seafood generally deserves its reputation as a healthy food. The number of reported cases of seafood-borne illness has remained fairly low despite increased consumption. Yet seafood safety can be strengthened. This is best done by preventing sewage, hazardous chemicals and other contaminants from entering the waters where shellfish and finfish are caught. The cleaner the water, the safer the fish are likely to be. Unfortunately, cleaning our fishing waters will take years and even then will not put an end to problems due to naturally occurring bacteria or marine toxins. So other actions are needed now. What's not needed is a lot of new inspectors sniffing and probing individual fish before they are sold. This would be terribly costly and essentially worthless for detecting or controlling health risks. The biggest single risk associated with eating seafood is from raw oysters, clams, mussels and other "bivalve molluscs," which may cause hepatitis and other problems if contaminated or mishandled. Raw shellfish is especially risky for people with liver disease or weakened immune systems. Health officials should do more to warn the public about this danger, and consumers always should cook seafood thoroughly. A quite different kind of problem, and one that cannot be

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Headline News Science Views II eased by adequate cooking, is fish contaminated with natural toxins. For example, fish caught near reefs in tropical areas may contain a toxin that causes ciguatera, a particularly nasty kind of food poisoning. The best way to prevent ciguatera is by banning certain fish species or fish caught in suspect areas, and by developing tests to identify toxic fish. Then there are toxic chemicals such as PCBs or dioxin, which can accumulate in aquatic animals. Evaluating chemical health risks often is difficult since the effects — such as an increase in cancer — may be slow to appear and hard to attribute to a single cause. But the threat can be reduced by restricting harvests from polluted waters. Supervision is done most effectively on the state and local level since problems vary so widely from place to place. While consumers in Puerto Rico worry about ciguatera, for example, those on the mainland may be more concerned about a milder form of poisoning in fresh and frozen species like tuna or bluefish. In Alaska, botulism can occur in some traditional fermented seafood. Consumers are now protected, although inadequately, by an intricate system of federal and state programs. Inspectors at all levels focus too much on the "finished products" — the fish in the store — rather than on the raw materials in the water. The most important federal role should be to provide guidance and technical assistance and, since imported seafood accounts for more than half of U.S. consumption, to monitor the inspection procedures of foreign countries. Local officials, meanwhile, need better enforcement measures to prevent "bootlegged" shellfish from hazardous areas from reaching the market. They also might restrict harvests of some shellfish during warmer weather, when the threat of food poisoning is greatest. Scientists and other technical experts can help, too, by providing more effective methods of testing whether waters or individual fish are contaminated. A simple test to screen fish for ciguatera has been developed but needs more examination. Improved tests for viruses could help protect shellfish waters. Better technology and education are needed to

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Headline News Science Views II improve safety for the millions of Americans who fish for sport or daily subsistence. Despite these concerns, seafood remains one of the safest and healthiest foods consumers can eat, whether in a fresh salmon steak, trout almondine or a tuna sandwich. But with more and more Americans eating seafood, safety now needs to become as inseparable from their meals as the lemon slices and tartar sauce. January 27, 1991 John Liston is professor emeritus of the Institute for Food Science and Technology at the University of Washington in Seattle. * * * Fighting Trim, Fighting Smart Robert O. Nesheim An old adage states that an army travels on its stomach. But Army standards say too much stomach is unacceptable; soldiers who get fat risk being dismissed. Requiring soldiers to be in "fighting trim," as currently defined, is of increasingly dubious value in an age when success on the battlefield depends as much on programming computers as on charging up a hill. Dismissing a brilliant computer programmer because he or she is somewhat overweight does not make any more sense for the military than it would in academic or business situations. Not that the military should disregard the physical condition of its troops. But it does need to find a better match between its weight standards and people's ability to perform military tasks. I recently chaired a committee of the Institute of Medi-

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Headline News Science Views II cine of the National Academy of Sciences that examined the Army's standards and found them in need of updating. Good people may be forced out of the military or deterred from joining because their physiques fail to measure up to an ideal of questionable relevance. The Army recently revised its weight standards to ease a disparity that was especially unfair to women. Females had been allowed less variation over their prescribed standards than their male counterparts were allowed over their standards. Racial and ethnic groups also have diverse body types that may differ from norms established by years of studies of Caucasian males. Making the standards more equitable among the diverse members of the military is commendable. But changes still are needed in the system as a whole. According to Army regulations, a six-foot male recruit, 17 to 20 years old, should weigh no more than 200 pounds. A five-foot, five-inch woman of the same age should weigh no more than 141 pounds. If the recruit weighs more, the Army then determines the proportion of body fat through a number of different procedures. Once admitted to the military, personnel must meet even more stringent retention standards. Both recruits and service personnel also must meet fitness standards that include push-ups, sit-ups, running and similar exercises. Seemingly sensible, these measures do not test directly what the Army really needs to know, which is whether someone can do the job. Smaller, lighter individuals who do well in running and physical fitness tests may perform poorly on tasks such as lifting and load-carrying. A moderately overweight person, by contrast, may be better at pitching tents for hurricane victims in Florida, carrying loads in the Persian Gulf or other tasks, not to mention jobs done at a desk. Our committee concluded there is no consistent relationship between body fat content and physically demanding jobs. Lean body mass (muscle and bone) is a much better predictor than body fat of physical performance. The services should consider establishing minimum standards for lean

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Headline News Science Views II body mass and also should develop specific standard tests that more accurately reflect military activities. Currently the military standards primarily involve height and weight. As a result, healthy individuals who are very muscular, such as professional football players, may be rejected for being too heavy. Does all this mean the military should not be concerned about excess weight or military appearance? Of course not. About 20 percent of the U.S. population is overweight and obese, and there is a proven correlation between obesity and diverse health problems. The armed services, which provide medical care for millions of employees and retirees, have a legitimate interest in minimizing these costly problems. Furthermore, for purposes of public image and unit morale, the services have a right to expect a reasonably trim military appearance among those in uniform. But holding down health care costs and keeping soldiers looking sharp does not require height-weight standards as stringent as those now on the books. Revising these standards would not open the door to poor discipline and ranks filled with potbellies. Rather, they would reflect modern understanding of body composition and physical performance. As the military faces severe budget cutbacks, it must not squander the years of training it has invested in valuable personnel, based on out-of date standards. September 20, 1992 Robert O. Nesheim is retired vice president for science and technology at Quaker Oats Co.

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