“PURE study challenges the deﬁnition of a healthy diet,” read the headline last week in the respected British medical journal The Lancet. Other headlines went further: Medscape wrote, “PURE shakes up nutritional ﬁeld: Finds high fat intake beneﬁcial” and STAT trumpeted, “Huge new study casts doubt on conventional wisdom about fat and carbs.”
Once again, we’re back on the nutrition roller coaster, being told that a new study has suddenly reversed everything we thought we knew about healthy eating. But has it? To help you escape that queasy roller-coaster ride, Oldways looked behind the sensationalist headlines and scrutinized the actual ﬁndings of this study. Given those anti-carb headlines, what we found may surprise you!
The PURE (Prospective Urban Rural Epidemiology) study asked 135,335 people in 18 countries to self-report what they ate at the beginning of the study. Researchers then followed up annually for about 7.5 years to learn how many had died or suﬀered various diseases. They divided the people into ﬁve groups (quintiles) according to the amount of carbohydrate, fat, and protein they ate at the start of the study, then analyzed the follow-up data and concluded that, “High carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality.”
Digging into the data, we learned that people in the poorest countries – Bangladesh, Pakistan, India, and Zimbabwe – subsisted almost entirely (up to 80.7% of calories) on carbohydrates, which the researchers themselves characterized as almost certainly reﬁned grains like white rice. This group – with the poorest health outcomes – ate a diet with a makeup something like this:
That’s the diet researchers cautioned against following. In their conclusions, by way of contrast, the researchers recommended instead a diet that contains 50-55% carbohydrates, 35% fat, and (by diﬀerence) 10-15% protein. Does this “cast doubt on conventional wisdom?” Does it “challenge the deﬁnition of a healthy diet?” We say no.
There is an uncanny resemblance between the PURE recommendations and the typical macronutrient (fat, carbohydrate, protein) proportions for the Mediterranean Diet. The Med Diet, in fact, tends to be a tad higher in healthy fats, and a bit lower in carbohydrates. The Mediterranean Diet is one of the most researched and documented diets on the planet, the gold standard for healthy eating. That makes it hard to say that PURE has come up with something new and diﬀerent.
What about the US Dietary Guidelines? The PURE authors stated, “Global dietary guidelines should be reconsidered in light of these ﬁndings.” Yet as the charts above show, there’s a fairly solid overlap between the PURE scientists’ recommendation and the ﬂexible ranges in the US Dietary Guidelines.
“Put down the carbs and pick up the bacon” was the common takeaway in some stories about the PURE study, as if the study were recommending that everyone adopt a low-carb Atkins-style diet. But that’s not what the study was saying at all. The PURE recommendations and Atkins look nothing alike:
Here’s what the PURE study was really saying. We’ll paraphrase, to bring you the real message of this study. “Really poor people who can’t aﬀord much protein, fat, fruits, vegetables, and whole grains tend to subsist on white rice, white noodles, and white bread. This kind of diet is linked with dying younger and contracting more disease. It would be better if we all eat a diet that contains moderate amounts of carbs, proteins and fats.” That message doesn’t stand conventional wisdom on its head at all – it mirrors long-standing advice.
Oldways’ Takeaway Advice
The bottom line is that what we knew to be true about healthy eating yesterday is still true today, so we’ll leave you with three pieces of advice:
- The experts still agree. In November 2015, Oldways brought together leading nutrition experts representing views from Paleo to Vegan at our Finding Common Ground conference. They all agreed that focusing on quality and variety is the key to eating well. This means choosing high-quality meat, ﬁsh, and/or beans and other protein sources instead of living on bologna and bacon; eating whole grains (especially intact grains) instead of reﬁned grains and added sugars; enjoying a range of fruits and vegetables; and favoring the heathy fats found in nuts, avocados, ﬁsh, olive oil, and other foods.
- Use Carb Common Sense. Everybody needs carbohydrates. Avoiding carbs makes no sense – especially when you remember that fruits and vegetables are also made up primarily of carbohydrates. Check out the Oldways Whole Grains Council’s easy guide to Carb Common Sense, to steer smoothly through your carb choices.
- Eating should be a pleasure, not a math exam. We used charts and numbers to prove a point today, but we are not recommending you count grams of this or percents of that as you pick the foods you eat. Traditional diets, like those Oldways champions, can vary widely in their makeup and still support good health. Look for the highest quality you can aﬀord (see #1 and #2), and the numbers will take care of themselves.
If you’d like to read more about the PURE study’s shortcomings, we recommend these two articles by David Katz (in the Huﬃngton Post) and by James Hamblin (in The Atlantic). David and Jim are two of the leading voices of sanity and common sense in the world of nutrition.
Cynthia Harriman, Director of Food & Nutrition Strategies