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Wednesday, August 18, 2010

Low-Carb Versus Low-Fat

Every so often, one of the journals will publish a study trying to compare a low-carbohydrate diet such as Atkins to a low-fat diet.

Last week's Annals of Internal Medicine had a comparison of patients following either diet for two years.  Weight loss at two years was about the same, but on a few parameters, such as change in HDL, the low-carb diet was superior.

There are a few problems with the study.  First off, low-fat was defined as 30% or fewer calories from fat.  30%?  Really?!  I would hardly call that low-fat.  Also, there's nothing stating what people actually ate.  When people in previous studies have been told to consume 30% fat, their fat intake actually hovers around 36%.  That's definitely not low-fat. 

If you look at Dean Ornish's studies on low-fat diets in patients with coronary disease, the fat content prescribed is 10%, and those patients had overall regression of their coronary disease and improvement in their lipids, even in the absence of statin medication.  Perhaps 10% fat is challenging for most to obtain, but I think 30% is way too high to be called low-fat.

Look closely at the patient populations of the low-fat versus low-carb studies such as this one.  They're overweight but remarkably healthy.  They don't have diabetes and aren't on statin medications for cholesterol.  Their blood pressure is under pristine control.  And of course they don't have coronary artery disease.  These are characteristics vastly different from the general American public, and a huge departure from the typical patient whom I see in my office.

Here's my problem with the concept of the Atkins low carbohydrate diet:  We weren't designed to eat that way.  Think back to our predecessors who dwelled in caves.  They didn't eat huge quantities of meat.  And admittedly, they weren't vegans either.  They ate the little meat that they could hunt down, catch, and kill.  There was no McDonald's drive thru or a supermarket meat counter to buy a prepared slab of meat.

I strongly believe that a plant-based diet is the best option for health.  Plant-based diets reduce risk of coronary disease, lower blood pressure and cholesterol, help to manage and reduce the risk of diabetes, lower body mass, and reduce the risk of many cancers.


celine said...
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Jason said...

Thanks for pointing this one out - I have to keep reminding myself that as hard as it is to remind activists to read the fine print, as it were, in medical studies, it's a million times harder to remind the general public, and it's costing us.

Change is hard, and the "what you're doing is the right thing (even if it hasn't worked for you for years)" message is an easy sell. I'm bookmarking this for when the report gets filtered a few times through the media and then comes back to me in an outreach scenario. Cheers!

Marcia said...

I just caught up on a bunch of posts.

I really enjoyed reading about your Ironman experience - amazing! I cannot imagine exercising at that level for almost 15 hours.

I also read your June post about difficulty getting into the ocean. I've been training for my first (sprint) triathlon and I *so* know what you are talking about. The waves have been pretty rough here the last few weeks. I've been scared like crazy. My first time in the pool in 20 years was 6 weeks ago and my first swim in the ocean ever was shortly after.

My race is Sunday, and I've been suffering on my runs, which is my strongest part. I injured my leg training for my last half marathon (so I'm trying to relearn how to run), and now I've tweaked my knee. I'm also looking for the happy place where I can stay fit and my 40-year old body parts don't ache.

Just wanted to let you know that you are truly inspirational.