Tag Archives: Fats

What are ‘good fats’?

‘Good fats’ has become an overused almost meaningless health label.

We advocate a  whole food plant-based diet – a diet built mainly on whole grains, legumes, vegetables, and fruits. This is a low-fat diet because most of the energy these foods provide is in the form of carbohydrates and proteins with only a small contribution from fat. It’s the dietary pattern with evidence for reversal of heart disease and insulin resistance and is of low caloric density, assisting weight loss. The macronutrient ratio (typically >70% carbohydrate, 10-15% protein, 10-15% fat) is a consequence of the composition of our core foods rather than the macro ratio determining our food choices.

“But what about good fats?” is a question or objection often raised when we describe our low-fat dietary approach and the amazing health results we see when people eat this way. People love their fat-rich foods, and the dairy, olive oil and nut industries have successfully dismantled the low-fat diet paradigm during the preceding couple of decades. ‘Good fats’ have gained de facto status as a food group and even many plant-based foodies seem to regard ‘good fats’ as an essential component of every meal. In mainstream nutrition Australians are being encouraged to add hundreds of calories of olive oil to their meals every day in the name of ‘good fats’. Has anyone paused to consider what a ‘good fat’ is? It would seem not when we review the composition of many of these so-called good fats.

Criteria for a ‘good fat’

Whole food: Our first criterion for a ‘good fat’ is that the fat is in the context of a whole food. Vegetable oils and margarine are not ‘good fats’ because they have lost all the fibre and most of the nutrients of their plant of origin (see our No Oil page).

Low in saturated fat: ‘Good fats’ are good because bad fats – i.e. saturated and trans fats – are bad for our health. Any ‘less bad’ fat than these are usually labelled a ‘good fat’ by nutritionists. We can sideline trans fats because they have been largely eliminated from ultra-processed foods, leaving ruminant meats and dairy as the primary dietary source. Saturated fats are widespread in both plant and animal-derived foods. The issue is how much saturated fat does it take to lose the ‘good fats’ tick of approval? The commonly accepted upper healthy limit of saturated fat intake is 10% of total dietary calories. The American Heart Association recommends an even lower target of 5% to 6% of calories from saturated fat. Adding in more calories from foods with a greater percentage of saturated fat than this (e.g. olive oil or avocado) is never going to get us to these targets. How do some common ‘good fats’ compare to these criteria?

Saturated fat as a percentage of total calories:

 

Olive oil, avocado, and many nuts owe their ‘good fats’ label to their high monounsaturated fat content. Monounsaturated fats have a neutral effect on blood cholesterol and metabolic health. We have no requirement for monounsaturated fats other than as a source of calories (energy). Plants with a high monounsaturated content may qualify as ‘good fats’ if they meet our criteria.

Essential fat ratio: The only ‘good fats’ that are essential are two groups of polyunsaturated fats, the omega 6 and omega 3 series. Human requirements for these amounts to only a few percent of daily energy intake and clinical deficiency is extremely rare. What may be more relevant is the ratio (omega-6: omega-3) as the two groups are transformed within the body by the same enzymes, and too much of one may compromise conversion of the other into the long chain form. The modern diet has become skewed towards the omega-6 group, far from the optimal ratio of 4:1 or less. This is thought to contribute to long-term adverse health outcomes. Omega-6 fats are widespread in grains, nuts, seeds, and oils and are more often present in the diet in excess. In contrast, few foods are high in omega-3 fats. The omega-6 to omega-3 ratio of the total dietary pattern is important, rather than that of individual food items. One could eat some high omega-6 meals and counterbalance these with other meals of higher omega-3 content. However, anticipating that something else will compensate for what’s currently on our plate can be a slippery slope in nutrition. Giving the ‘good fats’ tick to foods low in omega 3’s may take people further from an optimal fat ratio. Our final criterion for the ‘good fats’ label is that the item has an omega 6 to omega 3 ratio supporting a total dietary ratio of 4:1 or less. Many foods promoted as ‘good fats’ do not meet this criterion.

