Saturated fat: we still don’t get it

Although the headlines have got it wrong the science relating to saturated fat and heart disease has evolved considerably. But Australia’s public health nutrition policy makers are blissfully unaware and are implementing science that’s out of date.

In March yet another headline appeared in the mainstream media stating ‘No link found between saturated fat and heart disease’. The media delights in stories about diet that appear to contradict the status quo and, of course, relevant industry groups always put their public relations firms into action whenever an opportunity presents itself. Hence the misleading headlines.

Certainly there have been recent developments in how the coronary risk associated with dietary saturated fat is understood but it has to be said that the significance of these findings has still not fully registered with many nutritionists and policy makers in Australia, let alone the media. So let’s recap.

The way things were

Prior to 2009 many dietary guidelines around the world included a recommendation to eat less saturated fat on the grounds that it increased the risk for coronary heart disease. But there was always an unstated corollary to ‘eat less saturated fat’ i.e. eat more of something else. If your body weight is stable and you just eat less saturated fat you will start to lose weight, because saturated fat contains calories. To maintain weight while eating less saturated fat you have to eat more of other calorie-containing nutrients, such as carbohydrate, monounsaturated fat or polyunsaturated fat. So ‘eat less saturated fat’ really meant replace saturated fat with a healthier macronutrient.

The assumption of the old dietary guidelines was that it didn’t really matter what you replaced saturated fat with – it was thought that all replacements would lower the risk for heart disease. However, we now know that this assumption was wrong.

Image: source

The Jakobsen pooled analysis

By 2005, evidence was emerging from observational studies indicating that replacing saturated fat with carbohydrate had no effect on coronary risk. This prompted the seminal study by Jakobsen et al, a pooled analysis of 11 cohort studies with a third of a million subjects. This high quality study confirmed that replacing saturated fat with polyunsaturated fat lowered the risk for heart disease, consistent with the findings from randomised controlled trials. However, replacing saturated fat with carbohydrate was not associated with a fall in risk, but a small rise.

So the effects of saturated fat on heart disease risk were found to be modulated by the nutrient that replaced it, which had profound implications for public health nutrition. Until this point there had been two generally accepted dietary models for heart disease prevention – the Mediterranean-type diet (low in saturated fat and high in unsaturated fat) and the low fat diet (low in saturated fat and high in carbohydrate). The pooled analysis showed that the low fat diet didn’t work.

Wider debate

Extensive debate fuelled by further studies followed. Siri-Tarino and colleagues published a meta-analysis confirming that replacing dietary saturated fat with carbohydrate had a negligible effect on coronary risk. The title of a review by several key researchers highlighted the new reality: “Saturated Fatty Acids and Risk of Coronary Heart Disease: Modulation by Replacement Nutrients”. A review by Micha and Mozaffarian in 2010 summed up the evidence:

Based on consistent evidence from human studies, replacing [saturated fatty acids] with polyunsaturated fat modestly lowers coronary heart disease risk … whereas replacing [saturated fatty acids] with carbohydrate has no benefit …

One of the more interesting studies compared the risk associated with carbohydrates of differing quality with that of saturated fat and found that high glycaemic index carbohydrates actually conferred more risk for heart disease than saturated fat, which prompted an editorial by Professor Frank Hu from Harvard who asked “Are refined carbohydrates worse than saturated fat?” Among nutrition scientists a debate followed about how to define carbohydrate quality but this was lost on the mainstream media which was only interested in the sugar scare driven by non-nutritionist activists.

Nevertheless, the outcome of all of this was not that the experts had changed their minds about saturated fat; they had changed their minds about carbohydrate.

Image: source

The policy response

In the United States there was a substantial shift in nutrition policy in response to these new scientific findings. All reference to low fat diets was dropped from the Dietary Guidelines for Americans (2010) and advice about fats became to replace saturated fats with unsaturated fats. In addition, lower intake of refined carbohydrates (starch as well as sugars) was recommended. Last year a joint report from American College of Cardiology and the American Heart Association recommended the restriction of saturated fats, sweets and sugar-sweetened beverages in heart healthy diets and the inclusion of unsaturated vegetable oils.

In the United Kingdom, the Joint British Societies have just released their Consensus Recommendations on the prevention of cardiovascular disease and recommended:

• The restriction of saturated fat, being replaced by polyunsaturated fat where possible
• Reduced intakes of refined carbohydrates, such as white bread, processed cereals and sugary drinks.

Contrary to the media reports we have been reading, all of these guidelines retain a focus on lowering saturated fat intake. The change from older advice relates to the emphasis on the replacement nutrients, with unsaturated fats being encouraged and refined carbohydrates (both starch and sugars) being discouraged.

