Wednesday, January 27, 2021

Walter Willett


– the professor who saw the light

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WALTER WILLETT, Professor of Epidemiology and Nutrition, Chairman of the Department of Nutrition at the Harvard School of Public Health, and Professor of Medicine at Harvard Medical School, used to advise consumers to switch from butter to margarine.

In a PBS television interview on 9 January 2004, Walter Willett admitted:

Unfortunately, as a physician back in the 1980s, I was telling people that they should replace butter with margarine because it was cholesterol free, and professional organizations like the American Heart Association were telling us as physicians that we should be promoting this.

In reality, there was never any evidence that these margarines, that were high in trans fat, were any better than butter, and as it turned out, they were actually far worse than butter.

Today, Walter Willett is one of America’s most active and influencial campaigners against margarine and other products containing trans fats. He is probably also the most widely quoted.

In recent months, whenever press reports carried news about trans fats, those reports almost inevitably quoted Walter Willett saying…

Trans fats cause at least 30,000 deaths from heart disease in the US each year – and that the actual figure could be as high as over 100,000.

The figure came from his research findings published in 1997, which led Willett to remark that trans fats represent “the biggest food processing disaster in U.S. history.”

Trans fat labelling and ban

This piece of statistic had a major bearing on the decision by the US Food and Drug Administration to introduce new legislation requiring trans fat labelling on the nutrition facts labels. That trans fat labelling law was announced in 2003 and it took effect on 1 January 2006.

The same piece of statistic also influenced the New York City Board of Health to propose a ban on trans fats on 26 September 2006. Ten weeks later, on 5 December, members of the New York City Board of health voted unanimously to approve the ban.

So starting 1 July 2007, restaurants in New York will not be allowed to use or serve trans-fat-laden oils, shortenings and spreads like margarine. And by 1 July 2008, bakeries and restaurants will have to replace trans fats in baked goods and deep-fried desserts.

With New York taking the lead, the rest of America is expected to follow. Los Angeles, Boston, Philadelphia, Chicago and Seattle (plus the whole of Washington State) are, as of January 2007, among those considering a ban, or at least some form of curb, on the use of trans fats.

This is certainly something that Walter Willett would like to see. He is currently campaigning for hydrogenated vegetable oils – the main source of trans fats in the modern diet – to be removed from the GRAS (generally recognised as safe) list administered by the FDA.

The FDA had, in 1976, granted GRAS status to hydrogenated soybean oil. It bowed to pressure from the vegetable oils industry and relied on the industry’s false assurances at that time that trans fats posed no health dangers.

Linus Pauling Institute Prize

Walter Willett is one of the most productive medical and health researchers of modern times, having published over 700 scientific papers as well as a popular book, Eat, Drink and Be Healthy.

On 23 May 2003, he was awarded the Linus Pauling Institute Prize for Health Research, which recognises excellence in the field of orthomolecular medicine, especially in the study of micronutrients, vitamins, and phytochemicals in promoting optimal health and in the prevention and treatment of disease.

The recipient of the first Linus Pauling Institute Prize in 2001, Dr Bruce Ames, praised Dr Walter Willett for his productivity and careful use of statistics to reveal important associations between dietary factors and health and disease that have been of enormous benefit to public health.

Walter Willet has been involved in some of the largest health studies conducted (and still on-going) in the United States. These include:

  • The Nurses’ Health Study, which monitored the health of 121,700 women. The study was established in 1976 by Dr Frank Speizer, and Walter Willett was involved in it since 1980.

  • The Nurses’ Health Study II, which Walter Willet established in 1989 to monitor the health of 116,000 younger women.

  • The Health Professionals Follow-up Study, which he established in 1986 to monitor the health of 52,000 male medical professionals.

Willett studied food science at Michigan State University from 1963 to 1966. He went on to study medicine at Harvard Medical School, receiving his M.D. degree in 1970.

At the Harvard School of Public Health, he obtained his Master’s degree and, in 1980, his doctorate degree in public health.

He has been Professor of Epidemiology and Nutrition at the School of Public Health since 1987. In 1992 he became a Professor of Medicine at Harvard Medical School.


Despite his illustrious career and his involvement in three mega health studies, it took Walter Willett quite a while to discover the dangers of trans fats – and his disastrous error in advising people to switch from butter to margarine.

Initially, like most mainstream medical researchers, Walter Willet conducted his studies using food data that did not take trans fats into account. In other words, his data did not differentiate between trans fats and natural fats.

Thus, like most maianstream medical researchers, he found that dietary fat consumption increased the rates of both heart disease and cancer.

Then in the early 1990s, Willett’s researchers contacted Mary Enig, a leading authority on trans fats, about the trans fats data.

Working with the refined data, Walter Willett confirmed, in the Nurses Health Study II, that nurses with higher rates of cancer were those who consumed more margarine and vegetable shortenings – not those who ate butter, eggs, cheese and meat.

This correlation between trans fat and cancer was never published, but was reported at the Baltimore Data Bank Conference in 1992.

In 1993 Walter Willet and his research group at Harvard reported that the Nurses’ Health Study found a 50 percent increase in heart disease associated with trans fats in food. In 1994, Willett reported that people who ate the most trans-fat-rich food were two times as likely to have a heart attack as were people who ate less of these fats.