Omega 6 to omega 3 ratio in foods of moderate to high fat content:

*Green leafy vegetables are low in fat therefore it takes a lot of them to have a meaningful effect on your omega-3 intake.

The aim of this article was to bring nutrition science into the ‘good fats’ meme to help you make healthier food choices, regardless of where you are on the fats-starches continuum of whole foods, plant-based nutrition. Some individuals and groups may benefit from eating more ‘good fats’ to maintain an adequate calorie (energy) intake. Our personal low-fat, WFPB diet includes ground flaxseed, a few walnuts, a little peanut paste, and tahini as condiments.

Our ‘good fats’ tips:

  1. Source ‘good fats’ from whole foods or minimally processed whole foods.
  2. Limit consumption of ‘good fats’ with a higher saturated fat content, particularly if you have heart disease or type 2 diabetes.
  3. Choose ‘good fats’ with a lower omega 6:3 ratio.
  4. Balance higher intakes of omega 6 predominant ‘good fats’ with increased omega 3 foods.
  5. Be mindful that high-fat foods are calorie-dense and good for weight gain.

Related pages:

Resources

 

Page created 30th December 2023
Last updated 5th January 2024

Why do we recommend a low-fat diet?

In recent years, the long standing recommendation to eat a low fat diet has been questioned. There has been a sustained attack on low fat diets that goes beyond the rational consideration of higher fat alternatives. Language such as “Low fat diets are dead”, “old nutrition” and “the nail in the coffin for low fat diets” are not terms one would expect to hear from nutrition scientists. Neither would one expect to find that research cited to discredit low fat diets did not actually have any subjects eating low fat diets – the PREDIMED Study for example had a “low fat” group who averaged a 37% fat diet. It is interesting to consider which industry groups might have the most to lose were low fat diets to become reality rather than rhetoric – the pharmaceutical industry would be in there along with the meat, egg and dairy industries. These industry groups have become big sponsors of nutrition research.

The ongoing health debate over carbs vs fats is a gross oversimplification of the types of foods that contain these nutrients and positions animal protein beyond reproach. It sometimes seems to us that the fats vs carbs debate is a proxy used to argue for increased consumption of fat-rich animal products over starchy plant-based foods – an idea that would be quickly dismissed if it were not disguised by talking about nutrients rather than foods. It is ironic to hear of people on plant-based diets embracing the calls of the meat-based Atkins-Paleo advocates to eat a more fat-rich, reduced carbohydrate diet.

We are confident to continue to recommend a low fat diet as optimal, not because we are clinging to an outdated paradigm, but because the nutrition research of recent years has not provided good evidence to overturn the cumulative research findings of the last 50 years supporting the health benefits of a low fat plant-based diet. The following are our reasons for recommending a diet based predominantly on the low fat whole plant foods. The list includes points that are well supported by evidence from population studies, clinical trials and intervention studies, as well as other factors that we consider relevant:

