Monday, January 18, 2010

Whole Milk or Low Fat? The Answer's Not Clear.

Whenever the professional nutritional community discusses the use of dairy products, they always recommend using low-fat or even fat-free milk and dairy products. Courtney Helgoe argues that this advice may be totally wrong in an article for Experience Life Magazine.

Her argument is interesting, although not completely convincing. She highlights a major problem, one that I constantly complain about, that there are far too few good studies about the role of an individual food in the totality of our diets and many of the ones that exist are not as comprehensive as people make them out to be.

However, what makes her argument less than it could be is that she keeps talking about low-fat diets interchangeably with diets that use low-fat milk. There is no reason whatsoever to think that the people who take whole milk out of their diets are getting sufficient - or way too much - fat from other sources.

The entire article is interesting and well-researched and I recommend reading it with that caveat in mind.

Except. If the article were simply about the fat content of milk, I probably wouldn't bother to critique it at all. This is a blog about lactose intolerance. What jumped to my eye was a statement about the lactose in milk that I think is just plain wrong.
It's also likely that one will drink much more skim milk than whole (or eat more low-fat yogurt, fat-free sour cream, low-fat ice cream, etc.) for three reasons:

1.It generally takes larger servings of low-fat foods than full-fat foods to switch on our bodies' satiety signals.
2.There’s a psychological tendency to feel that because we're "being good" by eating these low-calorie, low-fat products, we are justified in "making up for it" by eating more of them — or more of something else.
3.Low-fat foods don’t keep us satisfied for as long and may also destabilize blood sugar, so we're likely to experience cravings to want to eat again sooner.

This last point deserves some explanation: Low- and no-fat dairy delivers more fast-absorbing lactose to the bloodstream, and more potential for corresponding insulin spikes and resultant sugar cravings. Full-fat dairy doesn’t have this effect. "The proportion of lactose decreases with every increase in milk-fat content," [Anne Mendelson in Milk: The Surprising Story of Milk Through the Ages] explains. So relative to skim milk, "heavy cream contains only minute amounts."

It's true that the lactose content of dairy products gets lower as the fat content gets higher. But the difference is hardly huge. "Minute" is the wrong word to use.

Check my Big List of Lactose Percentages. Heavy cream, which I have listed as whipping cream, has 60% of the lactose of skim milk. That's a difference, but not as significant as the quote would make out.

Lowering fats in your diet is still probably a good thing. If the only difference you make is to eat low-fat dairy products and you think that's sufficient you're wrong. Nor will taking out fats work if you devour tons of empty sugar calories. A good diet is a balance across all foods, all categories, all meals.

See table below for lactose percentages in fluid milks.



Fluid MilksRangeAverage
Regular Whole Milk3.7-5.1%4.8%
2% Lowfat Milk3.7-5.3%4.9%
1% Lowfat Milk4.8-5.5%5.0%
Nonfat (Skim) Milk4.3-5.7%5.2%
Chocolate Milk4.1-4.9%5.0%
Half-and-half4.0-4.3%4.2%
Light Cream3.7-4.0%3.9%
Whipping Cream2.8-3.0%2.9%

1 comment:

  1. Great info, also I think the choice of milk depends on what you are trying to achieve. More of I like your blog and thanks for sharing it. I also found homogenized vs whole milk comparison very helpful.

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