You know how butter is good for you again? Or at least, not bad for you? Not so fast. If you’re reading this, poised mid-spread while preparing a delicious buttery sandwich, then put down the butter knife and step away from the counter. A new study from the Harvard TH Chan School of Public Health says that saturated fats and trans fats, including those in butter and meat, will kill you.
And it’s a big study, following 126,000 people over 30 years. The major finding was that replacing saturated fats with polyunsaturated fats like olive oil reduces your chances of death. "This study documents important benefits of unsaturated fats, especially when they replace saturated and trans fats," said lead author Dong Wang.
Because the study was so long and so big, useful long-term conclusions can be drawn from it. To get an idea of the scale, during the 3,439,954 person-years of follow-up, 33,304 of the participants died. The study controlled these deaths for other risk factors, and then compared the total fat and total carbs in diets.
The results show that, in people who ate less butter, lard, and red meat and instead focused on vegetable oils like olive, canola, and soybean had death rates 11% to 19% lower than those who kept eating the saturated fats. Saturated fats also correlated positively with increased risk of Alzheimer’s, Parkinson’s, as well as respiratory disease.
Further, replacing 5% of saturated fat calories with something like olive oil reduced the chance of an early death by an amazing 27%. Even replacing butter, lard, and meat with carbs was beneficial, although much less so than switching to polyunsaturated vegetable fats.
So what are we to do? We have studies telling us that butter is healthier than the bread you spread it on, and now this study, which says the opposite, both of which appear well researched. What do you believe? Even the study’s lead author Dong Wang agrees it’s baffling. "There has been widespread confusion in the biomedical community and the general public in the last couple of years about the health effects of specific types of fat in the diet," he says.
The one thing that seems constant across all of these studies is that the Mediterranean diet is good for you. It also happens to be delicious, easy to prepare, and, if you live in the right places, where the foods are readily available, then it’s cheap, too. In fact, the only thing that might possibly count against the Mediterranean diet: no delicious butter.
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