The Dietary Guidelines Experiment: Part 2

 

The idea of introducing population-wide dietary goals to the small Swedish population might be seen as curious to some.

Obesity did not appear to be a public health issue of concern. In addition, heart disease rates were low compared to other countries, particularly the United States.

With the benefit of hindsight, we now know that the Swedish dietary goals agenda did change food consumption patterns and this was noted in both food consumption statistics and in the obituary of Swedish professor, Arvid Wretland, one of the plan’s key architects.

But the experiment did not stop obesity.

By the 1980’s obesity rates in Sweden were trending up. Today, around half of Sweden’s population are either overweight or obese.

And it did not stop people dying from heart disease.

Rates actually increased for the next 12-15 years, before falling, likely as a result of modern medicine.

It might have been a good idea to have stopped the diet experiment there.  It was becoming self-evident that population-wide dietary instructions were not a panacea to obesity or heart disease.

The great diet experiment moves to America

On Valentine’s Day, 1977 the ‘Dietary Goals for the United States‘ was published. Senator George McGovern spoke at the press conference and expressed his hope that the document would serve a similar function to that of the ‘Surgeon General’s Report on Smoking‘. McGovern stressed that the consumption of sugary soft drinks had more than doubled since 1960, claiming that in 1976 every man, woman and child in the United States had consumed around 45kg of sugar (substantially more than the Swede’s at 27.89kg) and 57kg of fat. “The simple fact is that our diets have changed radically within the last 50 years, with great and often very harmful effects on our health…Too much fat, too much sugar or salt, can be and are linked directly to heart disease, cancer, obesity, and stroke, among other killer diseases.

McGovern was not the only person to make a statement that day. Dr M. D. Hegsted a nutrition academic from Harvard also strongly supported the need to introduce dietary goals. Hegsted pointed to the ‘rich’ American diet that featured, to his mind, far too much saturated fat and cholesterol. Contradicting McGovern, however, he noted that “total sugar use has remained relatively constant for a number of years.” Hegsted conceded that his critics “will say we have not proven our point” but challenged the idea that ‘risks’ might be associated with the promotion of a national diet based upon:

  1. Less meat
  2. Less fat
  3. Less saturated fat
  4. Less cholesterol
  5. Less sugar
  6. Less salt
  7. More fruits and vegetables and cereal products (especially whole grain cereals)
  8. More unsaturated fat

Hegsted concluded that as far as risks were concerned, they pertained only to the continuation of the nation’s supposed fatty diet. As for the risks associated with adopting the guidelines, “none can be identified and important benefits can be expected.”

The solution to America’s health woes was straightforward (and risk free).

Follow the lead of the Scandinavians and implement a set of population-wide dietary goals. Like Sweden, these goals were based on ‘consensus’ rather than irrefutable scientific evidence – particularly around lowering ‘fat’ intake and the decision to increase carbohydrate consumption to make up for the reduction in fat. The guidelines were as follows:

  1. Increase carbohydrate consumption to account for 55-60 percent of the energy intake (increase consumption of fruits, vegetables and whole grains)
  2. Reduce overall fat consumption from approximately 40 to 30 percent energy intake (decrease consumption of foods high in fat and partially substitute polyunsaturated fat for saturated fat)
  3. Reduce saturated fat consumption to account for about 10 percent of total energy intake; and balance that with poly-unsaturated and mono-unsaturated fats, which should account for about 10 percent of energy intake each (substitute non-fat milk for whole milk)
  4. Reduce cholesterol consumption to about 300mg per day (decrease consumption of butterfat, eggs and other high cholesterol sources)
  5. Reduce sugar consumption by about 40 percent to account for about 15 percent of total energy intake (decrease consumption of sugar and foods high in sugar content)
  6. Reduce salt consumption by about 50 to 85 percent to approximately 3 grams per day (decrease consumption of salt and foods high in salt content)
  7. (Note: An additional change in food selection for consumers read ‘decrease consumption of meat and increase consumption of poultry and fish’)

Figure 1 illustrates the proposed transition from the existing consumption habits of the US population in 1977 to the new dietary goals

 

Figure 1.  1977 United States Diet compared to 1977 Dietary Goals for the United States

A Norwegian doctor weighs in

Several months later, on June 13, 1977, Dr Kaare Norum of the University of Oslo published the results of a survey in the Journal of the American Medical Association. The goal of the survey, which had been issued to 200 scientists from 23 countries, was to determine their view of the relationship between diet and health.

The ‘survey’ itself was noted to have certain limitations.

A Dr David Kritchevsky suggested that the “survey would have been more useful if the respondents had been asked to weigh, on a 1-5 scale, the relative importance of each dietary factor rather than simply indicating whether or not it was associated with heart disease.”  Bearing Kritchevsky’s criticism in mind, the results of the questionnaire found that 99.9 percent of respondents believed that there is a connection between diet and the development of heart disease. In addition, 91.9 percent believed that the current knowledge in the area was sufficient to recommend a moderate change in diet.

