Author Archives: Jenny

Why believe us?

Why take our nutrition advice when others in the field are confidently providing contrary advice? We are troubled by this issue. It’s confusing for the public, and it’s driving the world towards a health and environmental train wreck. Meanwhile, fewer people looking to improve their health through nutrition are finding their way to WFPB.

Whole plant food diets and other vegan diets are losing the diet wars to the well-resourced meat, dairy, olive oil and processed food industries. They have successfully made low-carbohydrate diets mainstream, elevated protein above all other nutrients and discouraged vegan diets. Even within the whole foods, plant-based community, some opinion leaders are now recommending protein supplements and olive oil.

Academic qualifications and experience should be a useful guide to whom to trust, but we need to be on the lookout for conflicts of interest, such as food industry links or product sales. Healthcare leaders can be highly credentialed in their own field but have little understanding of nutrition. There are several high-profile medical doctors in Australia advocating low-carbohydrate, meat- and dairy-heavy diets. Their rationale is superficial and at odds with decades of nutrition science. While we cannot match the celebrity status of other influencers, we are confident that our qualifications in medicine, nutrition, lifestyle medicine, and health coaching lend credibility to our view of what constitutes a healthy diet. Our experience – ten years of hosting immersion retreats, webinars and seminars, health coaching, and many more years of medical consultations – has shown us what works and what doesn’t work when WFPB is put into practice. We have been in this field for long enough to understand the controversies, nuances, and uncertainties of nutrition, and we acknowledge our confirmation bias. Our approach is evidence-based, but we are not shackled by the evidence. We are open to filling gaps in nutrition science where that makes sense.

We could speak for hours about why we consider an SOS-free, whole food, plant-based diet the healthiest dietary pattern. The evidence supporting this comes from a wide range of nutrition research methods: global health observations, cohort studies, dietary intervention studies, rodent studies, cell culture studies, and knowledge of how individual nutrients and phytonutrients modulate biological mechanisms. It seems that all roads in nutrition research lead towards WFPB. There is ample evidence that animal products, in any appreciable amount, negatively impact health. Meat, dairy, and eggs are typically high in saturated fat, contain excess protein, environmental pollutants, and carcinogens, and are not necessary parts of the human diet. In recent years, nutrition science has given us more details of how ultra-processed foods damage human health. Whole plant foods provide the right balance of protein, carbohydrates, essential fats, nutrients and phytonutrients, in a fibre-rich package that supports a healthy gut microbiome. Notably, WFPB is not just about treating disease. Eating this way supports physical performance, cognitive vitality and mental health, enabling us to truly thrive.  What is most frustrating is that much of this, at least a broad outline, has been known for decades, but has not become widely accepted or acted upon. This is one of the themes in the How Not to Die Documentary.

Butter is not back. Frequent reversals in the scientific consensus of what’s healthy are a product of food industry spin and media sensationalism. Foods high in saturated fat still cause heart disease. Plant-dominant diets are the healthiest eating patterns. Nutrition science has advanced and become more nuanced, but the big picture remains the same.

Beyond health, our food systems must become mostly plant-based to sustainably provide healthy food for 10 billion people. The EAT Lancet Commission provided a science-based blueprint for a ‘Great Food Transformation’ to achieve this. Meat-centred diets are unsustainable and unethical. The treatment of animals and workers by industrial animal agriculture is unconscionable.

In his submission to a Senate committee inquiry into climate misinformation, Academic Dr Jeremy Walker was quoted as saying, “Climate policy has not failed, it has been defeated.” Nutrition policy is in a similar place. Nutrition science has already given us a roadmap for transforming human health. The destination is not precise, but the broad direction is clear.

We hope you’ll trust us to do our best to cut through the nutrition misinformation and confusion, and give you simple guidelines and strategies for your health and well-being journey.

See our livestream on this topic: Why believe us? Apologies for the blurred video. Our new ‘latest technology’ mesh modems interfered with video quality when streaming.