Australia makes a mess of it

While the rest of the world has been busily responding to the latest science about saturated fats, carbohydrates and heart disease Australian authorities have been asleep at the wheel. Inexplicably, the National Health and Medical Research Council chose not to conduct a systematic literature review of saturated fat and heart disease for the latest Australian Dietary Guidelines, relying instead on a review conducted 12 years ago. So the substantial shift in the emphasis in diets for the prevention of heart disease was not built into the latest guidelines or the revised Australian Guide to Healthy Eating, thereby ensuring that the next decade of nutrition education in Australia is aligned with an outdated evidence base.

Another unfortunate consequence of this policy failure is the naive use of saturated fat in the algorithm being applied to assess foods as part of the proposed star food labelling system. While saturated fat remains a useful measure of the quality of a fat-rich food, no one involved in the food labelling process seems to understand that rewarding a carbohydrate-rich food for being low in saturated fat is nonsense.

At a recent presentation on the new star food labelling system in Sydney an experienced and highly respected dietitian sitting next to me sighed “God, what a mess”.

Image: source

15 thoughts on “Saturated fat: we still don’t get it

  1. Thanks for this article Bill. As a Dietitian focused on a wholefood approach, this makes me feel much better knowing it’s not just me feeling like Australian guidelines and policy makers aren’t keeping up to speed with the research. It’s very frustrating as many alternative health practitioners are now being seen as more knowledgable than us in the realm of nutrition. We have a nation looking for advice from Google and perhaps under-qualified practitioners found via a search engine, Instagram or Facebook who are on the ball and great at sales. At the current rate, I am very curious to see where the role of an Australian Dietitian will lie in the years to come.

    • Hi Larina. Unfortunately, the process for the latest Dietary Guidelines was a mess and this is reflected in the result. On the saturated fat issue, when an early draft of the Guides effectively advised ‘eat less saturated fat; eat more carbohydrate’ the Heart Foundation, CSIRO and the Baker Heart and Diabetes Institute all wrote to the NHMRC saying that they had got it wrong and that saturated fats should be replaced by unsaturated fats, as recommended in the Dietary Guidelines for Americans (2010).
      FOUR YEARS into the Guidelines process the NHMRC finally agreed with its critics and tinkered with text of Guidelines but refused to alter the Australian Guide to Healthy Eating, which recommended that the major sources of unsaturated fats in the diet should be limited rather than increased as the science suggests.
      And now we pay the price as this outdated paradigm is promulgated through nutrition education and the star food labelling system.
      Personally, I like the idea of the star food labelling system but unless the science is correct the advice for consumers and the incentives for the food industry will be substandard.
      We really need an authoritative systematic review of saturated fats and coronary heart disease and while we are at it, it would be nice to have a review on glycaemic load and coronary heart disease and GL and type 2 diabetes. For some strange reason, the NHMRC has never conducted a systematic review on glycaemic load and chronic diseases. I wonder why? Regards, Bill

  2. I have to argue the problem is not that public health nutritionists are unaware or ‘asleep at the wheel,’ its that the food industry is being allowed to drive the ship while public health nutrition has been demoted to cabin boy.

    • Come on Nikki. You can’t blame the food industry for everything. After all, the Dietary Guidelines and the Australian Guide to Healthy Eating were developed by the National Health and Medical Research Council. No one would argue that the NHMRC’s committee was biased towards the food industry. In fact, the big criticism of the committee was that it was more interested in global warming than nutrition science.
      Yes, you could argue that the dairy industry has had an influence on the proposed star food labelling system. The early algorithm used to allocate stars rated dairy products fairly lowly, because of their saturated fat content, so the system was changed. Now I understand that three of the six categories of food considered are dairy categories, specially created to bump up the scores of dairy foods. This makes a nonsense of the whole thing. Why is saturated fat in a hamburger bad for you and saturated fat in dairy foods OK?
      The public health nutrition sector hasn’t fought this – they have embraced it. Sometimes it’s worthwhile stepping out of the trenches and reflecting. Regards, Bill

      • lol… and Bill Shrapnel consults to Goodman Fielder, Kelloggs and the Australian Oilseeds Federation. Previously, he consulted to Unilever (responsible for Miracle Margarine). And, he also previously worked for the National Heart Foundation, responsible for the tick of death program (as seen on such wonderful foods such a frozen pizza and Coco-pops!). Notice, he’s going to keep looking for evidence that saturated fat is bad for you because he doesn’t have a pay-cheque from that industry. His advice is as biased as it comes, he is a consultant to the worst of the food industry.

