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 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

Two recent (January 2015) 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”:

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:

Other responses:

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

Humans are Herbivores

You may argue that humans are omnivores but it is clear that our anatomy and physiology are those of a herbivore. The following cartoon makes this point:

There is a popular fallacy that humans as a species are well adapted to eating meat and wild plants but little carbohydrate. Also that eating more grains and root vegetables results in chronic diseases such as diabetes. It is difficult to reconcile this theory with the fact that there is least diabetes in the populations who consume the most carbohydrate, and most diabetes in the developed countries where meat, dairy and oil has displaced much of the basic starchy (carbohydrate) food from the diet.

The low carbohydrate enthusiasts claim that we evolved on a meat rich diet. A frequently quoted publication on the Paleolithic diet considered the diets of modern day hunter-gatherers and concluded that their diets were rich in foods of animal origin, leading to the conclusion that the natural human diet is meat based. The first major flaw in this publication was that it relied on old data, which was not collected reliably, and underestimated the amount of plant foods that these people gathered. The other flaw was that the last enclaves of hunter-gatherers were often marginalized into land that was not agriculturally productive and therefore provided limited sources of foods. It is likely that the majority of the Paleolithic humans lived in more productive lands abounding in plant sources of food. There is considerable evidence that early humans had diets that were mainly based on high carbohydrate starchy foods such as grains and root vegetables.

The development of a larger brain was not dependent on eating meat or fish. The mother provides the increased needs for omega-3 fats during the most rapid periods of growth in pregnancy and infancy. After weaning, human growth is incredibly slow and the main extra nutritional cost of a big brain is the energy it consumes, about 20% of resting metabolic rate. The brain runs almost exclusively on carbohydrate: “brain food”?

We don’t know how much meat versus plant our ancestors ate over the last couple of hundred thousand years. The advent of fire and cooking enabled our ancestors to eat things that were poorly digested or hazardous when raw, and greatly increased the range of foods we could eat, both plant and animal. Meat was not an ideal health supporting food for our ancestors, but it was energy dense and in hard times, it was better than hunger and starvation.

Evolution does not seem to have endowed us with a meat eating body or metabolism. We have hands that are suited for picking and collecting the edible parts of plants. We lack claws to attack prey and our skin is soft and vulnerable to laceration should we wrestle with another animal. Neither our hands nor our teeth are suited for tearing the flesh off a carcass. To a paleontologist, our teeth and jaw muscles are those of an herbivore, primarily designed for grinding food rather than tearing and chopping. We lack the large stomach of a carnivore and our intestine is long like an herbivore’s. Our large intestine is adapted to ferment plant foods to extract more energy. And we are vulnerable to disease when we eat more meat. Our cholesterol metabolism, like other herbivores, makes us vulnerable to artery disease when we eat more saturated fat and less fibre.

We are better adapted to eating starchy foods than the great apes who live on fruits and leaves in tropical forests. We have more copies of the gene for the starch digesting enzyme, amylase. Amylase mainly works in the small intestine, but we also have a higher concentration of amylase in our saliva. This adaption enabled us to take advantage of grains and roots of plants that store their energy as starch for the next growth season. Starch granules have been retrieved from surfaces of stone tools in Mozambique, dating back to 105,000yr ago, and from the teeth of our Neanderthal cousins in Europe.

The epidemiology overwhelmingly supports a high starch, predominantly plant based diet as being most health supportive. Cancer, heart disease and diabetes are least common in populations that have the most plant strong diets. Within developed nations, those who consume a more plant-based diet are healthier.

The most effective lifestyle intervention programs for reversing heart disease, diabetes and, most recently, prostate cancer all used a mostly plant-based, low fat diet.

Resources

Low carbohydrate diets

Low carbohydrate diets have been around for decades and were epitomised and popularised by the Atkins Diet. So much evidence condemning these diets has been published that you would expect them to be of historical interest only. But strangely the fad continues with its latest reincarnation being the Paleo Diet. Let us make one thing clear:

a low carbohydrate diet is a high fat, high protein diet

This is explained on the Energy Pie page.

Resources

Related pages