Olive oil and heart health

Does the CORDIOPREV study really show that extra-virgin olive oil is heart-healthy?

By Dr Malcolm Mackay

CORDIOPREV is often presented as evidence that adding extra virgin olive oil to our diet is heart-healthy. More broadly, it’s presented as evidence that a high-fat Mediterranean diet is superior to a low-fat diet rich in complex carbohydrates for treating and preventing cardiovascular disease. Some plant-based advocates now regard EVOO as heart-healthy based on CORDIOPREV and other studies. We investigated the study findings and found that the diet interventions did not match the headlines. The study diets, as followed, were not the same as the diets recommended and reported in the abstracts. The main CORDIOPREV article (Delgado-Lista et al. 2022) did not provide the diet data for this study beyond calling it ‘Mediterranean and rich in EVOO.’  An earlier study, PREDIMED (also conducted in Spain), was even less transparent with diet data, only publishing it as supplementary data. Spain is the world’s leading olive oil producer and exporter.

The CORDIOPREV study compared a ‘Mediterranean’ diet with a ‘low-fat’ diet for secondary prevention of cardiovascular disease (i.e. preventing further cardiovascular events in patients with established coronary heart disease). The seven-year study of approximately 1000 predominantly male subjects was conducted in Spain. The subjects received dietary counselling and weekly deliveries of extra-virgin olive oil or an equivalent amount of low-fat food items. The lead publication (Delgado-Lista et al. 2022) concluded: “In secondary prevention, the Mediterranean diet was superior to the low-fat diet in preventing major cardiovascular events.”

The 7-year diet data revealed some interesting differences (see Cano-Ibanez et al. 2022). Firstly, the ‘low-fat diet’ group only reduced their fat intake to 32% of calories, stretching the definition of low-fat beyond most definitions. The ‘low-fat diet’ also failed to reach the target of at least 55% calories from (mostly complex) carbohydrates, only reaching 45.5%. Saturated fat intake was similar in the two groups, 7.9% for Med. and 7.1% for low-fat. Protein intake, predominantly animal protein, was 10% higher in the low-fat group, which may have contributed to their higher incidence of cardiovascular events.

The as followed diet data showed that the Mediterranean diet group did not just add olive oil but also increased their intake of whole plant foods. Overall, the dietary changes made by the two study groups were underwhelming. However, the Mediterranean diet group recorded a statistically significant greater increase in vegetables, fruits, nuts and legumes, and reductions in fish and dairy products. These changes alone may account for the observed decrease in CVD events in the Mediterranean group. Cereal intake decreased in both groups, an apparent failure in a study designed to have a high-carbohydrate diet group.

We expect a comparative diet study without an agenda to put equal effort into both groups’ diet quality and adherence. The two groups’ fruit, vegetable and legume intake should not have been allowed to diverge. Given that the Mediterranean diet group was supplied with extra virgin olive oil rather than everyday plain olive oil, it may have been a fairer comparison if the low-fat, high-complex carbohydrate diet group intervention had resulted in a substantially increased whole grain intake.

An additional arm of the CORDIOPREV study investigated the thickness of carotid artery plaque. There was a statistically significant reduction in plaque thickness in the Mediterranean group but no change in the ‘low fat’ group. However, the difference, 0.74 down to 0.71, was minimal, particularly when over 80% of patients were taking statins (see Jimenez-Torres et al. 2021).

The seven-year cardiovascular outcomes in this study were poor in both diet groups despite most subjects taking statins. 17% of the Mediterranean diet group and 22% of the ‘low-fat’ group had further cardiovascular events. The individual patient might consider these odds unacceptable. The CORDIOPREV study is further evidence that heart disease still progresses on a Mediterranean diet rich in olive oil. The low-fat, whole-foods, plant-based diets prescribed by Ornish, Esselstyn, and Pritikin have documented far superior long-term cardiovascular outcomes including reversal.