Walter Willett and the CSPI

In the spring of 1994, Walter Willett joined forces with the Center for Science in the Public Interest (CSPI) to persuade the US Food and Drug Administration to require trans-fat labeling on food products.

Like Willett, the CSPI is also highly influential. It is, in fact, regarded as one of America’s most influential and vocal consumer-advocacy group. And like Willett, the CSPI had previously pushed for the use of hydrogenated oils that contain trans fats.

In 1984, the CSPI organised the first national campaign to pressure fast-food restaurants and food companies to stop frying with beef fat. Two years later, in 1986, CSPI added “tropical oils“ to its campaign.

Throughout the second half of the 1980s, the CSPI published a series of articles in its Nutrition Action newsletter, as well as a booklet titled Saturated Fat Attack, praising the goodness of hydrogenated oils and assuring that they did not pose any health risks.

After six years of pressure, the fast foods industry relented. In 1990, they switched to frying with hydrogenated vegetable oils.

But now, the CSPI, too, had realised its error and changed its tune. On 20 October 1993, CSPI called a press conference in Washington, DC, and lambasted the major fast-food chains for doing what it had pressured them to do – fry with hydrogenated fats!

Trans fat labelling

But even with Walter Willett and his team of Harvard researchers working together with the CSPI, the US Food and Drug Administration dragged its feet on the issue of trans fats.

Meanwhile, more evidence about the harm of trans fats began to pour in. By 2002, the evidence became overwhelming.

In 2002, the Institute of Medicine reported that the safe amount of trans fat in the diet is zero.

In July 2003, the FDA ruled that trans-fat food labelling must begin by January 2006.

But Walter Willett no longer believes that trans fat labelling was enough. In May 2004, Willet and 27 other scientists urged the FDA to remove hydrogenated oils from the GRAS or “generally recognized as safe” list of food additives.

Removing trans fats from the GRAS list would have similar effects as a ban on trans fats.

Controversy and criticisms

Walter Willett’s campaign against trans fats has made him controversial and unpopular – among those who still do not acknowledge the extreme harm of trans fats as well as, not surprisingly, the food industry.

In an article about Walter Willett on 12 July 2004, US News and World Report quoted Margo Wootan, Director of Nutrition Policy at the Center for Science in the Public Interest saying:

“He upsets a lot of people. He thinks about the implications of his research and advocates changes. The best example: his fight over trans fats in prepared foods.”

The same article noted: “These efforts did not endear Willett to the food industry. Indeed, some companies refused to support conferences if Willett was invited to speak.”

In researching for this article, this writer found quite a number of articles on the Internet that were highly critical of Walter Willett. Most of these articles were emotionally charged, but they had little or no scientific basis.

An alternative food pyramid

One of the most controversial things Walter Willett did, in his 2001 best-seller, Eat, Drink and Be Healthy, was to rebuild the US Department of Agriculture’s Food Pyramid and introduce his own version.

A major feature of the new Food Pyramid is that it differentiates between good and bad fats and places “plant oils” near the base, along with whole grains.

“This seems to go against conventional wisdom, it’s exactly in line with the evidence and with common eating habits,” Willett explains. “The average American gets one third or more of his or her daily calories from fats, so placing them near the foundation of the pyramid makes sense. Note, though, that it specifically mentions plant oils, not all types of fat.

“Good sources of healthy unsaturated fats include olive, canola, soy, corn, sunflower, peanut, and other vegetable oils, as well as fatty fish such as salmon. These healthy fats not only improve cholesterol levels (when eaten in place of highly processed carbohydrates) but can also protect the heart from sudden and potentially deadly rhythm problems.

Click here to read more about Walter Willett’s Food Pyramid.

Other research findings

As mentioned earlier, Walter Willett is extremely productive as a researcher. His team at Harvard publishes an average of 50 scientific papers a year, or about one a week.

Some of Walter Willett’s more significant finds on diet and disease include:

  • Positive association between alcohol consumption and breast cancer

  • No relation between fat intake and breast cancer (contrary to popular belief)

  • Positive association between animal fat and red meat consumption and risk of colon cancer

  • Strong inverse associations between vitamin E consumption and risk of coronary heart disease

  • Positive association between partially hydrogenated vegetable fats and coronary heart disease incidence

  • Inverse association between intake of calcium and kidney stones.

Glycemic Index

Walter Willett is also a strong proponent of the Glycemic Index (GI), which ranks foods according to how they affect our blood glucose levels. The Glycemic Index or GI measures the extent to which blood glucose increases during the few hours after eating.

Just as the research on trans fats differentiates between healthy and unhealthy fats, The Glycemic Index examines different types of carbohydrates rather than treat them as equal.

Foods with a high Glycemic Index – that is, foods that make blood sugar levels rise quickly – have been strongly linked not only with diabetes, but also with heart disease and other health conditions.

Most people assume that refined white sugar is the only “harmful” carbohydrate, but Walter Willett’s has thrown up some surprises.

For example, he found that certain complex carbohydrates like potato – which was previously thought to be healthy – actually cause more swings in the blood sugar level.

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May Ling
Macrobiotics & natural health practitioner of Chinese decent. May Ling provides a Yin-Yang perspective to holistic health and natural healing. Contact:

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