Can Whole Milk Keep You Thin?
A slew of recent research suggests that the old advice to choose low-fat dairy may be wrong. High-fat dairy products appear to help keep you leaner. Nutrition Diva takes a closer look at this apparent paradox.
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Hypothesis #1: More Fat = More Filling
One possibility is that high-fat dairy products increase your satiety after a meal. Meals that are higher in fat are more slowly digested and absorbed, which means that you go longer before you start to get hungry again. If you pour whole milk over your cereal instead of skim milk, for example, you might add 50 to 100 calories to your breakfast. However, the increased satiety might mean that you're not as likely to need a snack mid-way through your morning. If you add 100 calories to breakfast but then avoid a 250 calorie donut at 10am, you're 150 calories ahead of the game.
Not only does it keep you full longer, but fat also tends to be more satisfying in the moment--which, believe it or not, could help you eat less. For example, I can think of few things in life that make me sadder than reduced-fat cheese. I'm much happier eating two or three crackers spread with a triple-cream Brie than 10 crackers topped with reduced-fat cheddar. I think of this as the "savor and stop" effect.
Hypothesis #2: Higher Fat Means Lower Blood Sugar
A somewhat related possibility is that the higher fat content in full-fat dairy products helps keep your blood sugar steadier. Adding fat to a meal slows down the speed at which your blood sugar rises and falls as you digest your food. This slower rise and fall in blood sugar may help keep your appetite and fat-storage hormones on a more even keel, reducing the risk of diabetes as well as weight gain.
See also: What Is High Glucose?
Hypothesis #3: There's a Magical Ingredient
Perhaps the most fun thing to think about is that there is some sort of magical ingredient in dairy products that promotes weight loss. (I mean, do we ever get tired of magical ingredients that promote weight loss?)
There has been quite a bit of research on calcium's ability to enhance fat loss. However, this is probably not a factor here because high-fat and low-fat dairy have about the same amount of calcium. If anything, low-fat dairy products have a bit more calcium.
Milk from grass-fed cows is higher in these potentially beneficial compounds than milk produced on industrial feed lots.
A more likely candidate would be something in dairy fat itself. There are number of fatty acids that could plausibly play a role. Conjugated linoleic acid. for example, has become a popular weight loss supplement, mostly on the strength of some early animal research. Research on CLA to promote fat loss in humans has been disappointing but this doesn't seem to have made a dent in sales. In any case, the amounts of CLA in dairy products are relatively small, making it even less likely that CLA is a major player in this story.
Butyric acid and palmitoleiic acid are other dairy-based fatty acids with potential to regulate fat metabolism and weight. Or, we could be seeing the combined effect of several of these compounds.
See also: Is Grass-Fed Beef Better For You?
It's too soon to say whether these fatty acids--alone or in combination--are responsible for any of the observed effects of high-fat dairy consumption. But, for what it's worth, milk from grass-fed cows is generally higher in these potentially beneficial compounds than milk produced on industrial feed lots.
What to Do With This Research?
All this is very interesting for nutrition researchers, of course. But where does this incomplete and preliminary information leave you? Should you switch from low-fat to high-fat dairy products? Potentially, yes--but with caution. Simply switching from skim milk to whole milk will add calories to your diet, which, in the absense of other adjustments, can lead to unwanted weight gain.
No one food or nutrient is a magic bullet for weight loss. It's how you put it all together that counts.
Here are a few tips:
Work the satiety angle. If you currently eat low-fat yogurt, cottage cheese, or cheese, try replacing these with the full-fat versions and see if it helps you cut down on between-meal snacking.
Remember to savor and stop. Treat yourself to real cream in your coffee, if you like, but have one cup instead of three. The idea is to upgrade quality but decrease quantity.
Consider the source. Watch out for full-fat dairy foods that are also high in sugar or refined flour--such as creme brulee or cheese-stuffed pizza crust. While butterfat may not be the villain it's sometimes made out to be, I think that the combination of fat and sugar and/or white flour can do quite a bit of damage.
One size does not fit all. Although eating more full-fat dairy products doesn't seem to increase risk of obesity or heart disease in the general population, your doctor or nutrition professional can help you decide what is right for your particular situation--especially if you are already overweight or have risk factors for heart disease.
Share your questions and comments below or on the Nutrition Diva Facebook page. I always love to hear what you're thinking (and eating)!