See also:

  • See our No Oil! page for a full explanation of why we recommend avoiding this calorie-rich and nutrient-poor food.
  • Heart health section of our website

Resources

CORDIOPREV Research papers

Cano-Ibanez, N., Quintana-Navarro, G. M., Alcala-Diaz, J. F., Rangel-Zuniga, O. A., Camargo, A., Yubero-Serrano, E. M., . . . Lopez-Miranda, J. (2022). Long-term effect of a dietary intervention with two-healthy dietary approaches on food intake and nutrient density in coronary patients: results from the CORDIOPREV trial. European Journal of Nutrition, 61(6), 3019-3036.

Delgado-Lista, J., Alcala-Diaz, J. F., Torres-Pena, J. D., Quintana-Navarro, G. M., Fuentes, F., Garcia-Rios, A., . . . Investigators, C. (2022). Long-term secondary prevention of cardiovascular disease with a Mediterranean diet and a low-fat diet (CORDIOPREV): a randomised controlled trial. Lancet, 399(10338), 1876-1885.

Jimenez-Torres, J., Alcala-Diaz, J. F., Torres-Pena, J. D., Gutierrez-Mariscal, F. M., Leon-Acuna, A., Gomez-Luna, P., . . . Lopez-Miranda, J. (2021). Mediterranean Diet Reduces Atherosclerosis Progression in Coronary Heart Disease: An Analysis of the CORDIOPREV Randomized Controlled Trial. Stroke, 52(11), 3440-3449.

 

Olive oil industry research: cognitive function

This blog post is reproduced from a post we made on our Facebook page more than three years ago:

Hardly a week goes by without news of another study finding olive oil health benefits. This one by Tsolaki, et al. (2020)  claimed to show brain health benefits for subjects with early dementia. The evidence looked solid – a 12-month randomised controlled trial comparing the effects of Greek High Phenolic Early Harvest Extra Virgin Olive Oil to ordinary EVOO and to a Mediterranean diet. Support from the olive oil industry was acknowledged but that does not necessarily discredit the study. However, some of the language used in the paper did sound like spin, e.g. Greek EVOO has been “extensively suggested as a top nutritional supplement worldwide.”

The study used 12 scales of cognitive function but only found better results for special EVOO versus ordinary EVOO versus Med diet on two or three of these, and some of these barely hit the .05 statistical criteria for a non-random finding. Using many different measurements between groups and reporting those that reach statistical significance is called p-hacking – the more measurements, the more likely it is to find statistically significant differences by chance alone. The number of subjects in this study was small, 50 subjects divided into 3 groups, which increases the probability of any difference being due to chance alone – the authors said that the numbers were small because “the sponsor had no EVOO of the same quality the next year.”

Several problems with this study led us to question the validity of its findings, e.g. the abstract overstates what the study actually found. Also, the study did not give details of the Med diet that all groups were to consume, nor whether there was any difference in adherence between the three groups.

Even if it can be proven that eating high polyphenol EVOO has some protective effect, it needs to be appreciated that many whole plant foods have a much higher polyphenol content than the best olive oil (see our Polyphenol chart). We prefer to source our phytonutrients from a diversity of nutrient-rich whole plant foods, not a calorie-dense, nutrient-poor plant extract. We would like to see EVOO studies that compare it to phytonutrient-rich whole plant foods such as berries and leafy green vegetables.

Resources

Tsolaki, M., Lazarou, E., Kozori, M., Petridou, N., Tabakis, I., Lazarou, I., . . . Magiatis, P. (2020). A Randomized Clinical Trial of Greek High Phenolic Early Harvest Extra Virgin Olive Oil in Mild Cognitive Impairment: The MICOIL Pilot Study. Journal of Alzheimer’s Disease, 78(2), 801-817.

