Dietary guidelines: where’s the evidence?

Dietary guidelines are at the core of dietetic training and practice in Australia.

Ask a dietitian a question about your diet and you’ll likely receive an answer based on the guidelines.

Take for example answers from four dietitians when asked if cheese is bad for us. Thankfully all said “no”, but every answer had disclaimers that invoked the Dietary guidelines, either in terms of allowable quantities (2-4 serves dairy per day/a matchbox size for one serve), or fat content (“This is because fat is an energy-dense nutrient and lots of us are overweight, and because a lot of the fat in cheese is the ‘bad’ saturated fat.”) ref

These comments are made by dietitians involved in training the next generation of dietitians and represent one of the many ways The Dietary Guidelines have influenced “beliefs” about nutrition, in this case, of “experts” in the field.

But should the Dietary Guidelines be afforded such a position of influence? Is the evidence base for them as strong as what many dietitians, and others, believe?

Here’s an overview of how dietary guidelines in Australia came into being, which hopefully will add some clarity to the question of whether or not they have a solid “evidence base”.

               Evolution of Australian Dietary Guidelines: 1960-2015

1960s

Not official nor government endorsed but I remember these gems from the 1960s:

1. drink milk because it is good for your teeth
2. don’t eat too many lollies because they’re bad for your teeth
3. eat your crusts so your hair will grow curly
4. Peter’s ice cream is the health food of the nation

Professor Richard Feinman once commented that in view of what we have now, these don’t look so bad.

Until the late 1950s, before Government dietary guidelines were introduced, advice on food was pretty general. Emphasis was on liberal intakes of the ‘protective’ foods such as milk, eggs, fruits and vegetables www.ecodietitians.com.au

The next decade saw the beginning of the downhill slide.

1970s

This is the time when I thought it would be a good idea to become a dietitian. I began a science degree in 1976 and completed my Postgraduate Diploma in Dietetics in 1979.

At around this time the first dietary guidelines made an appearance in Australia.

“Stop and Think Before You Eat and Drink”  was the name of a pamphlet issued in the 70’s by The Australian Dietitians Association, now known as the DAA. This little pamphlet encapsulated what could be assumed to be the organisation’s “beliefs” about healthy eating. These guidelines cannot be considered as evidence-based as there are neither references nor any documentation to support the scientific legitimacy of statements such as “limit the fat in your diet”, “reduce salt intake” and “increase your intake of ….. bread and cereals.” Also unexplained is the change from “exercise moderation in the amount of carbohydrates eaten” to “increase your intake”.

At the end of a 1978 seminar organised by the DAA, the organisation resolved to set up a committee to develop a national nutrition policy. Few responses were received to serve on the committee and the DAA members and Professor Truswell decided to go it alone and as he said“…. draft ourselves a set of dietary guidelines for Australians” ref

Within a mere eight months, this small group of people had not only written “Dietary goals for Australia” but had had them accepted and ready for presentation by the Commonwealth Department of Health.

Quoting from Truswell, two things stood out to me from his account of this time.

1. “There was no background review of the scientific literature at the time”

You’re kidding, right?

No review of the scientific literature for a professional body such as the DAA for their 1970 pamphlet isn’t great, but for the DAA to support having dietary guidelines signed off for an entire population without demonstrable evidence…how can we have ignored this action for so long?

It does however explain how the whole exercise was done so quickly; reviewing the science is time-consuming.

2. “The setting was conducive to a positive reaction.”

I get the sense Truswell may have thought getting dietary guidelines accepted by government so easily without opposition was a positive thing. This “positive reaction” may have been more a reflection of the audience, which consisted of food industry reps, consumer organisations, dietitians and bureaucrats, than an indication of the strength or soundness of the guidelines.

There was one dissenting voice to passing these dietary goals. The Nutrition Society of Australia opposed the guidelines because: “Some of its members considered dietary guidelines are politics, not science.”

Politics vs science was exactly the situation that was playing out in the U.S., where a congressional forum in 1977 to discuss the adoption of dietary goals, opposition was immense. Many researchers and scientists claimed that it was indisputable that no adequate trials had been undertaken to assess the effects, either positive or negative, of the diet changes being suggested.

