The surprising things I learned about saturated fats
The different fats in our diet are often divided into two categories: saturated and unsaturated. Meat and dairy products have a lot of saturated fat, along with unsaturated fats too. Most vegetable oils are almost entirely unsaturated.
For decades, health authorities have warned us about the negative health consequences of a diet high in saturated fats.
But does consuming saturated fats actually increase your health risk? To answer this question, I surveyed the research.
Shifting viewpoints over the years
The commonly accepted scientific view of saturated fats has shifted over the years. At first, the common recommendation would be to eat a diet low in total fat, limiting both saturated and unsaturated fats. This means, inevitably, a diet higher in carbohydrates.
Then new information emerged. It turned out that we need fat in the diet after all. And all those carbs aren’t so good for us. So authorities told us to cut down on the saturated fats in red meat and shift to vegetable sources of fat, including the most favored oil, olive oil.
Here’s a recent example of this type of advice, excerpted from the 2020 Dietary Guidelines for Americans, put out by the US Department of Agriculture:
Limit foods and beverages higher in added sugars, saturated fat, and sodium, and limit alcoholic beverages.
Notice that there’s no mention of total fat intake, only that we have to limit our intake of saturated fats.
Another new turn
But the scientific consensus on saturated fat shifted again.
In the last 15 to 20 years or so, much of the earlier research that showed the negative effects of saturated fats has been re-evaluated. Under the lens of more sophisticated statistical analysis, the relationship between saturated fat intake and poor health evaporates.
Here are some sample excerpts from more recent research.
In 2010, from the American Journal of Clinical Nutrition
Conclusions: There is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of coronary heart disease or cardiovascular disease.
In 2014, from the Annals of Internal Medicine
Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.
This perspective is now part of the guidelines for healthy eating from the 2019 American College of Cardiology and American Heart Association Task Force. Their recommendations for a healthy diet make no mention of lowering fat intake, either total fat, or saturated fat.
If your doctor simply adheres to the current medical guidelines, this is likely to be the most recent base of knowledge from which he or she will operate.
Odd twist to the story
Some scientists aren’t satisfied with the new consensus which says that eating red meat is fine and dandy after all.
For example, a group of nutrition scientists in Germany, publishing in Nutrition in Metabolic and Cardiovascular Disease in 2015 took an even deeper look at the research.
In their analysis, they further divided saturated fats into two categories:
- saturated fats from meat, whose carbon chains are invariably made of an even number of carbon atoms, and
- saturated fats from dairy products, which contain a small proportion of chains with odd numbers (usually 15 or 17) of carbon atoms.
In their view, high consumption of even-numbered carbon chains is, in fact, linked to cardiovascular disease. But eating odd-numbered chains is protective.
Most research on saturated fats had lumped these two categories together, so it wasn’t able to distinguish the subtle differences between these two sources of animal fat.
This new analysis would mean that a healthy diet would be low in fats from red meat, but would contain a reasonable amount of dairy fat, found in butter, cheese, and full-fat milk or yogurt.
These scientists aren’t alone in promoting the health value of dairy fat.
Is that the end of the story?
My guess is that there will be at least one more twist to the story line as we come to understand more fully the role that saturated fats play in our health.
That’s because the research on saturated fats tracks the intake of meat. It doesn’t differentiate between grain-fed meat and grass-fed meat. The nutrient profiles of these two sources are quite different.
To be sure, I don’t make a practice of reading the cutting-edge literature about saturated fats. As important as that topic is, it’s less than 2% of all the information I need to keep up with to do my job well.
But I predict that, if we are able to separately track those who eat lots of grain-fed meat versus those who eat lots of grass-fed meat, our view of the role of saturated fats may take yet another turn.