A look at how Americans' eating habits -- and the dietary advice we've received -- have changed over the years.
Americans advised to eat more
Dietary advice during this period is mostly targeted to persuade Americans to eat more nutrients and to consume from the full range of American agricultural products.
The earliest studies from the United States Department of Agriculture (USDA) suggest that a balanced diet should contain 15 percent of calories from protein, 33 percent from fat and 52 percent from carbohydrates.
In 1917, the USDA releases a pamphlet "How to Select Foods," which contains its first set of dietary recommendations. The document organizes food into five categories -- fruits and vegetables, meats and other proteins, cereals and other starches, sweets, and fatty foods -- which set the standard food groups that the USDA still uses.
Pioneering research on diet and heart disease
Dr. Ancel Keys, a physician at the University of Minnesota and a pioneer in the study of heart disease, launches the Seven Countries Study, which surveys men in Finland, Greece, Yugoslavia, Italy, Netherlands, Japan and the U.S. and concludes that heart disease correlates with diet and exercise. He also finds that in countries where people don't eat as much fat, heart disease rates are lower.
Keys and other scientists begin to argue that Americans are eating too much animal fat. Their theory is that this contributes to high cholesterol levels which contribute to heart disease.
Weight Watchers is founded
The group is founded by housewife Jean Nidetch of Queens, N.Y. She invites her friends over weekly to discuss how best to lose weight. The group now estimates it has 1 million members worldwide.
McGovern committee established to fight war against hunger
After CBS airs a 1967 documentary, "Hunger in America," about malnutrition and hunger among the poor, there is a public outcry for greater federal food assistance programs. Sen. George McGovern (D-S.D.) is chosen to lead a Senate Select Committee on Nutrition and Human Needs. His committee, which meets for nine years, creates the food stamp and other federal assistance programs.
The McGovern committee also takes notice of the research emerging from Ancel Keys and others and gradually switches its focus to "over-nutrition," or dietary excesses, in the mid-1970s. It holds hearings in 1973, 1974 and 1976 on the relationship between diet and diseases including cancer, diabetes and heart disease.
Dr. Atkins' Diet Revolution published
Atkins recommends eating a diet high in protein and fat and low in carbohydrates. He argues that in reducing carbohydrates, the body will burn excess fat for fuel and that the diet's adherents will feel satiated. Although the book is a bestseller, the Atkins diet is considered outside of the medical mainstream for the next 30 years.
Nurses' Health Study Begins
Dr. Frank Speitzer establishes the Nurses' Health Study to examine the long-term use of contraceptives. The study tracks 122,000 registered nurses, who fill out detailed surveys every two years about their diet and health. It is one of the only long-term studies to track the relationship between nutrition and disease and a second investigation is started in 1989 to target a younger population.
Among the findings of the Nurses Health Study is a relationship between increases in body mass index (a measure of body fat) and increased risk of heart disease, high blood pressure, gallstones and type 2 diabetes.
Controversy over "Dietary Goals for the United States"
The McGovern committee releases a document "Dietary Goals for the United States," based on its mid-1970s hearings. The report, which recommends Americans increase carbohydrate consumption, but decrease fat, saturated fat, cholesterol, sugar and salt consumption, immediately causes a stir. Members of the food industry who would be directly affected -- including cattle, egg, sugar and dairy producers -- insist the report be revised. Scientists also protest that the recommendations are based on unproven science.
The committee responds by holding follow-up hearings and a second report is published later in the year. The revised version allows for increased salt and egg consumption and changes the advice from "reduce consumption of meat" to "choose meats, poultry, and fish which will reduce saturated fat intake."
Pritikin Program for Diet & Exercise published
Nathan Pritikin and his son Robert develops the Pritikin Longevity Center and its strict low-fat diet and exercise program in response to Pritikin's belief that such a regimen reversed his own heart disease.
"Dietary Guidelines for Americans" issued
The USDA and the Department of Health and Human Services (DHHS) jointly release the "Dietary Guidelines for Americans." The document's recommendations include: "Eat a variety of foods; Maintain ideal weight; Avoid too much fat, saturated fat and cholesterol; Eat foods with adequate starch and fiber; Avoid too much sugar; Avoid too much sodium; If you drink alcohol, do so in moderation." Because the guidelines do not recommend reducing intake of any particular food, they prove to be much less controversial than the McGovern committee's "Dietary Goals."
America's obesity epidemic begins
During the 1960s and 1970s, 13 to 14 percent of Americans are classified as obese. However, during the 1980s, that number rises by 8 percentage points and it continues to rise throughout the 1990s. Currently, one-third of the American population is considered to be obese.