‘Glucose spikes’ and continuous glucose monitoring

The low carbohydrate diet movement has popularised the idea that the rise in blood glucose that follows a carbohydrate-based meal causes diabetes-like damage to our bodies. Health technology businesses have exploited public fear of these ‘glucose spikes’ to sell continuous glucose monitoring (CGM) to the non-diabetic public. This raises several issues that we wish to address.

Glucose spikes are normal physiology. Blood glucose rises after meals, and insulin levels rise in response. Glucose is stored in muscle, liver, and other tissues, and glucose and insulin fall back to their baseline levels. Damage to blood vessels and other tissues only occurs when blood glucose rises excessively and for many hours and baseline levels are elevated. Elevated glucose levels are also normal physiology during and immediately after intense exercise. (Inside Exercise podcast # 78)

Continuous glucose monitor (CGM) measurements are only accurate to within 20%.  Accuracy may be worse during times of rapid increases or decreases in blood glucose levels. A measurement error of 10-20% is acceptable for the purpose of managing insulin in type 1 diabetes, when combined with symptom awareness and finger prick glucose when needed. However, for short-term users of CGM without diabetes or prediabetes, inaccuracies in measurement will make it difficult to assess small differences in glycaemic response to different meals.

CGM-based dieting will not help you prevent diabetes. The whole foods that cause blood glucose levels to ‘spike’ are not the foods associated with the development of diabetes. It may seem paradoxical that eggs, processed meat, and red meat – foods that do not result in a glucose spike – are associated with the development of diabetes. This is because diabetes and prediabetes are caused by insulin resistance and the easiest way to induce insulin resistance in humans and animal models is with a diet high in saturated fat. Meat, eggs, and ultraprocessed food have other qualities that contribute to this effect.

The glucose response to a meal depends on what was consumed at previous meals. Eating high-fibre foods, particularly legumes, leads to a ‘next meal effect’. Subsequent carbohydrate meals result in a smaller rise in blood glucose. A meat-heavy low-carbohydrate diet has the opposite effect, causing insulin resistance and exaggerated ‘glucose spikes’ in response to subsequent carbohydrate meals. CGM zooms in on abnormal elevation of blood glucose, which is a symptom distracting from the real problem: insulin resistance.

A low fat, whole foods, plant-based diet (WFPB) combined with physical activity is highly effective for reversing insulin resistance (increasing insulin sensitivity). The very low fat content of WFPB, particularly saturated fats, reduces the fat in the muscle and liver cells that causes insulin resistance. Whole plant foods, in contrast to animal products and processed plants, have many other qualities that improve glucose regulation: dietary fibre, anti-inflammatory effects, more favourable amino acid profile, and weight loss due to lower calorie density of meals.

Continuous glucose monitors (CGM) enable people with type 1 diabetes to achieve near-normal blood glucose regulation. CGM has an emerging role in type 2 diabetes. In people without diabetes, CGM data may demonstrate the obvious: high-carbohydrate ultraprocessed foods lead to a rapid rise in blood glucose. However, CGM data may be misleading in identifying the best foods to eat for long-term blood glucose regulation and overall health. HbA1c remains the most straightforward and most widely available measure of blood glucose regulation.

Resources

 

Olive oil and mortality

A recent analysis from the Harvard health studies

By Dr Malcolm Mackay

A recently published study found that olive oil and other vegetable oils were equally effective in reducing mortality but more effective than other fats. However, the results have been widely misrepresented as evidence for health benefits that are unique to olive oil, even among health professionals who would usually discourage the consumption of energy dense, nutrient poor food products.

The study analysed total and disease specific mortality data from the Nurses’ Health Study and the Health Professionals Follow-up Study (1990-2018). The quantity of olive oil consumed by subjects in this study was quite small, averaging only 9g per day (half an Australian tablespoon) in the high olive oil intake group.
The introduction section of the paper conflates a Mediterranean diet with olive oil consumption – a common oversight in discussions of the healthfulness or otherwise of olive oil. The conflation continued in the discussion section of the paper in reference to the PREDIMED study, olive oil and breast cancer risk. A Mediterranean diet is characterised by limited quantities of meat and processed foods, high intakes of whole plant foods, and some olive oil and fish. It’s a healthier overall dietary pattern, not just an olive oil-rich diet.