The respondents presented their recommendations in order of priority:

  1. Fewer total calories
  2. Less fat
  3. Less saturated fat
  4. Less cholesterol
  5. More poly-unsaturated fat
  6. Less sugar
  7. Less salt
  8. More fibre
  9. More starchy foods

The recommendations were not too different from the original Scandinavian ‘consensus’ diet guidelines, which remained in the same order.

  1. The dietary energy supply should, in many cases be reduced to prevent overweight (fewer calories)
  2. The total fat consumption, at present about 40 percent, should be decreased to between 25 and 30 percent of total calories (less fat)
  3. The use of saturated fat should be lowered, and the consumption of polyunsaturated fat should be simultaneously increased (less saturated fat; more polyunsaturated fat)
  4. The consumption of sugar and products containing sugar should be less (less sugar)
  5. The consumption of vegetables, fruits, potatoes, skimmed milk, fish, lean meat and cereal products should be increased (more fibre and starchy foods)
  6. From the medical and nutritional standpoint, the importance of taking regular exercise from an early age for all those who have mainly sedentary occupations should also be emphasised.

The use of a poorly designed questionnaire, which ultimately returned a similar result to the original Scandinavian goals and to Hegsted’s 8 points, suggests a cohort of transatlantic nutritionists determined to get their way.

December 1977 – the US dietary goals look shaky

The introduction of dietary goals did not go quite as smoothly in the United States as it had in Sweden.

In fact, the introduction of the goals caused a kerfuffle.  This was due in no small part to the emergence of an ‘extreme diversity of scientific opinion’, the details of which were reflected in a number of amendments detailed in a second report ‘Dietary Goals for the United States, Second Edition’.

The Foreword of this document, prepared by Senators Percy, Schweiker and Zorinksy from the Select Committee on Nutrition and Human Needs, revealed reservations about information contained in the original report.

“I have become increasingly aware of the lack of consensus among nutrition scientists and other health professionals regarding:

  1. The question of whether advocating a specific restriction of dietary cholesterol intake to the general public is warranted at this time.
  2. The question of what would be the demonstrable benefits to the individual and the general public, especially in regard to coronary heart disease, from implementing the dietary practices recommended in this report.
  3. The accuracy of some of the goals and recommendations given the inadequacy of current food intake data.

The medical profession also registered some concern:

Advice to the public on changing its dietary habits in hope of reducing the rate of new events of coronary heart disease is premature, hence unwise.” (Dr. E.H. Ahrens, Jnr., Professor of Medicine, Rockefeller University)

The evidence for assuming that benefits to be derived from the adoption of such universal dietary goals as set forth in the report is not conclusive and…potential for harmful effects…would occur through adoption of the proposed national goals.” (American Medical Association)

In addition, Senator Percy issued his own stark warning about the risks of prematurely introducing the proposed dietary change:

“I feel the American public would be in a better position to exercise freedom of dietary choice if it were stated in bold print on the Goals and Food Selection pages that the value of dietary change remains controversial and that science cannot at this time insure that an altered diet will provide improved protection from certain killer diseases such as heart disease or cancer.”

The revised US Dietary Goals were as follows:

  1. To avoid overweight, consume only as much energy (calories) as is expended; if overweight, decrease energy intake and increase energy expenditure
  2. Increase the consumption of complex carbohydrates and ‘naturally occurring’ sugars from about 28 percent of energy to about 48 percent of energy
  3. Reduce the consumption of refined and processed sugars by about 45 percent to account for about 10 percent of total energy intake
  4. Reduce overall fat consumption from approximately 40 percent to about 30 percent of energy intake
  5. Reduce saturated fat consumption to account for about 10 percent of total energy intake; and balance that with poly-unsaturated and mono-unsaturated fats, which should account for about 10 percent
  6. Reduce cholesterol consumption to about 300mg a day
  7. Limit the intake of sodium by reducing the intake of salt (sodium chloride) to about 5 gram a day

Changing the national diet to fight chronic disease

The prospect of turning the tide on heart disease, obesity and stroke must have been intoxicating to public health academics and political leaders at the time. After all, based on the Swedish experiment, they already knew that the people were likely to listen and act.

It would be only a matter of time before the war against food-related chronic diseases would be handed a decisive defeat.

Or would it?

 

Sources: (1) Lissner, L., Johansson, S-E., Qvist, J., Rossner, S., Wolk, ‘Social mapping of the obesity epidemic in Sweden’, International Journal of Obesity (2000) 24, pg. 801-805   (2)Dietary Goals for the United States’, Second Edition, Washington, 1977

 

Part 3 coming soon…