We have the answers to these questions, kept in the shadows impressively well by the peddlers of pepperoni and bacon.
- The range of saturated fat intake examined is pretty narrow. In the first meta-analysis, the top and bottom of the range often differed by only a few percentage points, and even the bottom of the range was above current recommendations. The later meta-analysis compared the top third of the population to the bottom third and, again, the difference was small.
- To the extent saturated fat intake has gone down over time in the U.S. – and it hasn’t gone down much – it has mostly been replaced by sugar and refined carbohydrates.
A generally neglected consideration is that overall diet quality was comparably bad at the “extremes” of the rather narrow saturated fat range observed. That’s about what we would expect if the main alternatives to saturated fat from burgers, pizza and ice cream were refined carbohydrate and sugar from soda cookies, fries and donuts.
The available evidence suggests that is exactly what happens. Data from both the U.S. Department of Agriculture and the Centers for Disease Control and Prevention shows that animal fat intake in the U.S. has stayed fairly constant over recent decades, while sugar intake, refined carbohydrate intake and total calories have gone up.
The crucial question that neither meta-analysis answered is this: How does variation in saturated fat intake affect rates of heart disease when the alternatives to saturated fat calories are assessed? A 2015 paper provides the answer. In roughly 125,000 people over nearly 30 years, heart disease rates went from bad to even worse if trans-fat replaced saturated fat, stayed the same when sugar and refined carbohydrates replaced saturated fat and declined significantly when saturated fat calories were replaced with either calories from whole grains or calories from unsaturated fats coming from nuts, seeds, olive oil, avocado, fish and seafood. A more recent study of comparable size and methods appended this: Rates of heart disease go up when more of total dietary fat is saturated, and go down as more of total dietary fat is unsaturated.
Shockingly at odds with those making a case for saturated fat, what all of these data seem to indicate is just what both science and sense suggested all along: A diet made poor by an excess of saturated fat from the usual sources – beef, processed meats, fast food and processed dairy – is almost exactly as bad for health outcomes as a diet made poor by an excess of sugar and refined carbohydrate from the usual sources. There is more than one way to eat badly – and we seem dedicated to exploring them all.
It is certainly true that saturated fat is not, and never was, the one and only thing wrong with our diets. It’s also true that not all saturated fats are created equal. But those are not the propositions that are being peddled. The misguided premise is that we must choose the one, true dietary scapegoat from either saturated fat or sugar.
The fundamentals of a genuinely healthful diet are clear, supported by vast and diverse evidence and a matter of global consensus. They translate into dietary patterns of wholesome foods in any of various sensible combinations that are inevitably low in added sugar, refined carbohydrate and saturated fat alike. Applied routinely, they could add years to lives, and life to years – and benefit the planet too.