The definition of “healthy eating” in 2017 is decidedly debatable.  Many of our well-established nutritional guidelines appear to be crumbling under recent scrutiny.  Did you know that restricting salt consumption may not reduce your risk of hypertension and may actually be harmful? Or that dietary cholesterol (from food sources such as eggs) likely has no significant impact on blood cholesterol?*  The most recent nutritional guideline to be allegedly disproven is the need to avoid saturated fats. Call me cautious, but I was finding it difficult to let go of this one. I decided to dig in a bit more deeply.

The Diet-Heart Hypothesis

Saturated fats are found in meat products, dairy products and tropical oils like coconut oil and palm oil. The recommendation to reduce our saturated fat intake originated with the theory that saturated fat causes heart disease. Ancel Keys, a biologist at University of Minnesota, first proposed and promoted “the diet-heart hypothesis”. in the 1950s.

Ever since, North Americans have been told to lower their fat intake, particularly saturated fats.  The American Heart Association first officially recommended  a low-fat, low cholesterol diet in 1961, based largely on Keys’ recommendations. 

Nutrition Canada first asked those living in Canada to reduce our fat intake in the early 1970s.  Warnings against saturated fat are still official Health Canada policy.  From their website:  “Saturated fats are not good for your health.  They can increase your risk of heart disease because of how they affect your cholesterol levels.”  Next year’s iteration of Canada’s Food Guide will still recommend a lower consumption of red meat. The new guide is rumoured to lean towards a more vegan diet rather than omnivorous.

In the early 2000s, Naturopathic College taught that saturated fats are bad for us.  From my year 3 nutrition notes (yes, I still have them), “Reduce saturated fat intake to less than 10% of calories for reducing risk factors of cardiovascular disease.”

But what if all this is wrong?

The Big Fat Surprise

I recently read investigative journalist Nina Teicholz’s eye-opening book “The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet”.  Teicholz spent 9 years exhaustively poring over the research on fat and heart disease. She interviewed many nutritionists and scientists involved in this issue for the last several decades. She proposes that the diet-heart hypothesis “was likely driven less by sound science than by longstanding bias, commercial interests and the AHA (American Heart Association)’s need to reaffirm nearly 70 years of “heart healthy” advice”.

“The Big Fat Surprise” is a fascinating read.  According to Teicholz, many of the epidemiological studies that supported the diet-heart hypothesis were “deeply flawed”. Researchers like Keys ignored or delayed publishing data that didn’t support the diet-heart hypothesis.  There were researchers who disagreed with Keys and were virtually barred from certain publications, or had their grant money cancelled.  

Teicholz argues that bad science, a few strong personalities, industry bias, and some scientific bullying all led us to the wrong conclusion.  According to Teicholz, the cause of an increase in heart disease is more likely to be sugar or polyunsaturated oil (such as corn oil or soybean oil) consumption rather than saturated fats. 

And Teicholz certainly isn’t alone.  American science writer, Gary Taubes thoroughly debunks the merits of a low fat diet.  And there are a growing number of outspoken scientists and medical professionals who are also critical of a low fat diet:  Tim Noakes, South African author and science activist, Dr. Gary Fettke, an orthopaedic surgeon from Tasmania, Dr. Jason Fung, a Low-Carb High Fat (LCHF) Diet advocate in Canada, and Dr. Andreas Eenfeldt, Swedish medical doctor and author. Both Noakes and Fettke are encountering legal battles with their country’s dietetic associations because they promote high fat diets.   

Saturated Fats and the PURE Study

There is also new compelling research underway. Dr. Salim Yusuf of McMaster University leads the Prospective Urban and Rural Epidemiological (PURE) Study The ambitious goal of the study is to address lifestyle questions around the underlying determinants of heart disease. The PURE study is a multi-year study of 140,000 people in 17 countries.  According to preliminary findings, there is an association between a lower consumption of total fat and an increased risk of heart disease. “Saturated fats were not harmful and perhaps even beneficial”.  

The study team is also discovering that the real problem might not be fat, but the high carbohydrate consumption.  “Fundamentally, some fats are good, some fats may be neutral, but it’s carbohydrates that are the worst thing”.  Yusuf’s advice:  “so when you eat a hamburger throw away the bun and eat the meat”.

My Low-fat Days

I grew up in the 1980s when low-fat advice was at its peak.  We were told to eat lots of grain products and other carbohydrates and to switch from animal-based to vegetable-based oils. My health-conscious mother purchased low-fat options when she could, used corn oil and soybean oil for cooking, and encouraged us to trim the fat off our meat portions.

Later, as an enthusiastic environmentalist in the ‘90s, I decided to become vegetarian, then vegan.  “Eating lower in the foodchain” was very common in my friend circle.  It seemed like a reasonable way to reduce my ecological footprint.  There was also ample information at the time about the health advantages of eating a plant-based diet. I believed what we were told – that saturated fats from milk and meat were linked to heart disease.  

My vegan days are behind me, but for many years I was eating a high-carb, low-fat diet and I wasn’t the only one. In 1970 when Nutrition Canada started recommending that we reduce our fat intake, Canadians were consuming 40% of our daily calories from fat. By 2004, we had diligently reduced our fat intake to 31%.  In the same time period, Canadians’ health has decidedly declined, with rates of obesity, heart disease and diabetes higher in the 2000s than the 1970s.

So what should we eat?

We don’t know for certain if following these “healthy eating” guidelines has worsened our health. Certainly Teicholz and others are strongly suggesting it.  And I find that troubling — as someone who eats food and has been trying to follow healthy diet advice for my whole life.  I’m also a healthcare practitioner who offers nutritional advice.  Do I send out a memo to encourage my patients to stock up on bacon?  Or do I wait until the next theory emerges to refute this one?  Does that sound cynical? Or just cautious?

I think I need to simply present this research to my patients and let them decide. And for anyone reading this with even a passing interest in nutritional research, I encourage you to pick up a copy of “The Big Fat Surprise”.  Then let me know what you decide about the bacon.