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Wed February 12, 2014
The Full-Fat Paradox: Whole Milk May Keep Us Lean
Originally published on Tue February 18, 2014 10:52 am
I have to admit, I melt at the creaminess of full-fat yogurt.
It's an indulgence that we're told to resist. And I try to abide. (Stealing a bite of my daughter's YoBaby doesn't count, does it?)
The reason we're told to limit dairy fat seems pretty straightforward. The extra calories packed into the fat are bad for our waistlines — that's the assumption.
But what if dairy fat isn't the dietary demon we've been led to believe it is? New research suggests we may want to look anew.
Consider the findings of two recent studies that conclude the consumption of whole-fat dairy is linked to reduced body fat.
In one paper, published by Swedish researchers in the Scandinavian Journal of Primary Health Care, middle-aged men who consumed high-fat milk, butter and cream were significantly less likely to become obese over a period of 12 years compared with men who never or rarely ate high-fat dairy.
Yep, that's right. The butter and whole-milk eaters did better at keeping the pounds off.
"I would say it's counterintuitive," says Greg Miller, executive vice president of the National Dairy Council.
The second study, published in the European Journal of Nutrition, is a meta-analysis of 16 observational studies. There has been a hypothesis that high-fat dairy foods contribute to obesity and heart disease risk, but the reviewers concluded that the evidence does not support this hypothesis. In fact, the reviewers found that in most of the studies, high-fat dairy was associated with a lower risk of obesity.
"We continue to see more and more data coming out [finding that] consumption of whole-milk dairy products is associated with reduced body fat," Miller says.
It's not clear what might explain this phenomenon. Lots of folks point to the satiety factor. The higher levels of fat in whole milk products may make us feel fuller, faster. And as a result, the thinking goes, we may end up eating less.
Or the explanation could be more complex. "There may be bioactive substances in the milk fat that may be altering our metabolism in a way that helps us utilize the fat and burn it for energy, rather than storing it in our bodies," Miller says.
Whatever the mechanism, this association between higher dairy fat and lower body weight appears to hold up in children, too.
As we reported last year, a study of children published in the Archives Of Diseases in Childhood, a sister publication of the British Medical Journal, concluded that low-fat milk was associated with more weight gain over time.
"It really surprised us," study author Mark DeBoer, a pediatrician at the University of Virginia, told us.
So, where does this leave us, the rule-followers, who have complied with the skim-milk-is-best edict?
Well, opinions differ. The recommendations that led to the fat-free dairy boom were, in part, born out of concerns about cholesterol.
Whole-milk dairy products are relatively high in saturated fat. And eating too much saturated fat can increase the risk of heart disease. So many experts would agree that adults with high cholesterol should continue to limit dairy fat.
But it's also becoming clear that there are benefits to full-fat dairy, too, at least for some consumers.
As we've reported, in addition to the body weight association, organic whole milk contains beneficial omega-3 fatty acids.
It's unclear whether more people are opting for whole milk products. Though nonfat and low-fat still dominate dairy sales, the organic sector is experiencing an uptick in whole-fat sales.
"We definitely in the last few years are seeing a trend toward the whole-fat products," George Siemon, CEO of farmer-owned Organic Valley, told us. His company's sales of whole-fat milk are up 10 percent, he says. And sales of skim milk have trailed off. Also, there's been a boom in butter sales.
So, stay tuned. Though it's a sounds-too-good-to-be-true finding, researchers are continuing to investigate how dairy fat may help people control their weight.
STEVE INSKEEP, HOST:
At this time, when we're constantly told to watch what we eat, it's almost gospel that skim milk and low-fat yogurts are better for you. But if you looked at some parts of the dairy industry, you'd see that in places like the organic markets, sales of full-fat dairy are up. Maybe organic buyers had the right instinct. Two new studies have a counterintuitive finding: People who make a habit of consuming high-fat dairy tend to be leaner. NPR's Allison Aubrey reports.
ALLISON AUBREY, BYLINE: Breakfast time can be noisy at the Cullaty home in Charlottesville, Virginia.
MARTHA CULLATY: It's really crazy in our house between seven and eight.
(SOUNDBITE OF BLENDER)
AUBREY: No, that's not a chainsaw. That's a blender. And like a lot of families, the Cullatys love smoothies. So, what did they toss in today?
CULLATY: It was full-fat yogurt, a banana and some ice.
AUBREY: You won't find fat-free in this home. Full-fat yogurt is the norm. Martha Cullaty says she and her husband and their two kids like the taste better.
CULLATY: It just tastes richer and not watered-down.
AUBREY: And she thinks the fat naturally found in dairy is good for her kids, especially since they don't eat much meat.
CULLATY: They're both fairly thin and very active. And so I didn't see any need to eliminate those calories.
AUBREY: Cullaty is not alone. Increasingly, moms like her like the idea of eating whole foods, unprocessed. If you take the fat out of milk, what else are you losing? Now, many researchers say this is a good question, and especially since several new studies have found - perhaps surprisingly - that people who eat higher fat dairy tend to be leaner than people who stick with skim products.
GREG MILLER: I would say it's counterintuitive.
AUBREY: That's Greg Miller, a scientist with the National Dairy Council. He says consider new findings from a big independent study. Swedish researchers analyzed the eating habits of a few thousand middle-aged men. They found the men who ate fatty butter and high-fat milk had lower rates of obesity by the time they reached their 50s and 60s, compared to the men who seldomly or never ate cream, butter or fatty milk.
MILLER: This finding is consistent with a lot of other observational studies that show that higher dairy fat intake is associated with reduced body fat.
AUBREY: So, the question is: Why might this be? Well, it's possible that high-fat dairy makes people feel full, so they eat less. Or, Miller says, maybe it's something more complicated.
MILLER: There may be bio-active substances in the milk fat that may be altering our metabolism in a way that helps us utilize that fat and burn it for energy, rather than storing it in our body.
AUBREY: Now, clearly, there needs to be more research before folks are encouraged to eat more dairy fat. After all, the original recommendations to limit it were driven by concerns about cholesterol. And most experts would say that adults with high cholesterol should stick with low-fat alternatives. But how about children? The American Academy of Pediatrics recommends that kids switch to low-fat dairy at age two. But pediatrician Mark DeBoer says this high-fat dairy paradox has been documented in children, too. He studied the milk habits of some 10,000 kids in the U.S. and found that those who drank low-fat milk were more likely to be heavy.
MARK DEBOER: The thing that struck us the most - first of all, the American Academy of Pediatrics recommends that children drink low-fat milk specifically so that they won't gain weight over time. But when we looked at what happened over time, among those who were drinking the low-fat milk, even those who started normal weight were more likely to become overweight than those who were drinking higher-fat milk.
AUBREY: That's actually quite - it sounds surprising.
DEBOER: It really surprised us at the time.
AUBREY: So, given all of the recent evidence, some experts say it might be best to revisit the assumption that fat-free dairy is always best. Allison Aubrey, NPR News. Transcript provided by NPR, Copyright NPR.