        • Hello Lisa. I can’t say I have ever seen a Tick on Coco-Pops. Are you sure of your facts?
          I recommended that saturated fat be replaced by unsaturated fats and I have provided ample evidence in support of this many times on this blog. Please take the time to read through and study the references.
          Virtually every nutrition authority in the world recommends the same thing so I may be onto something! Regards, Bill

  3. Thanks for the article, Bill.

    I’m still a bit confused though.

    Is it right to say that low fat diets don’t work? Or does it depend on what kind of low fat diet it is? I believe that some low fat diets, like the Ornish diet, have some pretty impressive studies that suggest that they are an effective treatment for heart disease. Have diets like these been shown to not work? I guess it depends on how the researcher defines a low fat diet, I know of some studies where the low fat group eats a diet consisting of about 30% fat! which I wouldn’t consider to be low fat.

    Also, when the study authors say ”replacing saturated fat with carbohydrate has no benefit”, it must depend on the type of carbohydrate. Doesn’t it? I find it hard to believe that someone eating less bacon and more chick peas wouldn’t be doing their heart a favour. Is it just the fibre-less refined carbohydrates that are not good replacements, or all carbohydrates? If it IS just refined carbohydrates, shouldn’t it be specified? Imagine if it were the other way around and it read ”replacing refined carbohydrates with fat showed no benefit.” I think that would be misleading since fat could be anything from biscuits to cashews. Likewise, carbohydrate could be anything from lentils to lollipops.

    • Hi Shane. You are asking all the right questions. The Jakobsen pooled analysis showed that saturated fat and carbohydrate conferred the same risk for heart disease. However, the carbohydrate referred to in this study is the sum total of all carbohydrate typically consumed by western populations. So, as you suggest, we are including everything from nutrient-poor, high GI, low fibre confectionery to nutrient-rich, low GI, high fibre legumes. The ‘quality’ of carbohydrate-rich foods differs widely and this most certainly has implications for coronary risk.
      Carbohydrate quality is still not well defined but lots of people are working on it. The measures I use to define higher quality are higher fibre (or wholegrain), lower GI and higher nutrient density. There are lots of carbohydrate-rich foods in the average diet that lack ANY of these qualities and these should be targets for reduction, or replacement with better quality carbs or unsaturated fats.
      Low fat diets are OK and most likely beneficial if they are comprised of a combination of nutrient-rich foods, wholegrains, high fibre foods and low GI foods. However, typical low fats diets are full of poor quality carbs. Similarly, high fat diets are OK if they are rich in unsaturated fats as in the classic Mediterranean diet.
      So whether a diet is low or high in fat doesn’t really matter and we shouldn’t focus on it. The quality of the fat and the quality of the carbohydrate are the key variables. Regards, Bill

      • I am confused. Do you think a low fat diet is 35% total fat? Some would say this is the same as the Mediterranean diet.

        The recommendations as I read them are to replace saturated fat with poly and mono unsaturated fats not carbohydrate. And if you include the other dietary recommendations which are to include more vegetables, fish, legumes is this not the healthy dietswe are aiming for? It does recommend limiting added fats such as oils and margarine’s but not poly and mono unsaturated fats from whole foods such as nuts , seeds, fish, avocado, olives, nut pastes

  4. Hi Bill,

    Do you have a summary or some references to combat the pro-paleo argument that more saturated fat is better? Are there any studies that have actually compared high saturated fat (equivalent of what some of these pro-paleo-butter-and-coconut-oil-in-my-coffee-6-eggs-and-bacon-for-breakfast-type are having), to replacing sat fat with carbs or unsat fat evidence/disease risk. As that is how the media’s version of these studies have been interpreted by some.

    • Hi Hellene. The onus is really on those pushing the more-saturated-fat-is-better argument to mount a decent scientific argument to support their case. What the science is actually telling us is that saturated fat and carbohydrate are now known to confer the same risk for heart disease. So, if saturated fat is increased in the diet at the expense of carbohydrate there should be no harm. But importantly, there is no benefit either, so this can’t be portrayed as a healthy option.
      In contrast, unsaturated fats are a better option than either saturated fat or carbohydrate. Most dietary authorities recommend the replacement of saturated fat with unsaturated fat. However, there is an equally valid argument for replacing carbohydrate with unsaturated fats – giving higher fat diets, but enriched with unsaturated fats rather than saturated fats.This is like the Mediterranean diet, only more so.
      The scientific trials testing this option are only now being conducted and one from CSIRO has just been published.
      This shows the benefit of a higher fat, high unsaturated fat diet for people with type 2 diabetes. No health authority is recommending high saturated fat diets though. Regards, Bill

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