This was eloquently stated by Prof E.H Ahrens, a lipid researcher from Rockefeller University, who addressed the hearing. On the proposal for Americans to reduce their fat intake, Professor Ahrens stated that this advice “…… on the strength of such marginal evidence was equivalent to conducting a nutritional experiment with the American public as subjects”.

However, politics and not science won the day. See ref for an excellent review of how this happened.

In answer to his own question as to why the Australian guidelines were accepted so well here, and weren’t met with “…… the spate of criticisms of the US dietary goals …. … or opposition like the British criticisms…..”, Truswell ref suggested the following:

1. “The scientific nutrition establishment was small and new.”
2. “Introduction of the Australian goals was well staged and tactfully presented.”
3. “Australians are more receptive to new food ideas than people in the longer established countries.”
4. “Dietary guidelines answered a deep need for the emerging profession of community nutritionists/dietitians”

So ……. not because the science had been settled?

1980s

In 1980 I started work at Queen Victoria Hospital, a large teaching hospital in Melbourne. Like many dietitians then and now, I went out into the world prepared to spread the message I had been taught: a low-fat diet with plenty of carbs as bread, cereals and fruits, is the way to good health. My apologies to every patient I counselled and the students I mentored.

It took me many years to see through this brainwashing. It wasn’t until the personal experience of having a child with a weight problem that I was forced to “think differently”. I fear that if this hadn’t been the case, I might have remained ignorant to the potential harm in recommending lower fat, higher carb diets to people who are carbohydrate intolerant . This turned out to be the majority of my clients.

The DAA pamphlet appeared in a second edition in this period. The message was the same and absence of evidence was maintained.

1990s

The 1992 edition of Dietary Guidelines for Australia link was produced by a committee of five nutritionists, one food industry representative, a psychologist and two bureaucrats. It was the first to include references, seemingly in an attempt to retrofit the 20 years of “what to eat to be healthy” recommendations.

In many sections of the 1992 Dietary Guidelines, references were far from comprehensive and appeared to be cherry picked to support each guideline. Or were mistakenly quoted as supportive when that wasn’t the case. Take for example Guideline 3: “Eat a diet low in fat and, in particular, low in saturated fat”

The basis of the demonisation of saturated fat is the belief that it raises the blood cholesterol level, and that a high cholesterol level causes atherosclerosis and cardiovascular disease. This is referred to as the diet/heart hypothesis, and has remained a theory lacking confirmation for over 50 years.

Even so, the unnamed author (or authors) of Guideline 3 attempted to back up the claim that “Saturated fatty acids elevate plasma total and LDL-cholesterol.” by citing one reference as proof.

The problem is that the referenced article is actually the OPPOSITE of supportive. Rather than it lending support to the idea that saturated fat increases cholesterol, it is CRITICAL of the methods used to incriminate saturated fat as cholesterol raising!

How could that happen? Did the author(s) not read the article or not understand it? Whichever the case, since 1992 the recommendation for Aussies to reduce saturated fat intake has been embedded in our guidelines, based on disputable evidence.

2000s

Is it possible to go from bad to worse?

The 2003 review of the guidelines suggests yes.

This decade was the golden era for industries that had anything to do with cereals and grains. It is the time when the recommendation of the Australian Dietary Guidelines was to eat “plenty of cereals (including breads, rice, pasta and 
noodles)”

And by eat “plenty”, they really did mean PLENTY. The recommendation was for women aged 19-60 to have the equivalent of 8 to 18 slices of bread and 10 to 24 for men.

Per day, no less.

How was this decision to recommend eating up to a loaf of bread per day reached? Who was responsible?

In the absence of finding anything directly answering this question, I looked at information ref about the person who wrote the chapter on breads and cereals, Peter Williams.

Peter Williams was a University of Wollongong Associate Professor of Nutrition and Dietetics 2006-2011. His publications include a paper called Report on the health benefits of whole grains and legumes for Go Grains Health and Nutrition Ltd, a paper on The benefits of breakfast cereal consumption: a systematic review of the evidence base. Adv Nutr 5:636S‐683S and a book chapter, Williams P (2003). Eat plenty of cereals (including breads, rice, pasta and noodles) preferably wholegrain. In: Food for Health: Dietary Guidelines for Australian Adults. pp31‐49. NHMRC: Canberra.