  • All lean healthy populations that were free of heart disease and other Western diseases have had diets based on low-fat starchy staple foods such as rice, wheat, beans, corn and potatoes.
  • While modest quantities of olive oil were used by some Mediterranean cultures, their overall diet was largely based on grains and legumes, leaving us with no observations of the long term health effects of a diet based on high-fat plant foods.
  • The randomised controlled trials and intervention programs that have had the most remarkable results in treating heart disease (Pritikin, Ornish, Esselstyn), diabetes (Barnard) and other Western diseases have all used low-fat, high-carbohydrate, plant-based diets.
  • The plant-based nutrition experts with the most knowledge and clinical experience, with few exceptions, advocate a diet based on whole grains, legumes, vegetables and fruits – i.e. the low-fat plant foods.
  • A low-fat, whole foods, plant-based diet reduces body fat without food rationing. Starchy plant foods generally have a lower calorie density than high-fat plants and the metabolic process of converting excess carbohydrate to body fat is inefficient.
  • High intakes of dietary fat, particularly saturated fat, leads to fat accumulation in the muscle cells and liver cells, resulting in insulin resistance and type 2 diabetes.
  • The health benefits of adding nuts to a Western diet (i.e. one that is extremely low in whole plant foods) may not extrapolate to added health benefits for those already consuming mostly whole plant foods. The quantity of nuts observed to reduce health risks was only a small fraction of the diet, typically 30g per day.
  • Humans are highly adapted to starch-based diets. We have multiple copies of the starch digesting enzyme, amylase, and we even secrete it in our saliva so that starch digestion begins as we chew. Our over-sized brain uses 20% or more of our resting energy and runs exclusively on carbohydrates except during periods of prolonged fasting. Our muscles can only perform at their peak when they have been adequately ‘charged’ with carbohydrates.
  • High carbohydrate plant foods provide the resistant starch and dietary fibre that nourish healthy gut microbes. While much remains to be learnt about our gut microbiome, we know that it only takes a few days of high fibre, starchy foods to build a healthy pattern of microbes. Low carb dieters forget that most dietary fibre is composed of carbohydrates.
  • ‘Good fats’ is more an endorsement of high fat foods than a meaningful definition. Foods with moderately high saturated fat content, low omega 3 fat ratios and minimal nutrients and fibre have all been called good fats. Perhaps the term just means that there are worse fats that could have been chosen. ‘Good fats’ are said to be the reason why the Mediterranean diet is not as bad as the standard Western diet, although we suspect it’s because it’s more plant-based.
  • Most high-fat plant foods (nuts, avocados, olives etc.) have an omega 6:3 fatty acid ratio greatly in excess of the suggested optimal ratio of 4:1 or less. Flaxseed, chia seed and hemp seeds are exceptionally high in omega 3’s and may be beneficial in small quantities (amounts compatible with a low fat diet). High intakes of omega 6’s provide more precursors for the production of inflammatory omega 6 mediators and inhibits the production of anti-inflammatory omega 3 mediators.
  • Many of the plant foods that are considered to be ‘good fats’ are actually moderately high in saturated fats – 15% of calories in avocados and olive oil for example. Saturated fats are damaging to the intestinal lining, raise cholesterol levels, have adverse effects on blood and endothelial cells and increase insulin resistance. To what degree other components of whole plant foods counter these effects is uncertain.
  • Women’s health can be adversely affected by high fat intakes due to increased production and recycling of oestrogens. The excess oestrogen levels cause heavy bleeding, uterine fibroids and breast disease. High omega 6 fat intake, particularly arachidonic acid from animal products, promotes inflammation and menstrual pain.
  • Consumption of high fat foods results in lipaemic blood – centrifuge this blood and the serum layer appears milky. Lipaemic blood impairs the capacity of arteries to dilate and causes red cells to clump and stick as they flow through capillaries. High intakes of high fat plant foods may have the same effect – see this video by ultra-distance runner Randy Kreill whose diet was heavy in high fat plant foods.
  • A single high-fat meal increases blood clotting through activation of Factor VII
  • The final point is that a diet based largely on high fat plant foods is unprecedented from a population perspective and has not been adequately assessed by clinical trials. It’s an ‘experimental’ diet in comparison to the ‘evidence-based’ starch-based diet.

How much fat is OK?

After explaining why we advocate a low fat diet, people often ask us what macronutrient ratio they should aim for. We prefer to turn this reasoning around the other way, such that it’s the food group recommendations that come first, and the macronutrient ratio becomes just one of many metrics, including fibre content and calorie density, that describe this dietary pattern, recognising that whole plant foods have a composition and complexity that is not adequately described by a handful of measurements or a full nutrient analysis. We recommend a diet based on whole grains, legumes, starchy and non-starchy vegetables and fruit. Nuts and seeds are optional and are limited to a small proportion of the total diet – with the type and quantity depending on individual energy balance and health status. If you follow this pattern, then your ‘macros’ will be in the vicinity of 70-80% carbohydrate, 10-15% protein and 8-15% fat.

Related pages:

Resources

Page created 26th June 2016
Last updated 4th April 2020

What’s wrong with saturated fat?