View a series of maps from the Centers for Disease Control (CDC) that show the growth of the American obesity epidemic from 1985 to 2002.
Low-fat dietary recommendations continue
During this period, numerous scientific studies -- including a study of meat commissioned by the American Meat Institute, the National Cattlemen's Association and the National Pork Producers Council and the "Surgeon General's Report on Nutrition and Health" -- confirm the need for Americans to reduce the amount of fat in their diet. Groups including the American Heart Association, the National Heart, Lung, and Blood Institute and other advocacy organizations also issue recommendations to lower fat intake to fight conditions including cancer, diabetes, high blood pressure and heart disease.
USDA publishes food pyramid
The food pyramid is scheduled to be released in 1991 but is withdrawn after pressure from meat and dairy producers who are upset over its recommendations. A storm of controversy ensues over the perception of corporate favoritism on behalf of the USDA, although Agriculture Secretary Edward Madigan maintains that he blocked the pyramid's release because it would confuse children.
The pyramid is released in April 1992 after a year of evaluation by the USDA. The bread, cereal, rice and pasta group forms the base of the pyramid, which recommends Americans eat six to 11 servings from this group each day. The next level suggests three to five servings of vegetables and two to four servings of fruits per day; followed by two to three servings each from the "milk, yogurt and cheese group" and the "meat, poultry, fish, dry beans, eggs, and nuts group." At the top of the pyramid is fats, oils and sweets, which are to be used sparingly.
In recent years, critics have suggested that Americans' wide recognition of the food pyramid during the 1990s may correlate with the nation's obesity problem because of the pyramid's recommendation that carbohydrates should be the foundation of healthy eating habits. Read what FRONTLINE's experts believe about the need to reassess the food pyramid.
Dr. Atkins' New Diet Revolution published
In 1992, Atkins publishes an updated version of his diet and during the mid-1990s, the Atkins diet takes off. In 1998, he forms Atkins Nutritionals to sell food products created for his followers and revenues from the company reportedly reach $100 million. By 1999, four other high-protein diet books -- Sugar Busters!, Protein Power, Eat Great, Lose Weight and The Zone -- join Atkins on the bestseller list.
Eat More, Weigh Less published
During the height of the low-fat era cardiologist Dr. Dean Ornish, the author of Eat More, Weigh Less recommends a low-fat, plant-based diet to protect against heart disease and other medical conditions. Ornish also recommends meditation and support groups as part of a wellness regimen.
Diet wars heat up at USDA conference
In February, Agriculture Secretary Dan Glickman and the USDA sponsor The Great Nutrition Debate to try and clear up public confusion regarding diet advice. Dr. Atkins and Dr. Ornish are among the participants at the conference. The participants agree that Americans need to lose weight and that they should exercise and avoid sugar. Beyond that, the debate is contentious. "There was no consensus," Glickman says. "I recall that Dr. Atkins and Dr. Ornish just about went at each other physically. It was amusing to me, but I don't know if it was edifying to the people who buy books and try to find ways to lose weight."
Eat, Drink and Be Healthy published
Harvard nutritionist Dr. Walter Willett, who launched the second phase of the Nurses Health Study in 1989, publishes Eat, Drink and Be Healthy to explain why he believes the USDA food pyramid recommendations are wrong and potentially dangerous. He argues that the USDA food pyramid is based on "shaky scientific ground" and that it does not recognize the difference between "good" and "bad" fats and carbs.
Willett offers his version of a revised food pyramid with daily exercise and weight control at the base. He recommends whole grain foods and plant-based oils (such as olive, canola, corn and other vegetable oils) at every meal; vegetables "in abundance;" two to three daily servings of fruit; one to three daily servings of nuts and legumes; up to two daily servings of fish, poultry and eggs; and one to two daily servings of dairy or calcium supplements. At the top of Willett's pyramid are "red meat, and butter" and "white rice, white bread, potatoes, pasta and sweets," which are to be used sparingly.
The South Beach Diet published
As the low-carb trend heats up, The South Beach Diet by Florida cardiologist Dr. Arthur Agatston is published. Agatston, who maintains his diet is not a low-carb diet, but rather a diet that "teaches you to rely on the right carbs and the right fats," develops the diet after he becomes disillusioned with watching his patients fail to lose weight and reverse heart disease on low-fat regimens.
Revised food pyramid expected to be published
Sources: Food Politics: How the Food Industry Influences Nutrition and Health, Marion Nestle (University of California Press, 2003); "What If It's All Been a Big Fat Lie?" (The New York Times Magazine, July 7, 2002); and news reports