Prof Williams has received awards from the DAA for his contributions to the profession and in 2010 received Honorary Life Membership.

Professional activities of Williams include :

2002-2003 President, Dietitians Association of Australia

2000- 2003 Member, NH&MRC Dietary Guidelines Review Working Party

2000-2002 Member, the Go Grains Advisory Committee


I must admit to feeling surprised and a little uneasy when I noticed the overlap of time-frames for some of the professional activities noted above.

According to the blurb from the 2003 guideline review, preliminary work started in 2000 and revisions were finalised in 2002.

From 2000 to 2002 Prof Williams was involved with Go Grains, an advocacy body for the Australian grain industry, at the same time as he was writing the chapter for the guidelines titled “EAT PLENTY OF CEREALS (including breads, rice, pasta and noodles)”, which translated into the National advice for adults to eat the equivalent of 8-24 slices of bread per day.

2013 – now

With the foundations of our Dietary Guidelines being shaky, and, uncontested, it was no surprise to me that the 2013 review produced “more of the same”. What was disturbing though, was the number of reviewers, senior advisors, working groups, and consultation rounds, and no one was able to pipe up with even one “hang on a minute….”

There were certainly some missed opportunities for this in the latest review. Take for example the evidence statements in the 2013 guidelines for ‘limit intake of foods high in saturated fat’. Instead of this statement being graded on the strength of evidence, or even having a reference, it was simply described as ‘established’.ref

Table 3.1: Evidence statements for ‘limit intake of foods high in saturated fat’
Established evidence
Saturated fat is the strongest dietary determinant of plasma LDL concentration.

How did the brains behind this go from one reference which they thought supported the guilt of saturated fat, but which didn’t, to deciding a few years later that the matter was done and dusted, no references required?

It should be noted that the antipathy towards saturated fat reflected in the Australian guidelines is not shared by international experts such as Arne Astrup, Head of Department of Nutrition, University of Copenhagen.

In relation to a recent review of the U.S. guidelines he writes:

“The [Dietary Guidelines] committee seems to be completely dissociated from the top level scientific community, and unaware of the most updated evidence. There are now several new meta-analysis of both observational studies and also of randomized controlled trials clearly showing that there is no benefit of reducing saturated fat in the diet. All analyses and research can be criticized, but these meta-analyses have been published in leading scientific journals typically after critical reviews by 3-5 independent scientists (including a statistician), and by expert editors, so they cannot and should not be dismissed so easily….Equally important is that the scientific studies that were the basis for the ‘cut down on saturated fat recommendations have been re-evaluated, and it is quite clear that today we would have concluded that there is no robust evidence to substantiate the advice.”

And James DiNicolantonoi (Saint Luke’s Mid America Heart Institute) wrote:

“Problem three is that there was never any evidence to demonize saturated fat per se back in 1977 in the original Dietary Goals…”

—Quoted in Cardiobrief

Where to next?

I subscribe to the concept “one can criticise without having to offer solutions”, however, I feel it fair I do as a nutritionist, and on behalf of the health of Australians.

My preference is to see the scientific, social, and political communities make an admission the guidelines have been a disaster and to scrap them.

In the event that doesn’t happen and we have a repeat waste of taxpayer’s money for another review in a decade or so, at the very least my hopes are:

1. The DAA does not win the tender, and has limited involvement in the review.
2. Any person with ties to the food industry is excluded from participating.
3. A person who has reviewed a chapter/guideline previously is excluded from future reviews. An exception may be made for those of strong character who are able to admit to stuffing things up in the past and genuinely want to do better.
4. And most importantly, my wish is for the possibility of harm to be seriously considered for the first time. Not only have these guidelines not met their objective of improving health, there is a good case that they have likely caused harm to hundreds of thousands of people.

Rates of obesity and type 2 diabetes have risen dramatically. Children as young as 10 yrs are being diagnosed with type 2 diabetes. It has to be considered whether the advice to “eat less fat/plenty of carbohydrates” is implicated.

It may be that because the intention behind the guidelines was good ie to improve health, that harm has never been considered. After 40 years and deteriorating health, it’s about time it was.

Coming soon

Undoing the brainwashing: my road to recovery.