Q: Studies have shown that some meats increase heart disease risk. Is saturated fat the culprit?
A: Saturated fat may not be the main problem. For instance, red meat also contains other potentially harmful nutrients, such as a certain type of iron that may raise the risk of type 2 diabetes. Processed meats have sodium, which increases blood pressure and risk of stroke. Low-fat hot dogs and processed deli turkey have less saturated fat than a steak, for example, but also contain, on average, up to four times as much sodium per gram. Research from our group and others shows that processed meats, such as bacon, bologna, deli meats and sausages, pose a risk of heart disease and type 2 diabetes that’s two or three times as high as the risk posed by unprocessed meat, even when the -saturated-fat content is the same.
So saturated fat alone is not a useful metric for making a healthy choice. Consider a typical deli sandwich made with low-fat processed meat. It may contain little or no saturated fat. But processed meat is typically very high in sodium. Processed cheese is also high in salt. It’s even worse if the meat and cheese are served on refined white bread, loaded with refined carbohydrates. In terms of health risks, that sandwich is a cardiovascular bomb. You’d be better off eating a home-cooked steak. Of course, the best choices would still be conventionally healthy options such as fish, nuts, vegetables, fruits and whole grains.
Q: What about the epidemic of overweight and obesity? Are fatty foods more likely to make people fat?
A: That’s what we once thought. We also thought that high-fat diets raised the risk of heart disease. But evidence has proved that the proportion of total fat in a person’s diet has no effect on heart disease. Growing evidence indicates that this is also true for obesity. Dietary fat doesn’t make people fat. When we studied how specific foods related to weight gain over time, the main culprits were starches, such as potatoes, refined carbohydrates and sugars—in other words, poor-quality carbohydrates.
Q: Is saturated fat more dangerous for some people than others?
A: For someone who is young, lean and active and whose only risk factor is elevated LDL, reducing saturated fat might be helpful as long as it’s replaced with polyunsaturated fats, such as vegetable oils. But more and more Americans are overweight and sedentary. They typically have low HDL, insulin resistance and elevated triglycerides, a combination of risk factors called metabolic syndrome. Refined carbohydrates are a bigger risk for them than saturated fat, especially from dairy foods, which may actually improve metabolic syndrome. For people with metabolic syndrome, a focus on reducing consumption of potatoes, sugars, white bread and other refined carbs is most important, together with increasing consumption of healthy foods such as fish, fruits, vegetables, nuts, whole grains, vegetable oils and moderate amounts of dairy.
Q: If we toss out the focus on saturated fat, what should the message be?
A: I want to be clear. I’m not saying that saturated fat is good for you. I’m saying that our historical emphasis on cutting back on saturated fat has led to some bad choices. We should focus our recommendations on foods, not single nutrients like saturated fat. Last year Simon Capewell, DSc, a professor of clinical epidemiology at the University of Liverpool, and I drew up a list of dietary priorities that could reduce heart disease deaths by half in the U.S. and around the world. Limiting saturated fat doesn’t make the cut, because we don’t think that on its own it offers much benefit. We estimate that getting Americans to add two servings of nuts a week to their diets would reduce cardiovascular mortality by 11 percent. Replacing refined grains and starches with a serving of whole grains every day would decrease heart-related deaths by an additional 10 percent. Adding an extra serving of fruits and vegetables a day would reduce heart disease mortality by 15 percent more. Those simple changes would make a far bigger dent in heart disease than anything we could expect from reducing saturated fat.