There has been so much media coverage lately about saturated fat, with newspaper and magazine articles, and even peer reviewed journal articles claiming that saturated fat isn’t that bad after all. This news is well received by people who love to hear good news about their bad habits. It allows people to avoid the difficulty of change and to keep eating the foods that are making them sick.

Lurking in the background behind the saturated fat issue are powerful industries (in particular the dairy industry) whose products are relatively high in saturated fats. Most guides to healthy eating include the advice to eat less saturated fat, but they shy away from naming those foods we should eat less of for fear of offending the meat and dairy industries. So we end up with recommendations that mix food advice, e.g. eat more fruit and vegetables with nutrient advice e.g. eat less saturated fat. Why not just say “eat less cheese”?

The saturated fat/high cholesterol/atherosclerosis/heart disease link is well established. Nothing has changed to refute decades of research which link high fat animal products with heart disease, diabetes, cancer and other diseases. The only real challenge to the ‘saturated fat is bad’ paradigm is whether some of the adverse effects of foods high in saturated fat might be due to other features of these foods such as animal protein, carnitine, choline or haeme iron. For practical purposes it doesn’t really matter whether it’s the saturated fat or something else – it’s still meat and dairy foods that are contributing to chronic disease.

Many of the stories woven to refute the health hazards of saturated fat are based on several key scientific publications:

  1. Chowdhury, R., Warnakula, S., Kunutsor, S., Crowe, F., Ward, H. A., Johnson, L., . . . Di Angelantonio, E. (2014). Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk: A Systematic Review and Meta-analysis. Annals of Internal Medicine, 160(6), 398-406.
  2. Malhotra, A. (2013). Saturated fat is not the major issue. BMJ, 347, f6340. doi: 10.1136/bmj.f6340
  3. Siri-Tarino, P. W., Sun, Q., Hu, F. B., & Krauss, R. M. (2010). Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. American Journal of Clinical Nutrition, 91(3), 535-546. doi: 10.3945/ajcn.2009.27725 (NB This research was funded by the dairy industry)

It all sounds quite plausible until you actually look at the fine detail of the evidence given, which takes considerable time and skill… few health professionals do this, so what hope has the general public got? We are indebted to people like Plant Positive, Dr John McDougall, Dr Michael Greger, T Colin Campbell and others who invest the time and effort to cut through the smoke and mirrors. Below is an extensive list of resources that will help you understand what’s behind the sensational headlines.

Resources

These videos from Dr Michael Greger explain how industry works to confuse the public on the saturated fat issue. The second video presents powerful evidence that saturated fat does indeed raise blood cholesterol and the risk of heart disease:

An extensive analysis of this topic is provided by Plant Positive. His whole website (and YouTube channel) is designed “to correct specific falsehoods and flawed arguments that pervade the popular and academic discussion of nutrition”:

Addressing the Siri-Tarino and Chowdhury Saturated fat articles:

Cholesterol **February 2015 update**

In Feburary 2015 it was reported that the new US dietary guidelines will withdraw their recommendation to limit dietary cholesterol. Below are some responses from plant-based practitioners:

Saturated fat and cardiovascular disease **June 2017 update**

In June 2017 the American Heart Association published a ‘Presidential Advisory’ written by a team of highly experienced researchers who conducted a thorough review of the scientific literature into the effects of dietary saturated fat:

David Katz, MD wrote several articles trying to counter the pushback from low carb/high fat advocates in the days and weeks following publication of the AHA paper:

Ancel Keys’ research:

This white paper was commissioned by the True Health Initiative to explore the historical record and address the popular contentions with primary source material and related work, and in consultation with investigators directly involved. Popular criticisms directed at the study, and the lead investigator, Ancel Keys, turn out to be untrue when the primary source material is examined:

Books:

  • Campbell, T. C., & Jacobson, H. (2014). The low-carb fraud. Dallas, Texas: BenBella Books, Inc.

Related pages:

Page created 4 July 2014
Last updated 8 July 2017