The study found a statistically significant reduction in all-cause mortality and four categories of disease specific mortality in subjects who used olive oil. When we see observational data like this, we ask ourselves, “what other healthy habits might the item be associated with”? The statistical analysis adjusted the data to try and account for the observation that the olive oil using subjects had healthier diet and lifestyle behaviours. The other question we ask ourselves is, “healthier, compared to what”? The subjects in this study were on the standard American diet (SAD), mostly comprising animal products and processed foods. Almost any food would look good beside this.
The study contained an infographic of the potential mechanisms by which olive oil might improve cardiovascular and other health outcomes. The chart included phytochemicals and physiological mechanisms specific to high quality, extra virgin olive oil. We consider that the placement of this prominent infographic in the publication was misleading. The study did not demonstrate a health benefit specific to extra virgin olive oil. The dietary data collected did not specify the type of olive oil consumed. (The majority of commercial olive oil is not particularly high in polyphenols). Moreover, the study found no significant difference in all-cause or disease specific mortality between olive oil and other unsaturated vegetable oils.

The key figure in the publication was a forest chart of mortality ratios comparing olive oil to five groups of fats – margarine, butter, mayonnaise, other vegetable oils, and dairy fat. Olive oil was significantly better (less mortality) across all disease groups compared to margarine, butter, mayonnaise, and dairy fats. However, olive oil was no better than ‘other vegetable oils’ for total mortality or any category of disease specific mortality.
The authors of the study concluded that, “Our results support current dietary recommendations to increase the intake of olive oil and other unsaturated vegetable oils in place of other fats to improve overall health and longevity”. This is clearly a recommendation to replace worse fats with less bad fats. It was not a recommendation to eat more olive oil.

A whole foods, plant-based diet contains none of the ‘other fats’ for which olive oil would be a better choice. The fats naturally present in our diet are predominantly unsaturated, rich in essential fatty acids, and retain the fibre, nutrients and protective phytochemicals found only in whole plant foods. The addition of olive oil to our meals would add extra calories without any additional nutrients or fibre. The result would be either weight gain, reduced nutrient intake, or a combination of both.

This study is one of many published in recent years that claim to demonstrate the health benefits of olive oil. Most of the recent research on olive oil is funded by industry. We are aware of research dating back many decades that shows the detrimental effects of oil, including olive oil, on artery function and lipid metabolism. The recent olive oil industry funded studies have not overturned these older findings, rather they have ignored them.

See our No Oil! page for a full explanation of why we recommend avoiding this calorie rich and nutrient poor food.

Return to No Oil page

Study:

Guasch-Ferré, M., Li, Y., Willett, W. C., Sun, Q., Sampson, L., Salas-Salvadó, J., . . . Hu, F. B. (2022). Consumption of Olive Oil and Risk of Total and Cause-Specific Mortality Among U.S. Adults. Journal of the American College of Cardiology, 79(2), 101-112 (not available on open access)

Page created 28 March 2022
Page last updated 28 March 2022

Welcome to our articles section

We have decided to turn on our website’s blog feature so we can write articles commenting on various nutrition topics including recent nutrition research and our insights from clinical practice.

Previously, when we wrote in-depth posts, we only posted them to our Facebook page or occasionally included them in a newsletter. Having this blog feature turned on means there will be many more ways of sharing the content we write. One aim is to make our newsletters a bit shorter, giving people the option of clicking on links for further details rather than having a long email to scroll down. Another aim is to bring back into the spotlight some of the thoughtfully considered Facebook posts we have made over recent years. We will also add relevant posts to the resources section of various web pages on our website.

Malcolm and Jenny