diets · fitness

The latest episode of “don’t believe what you read in the news about nutrition and dieting”

Greetings, dear readers– we at Fit is a Feminist Issue spend a lot of time and energy writing about the latest and greatest research on nutrition, physical activity, aging, wellness, etc.  We do it for a few reasons:

First, knowledge is power.  BTW, here is a very weird, but also oddly compelling, image of that saying that I found online.

The words "knowledge is power", accompanied inexplicably by pictures of two sloth-heads resting on one claw. A purple/orange sunset is in the background.
The words “knowledge is power”, accompanied inexplicably by pictures of two sloth-heads resting on one claw. A purple/orange sunset is in the background.

I think they’re sloths, but am not sure.  I welcome correction/alternative spectulation in the comments.

Back to our reasons for writing about science and nutrition, physical activity, etc.: there is a LOT of misinformation out there.  A lot-a-lot, or however you like to say/spell it.

Words:  a lot, alot, allot, lots, against a red background.
Words: a lot, alot, allot, lots, against a red background.

So, “what’s the latest misinformation?”, you may be asking.  I don’t have all day here…

Okay.  Here’s the  scoop:

The New York Times came out with the following headline this week:

NY Times headline reading, "the key to weight loss is diet quality, not quantity, a new study finds"
NY Times headline reading, “the key to weight loss is diet quality, not quantity, a new study finds”

Here’s a quote:

…a new study, published Tuesday in JAMA,…found that people who cut back on added sugar, refined grains and highly processed foods while concentrating on eating plenty of vegetables and whole foods — without worrying about counting calories or limiting portion sizes — lost significant amounts of weight over the course of a year.

The strategy worked for people whether they followed diets that were mostly low in fat or mostly low in carbohydrates. And their success did not appear to be influenced by their genetics or their insulin-response to carbohydrates, a finding that casts doubt on the increasingly popular idea that different diets should be recommended to people based on their DNA makeup or on their tolerance for carbs or fat.

The research lends strong support to the notion that diet quality, not quantity, is what helps people lose and manage their weight most easily in the long run.

Wow!  So does this mean that those who are still looking for a weight-loss program that works have found it?  Maybe this is it:  forget about calorie counting, forget about portion control, forget about balance of carbs and fats– just eat lots of fruits and veggies and avoid processed foods, and you’ll lose weight and keep it off.

Of course this is what many people think:  anyone who follows a sensible, non-junk-food diet will of course lose weight and keep it off.  And anyone whose weight is above what some set of guidelines and conventions dictates must be doing something wrong, not adhering to this modest and simple dietary advice.

Well, no. No on many fronts.  Lots of nos here.

1000 times no.
1000 times no.

Why am I saying no? Because, among other things, what the NY Times said the study said is NOT what the study said.  Here’s what the study said:

Question  What is the effect of a healthy low-fat (HLF) diet vs a healthy low-carbohydrate (HLC) diet on weight change at 12 months and are these effects related to genotype pattern or insulin secretion?

Findings  In this randomized clinical trial among 609 overweight adults, weight change over 12 months was not significantly different for participants in the HLF diet group (−5.3 kg) vs the HLC diet group (−6.0 kg), and there was no significant diet-genotype interaction or diet-insulin interaction with 12-month weight loss.

Meaning  There was no significant difference in 12-month weight loss between the HLF and HLC diets, and neither genotype pattern nor baseline insulin secretion was associated with the dietary effects on weight loss.

This study was designed to see if low-fat or low-carb diets worked better over 12 months for weight loss or improved metabolic health.  It found that neither one outperformed the other.  It didn’t say anything about embracing or eschewing calorie counting or portion control.  It didn’t test for either of those.

Here’s part of the problem.  Some studies that get null results.  In this case, researchers asked the question “is x better than y?” and got the answer “neither is better than the other”.  That’s it.  But people want to use this result to reinforce their own pre-existing views or favored hopeful views.  In this very insightful article, the authors  explain:

…it’s very tempting to misuse a null result as proof for cherished beliefs. In their discussion, the researchers did a little bit of this. They wrote in their discussion:

We conclude that when equal emphasis is given to high dietary quality for both low-fat and low carbohydrate eating plans, it is not helpful to preferentially direct an individual with high insulin secretion status who is seeking weight loss to follow a lower-carbohydrate eating plan instead of a lower-fat eating plan.

Of course, that “conclusion” is an opinion. It’s not a finding supported by this experiment. This study is a really good study, but it’s not a study of dietary quality. It’s a study of two high quality diets.

This good article cited another detailed and good article here, if you want the nitty gritty details.  Some of them include:

  • low-carb group diet had lower glycemic load than low-fat group;
  • LDL cholesterol decreased for low-fat group and increased for low-carb group;
  • low-carb group saw increase in HDL cholesterol and reduction in triglycerides relative to low-fat group;
  • resting energy expenditure decreased significantly for both groups, with no significant differences between them.

This last item is definitely not good, but we knew this already.  Dieting tends to lower your basal metabolic rate.  The other items make these diets neck-in-neck in terms of advantages and disadvantages.  Hence the “no difference” conclusion.

a scale with three circles on the left, three squares on the right, and the words "no significant difference" below.
a scale with three circles on the left, three squares on the right, and the words “no significant difference” below.

But that makes for poor newspaper copy.  Hence the wrong-information headline.

We at Fit is a Feminist Issue will be continuing to stay on the job, searching out bogus or misleading science/medicine headlines, so you don’t have to.

Just doing my job, with a girl making cake batter.

 

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