In light of the recent study published in The Lancet, you may be asking yourself if you should ditch your low carb diet altogether.
And how can you not when headlines such as…
…scream at you from your computer screen?
I’m here to tell you – not so fast. As with literally anything that comes out in the mainstream media today, you have to really look at the content – not just the headlines. This is imperative in the age of clickbait and attention-grabbing snippets.
Also, if you’ve been interested in nutrition for any amount of time, I’m sure you’ve realized by now that studies claiming one particular style of eating will kill you come out at least a couple of times a year.
There was a similar issue with coconut oil this time last year. Everyone’s favorite fat was all of a sudden dangerous and deadly. We wrote a whole article on the debacle. Check it out here.
(We also wrote a whole series of articles on coconut oil. They’re worth the read.)
Low carb diets, such as Paleo, Keto, and Atkins have been popular for years, but may perhaps be at an all-time high now. So as you can imagine, when this study came out claiming that these diets may be fatal, people were worried.
Before we lose our heads, though, we need to take a deeper look at the study.
Let’s go ahead and dive into it.
Table of Contents
What’s The Lancet Study Claim?
The stated purpose of this study was to examine the relationship between carbohydrate intake and mortality. The researchers looked at over 15,000 adults between the ages of 45-64. These adults completed dietary questionnaires between 1987 and 1989 when enrolling in the Atherosclerosis Risk in Communities study. They combined this data with carbohydrate intake reports from seven other prospective studies through a meta-analysis.
After a 25 year follow up, they examined the amount of deaths across those study populations. They specifically looked at carb intake and mortality, and found that the people who received 50-55% of their energy from carbs had the lowest risk of mortality.
Subjects that had <40% and >70% carb consumption had greater mortality risk. They also found that risk of mortality increased when animal-derived fat or protein were switched out for carbs. Mortality lessened when these substitutions were plant-based.
“Both high and low percentages of carbohydrate diets were associated with increased mortality, with minimal risk observed at 50–55% carbohydrate intake. Low carbohydrate dietary patterns favouring animal-derived protein and fat sources, from sources such as lamb, beef, pork, and chicken, were associated with higher mortality, whereas those that favoured plant-derived protein and fat intake, from sources such as vegetables, nuts, peanut butter, and whole-grain breads, were associated with lower mortality, suggesting that the source of food notably modifies the association between carbohydrate intake and mortality.”
What’s all of this mean?
Chances are, if you’re reading this blog, you’re somewhat interested in a low carb approach to eating. And as you can piece together, this study says that this style of eating might just make it more likely that you’ll die.
Before we throw up our hands and start shoving 50-55% of our daily calories worth of carbs in our faces, let’s break down this article a bit.
First off, if you’re a follower of the Paleo diet and think that you need to stop eating this way ASAP, hold up…
This study documented that the low-carb group ate a diet with a lower average intake of fruits and vegetables.
Now, if you’re the Paleo person who eats 90% bacon, you might want to reconsider. But if you’re one of our readers, you know that we advocate for eating majority fruits and vegetables with high-quality protein and healthy fats as supporting roles.
So – if you are a fruit and veggie lover like myself, you’ve pretty much already ruled yourself out of this (somewhat flawed) data applying to you.
To go along with that, there’s a lot of well-researched rebuttals to this argument.
Chris Kresser has been a proponent of the low carb approach for a long time, so I knew that he would have some thoughts on this study.
I wasn’t disappointed. I definitely recommend that you read his rebuttal in full.
Kresser lays out seven reasons where this study comes up short. I’ll outline some of his prominent points here:
Correlation doesn’t equal causation
In these studies, the data used were observational.
As Kresser explains, “It’s not an experiment where they are directing a specific intervention (like a low-carb diet) and making things happen. Instead, the researchers are just looking at populations of people and making guesses about the effects of a diet or lifestyle variable.”
To reach a conclusion, the studies would need to be a randomized control trial where variables can be controlled for and a solid conclusion can be found.
Food Frequency Questionnaires Were Used
A food frequency questionnaire is a series of questions that gleans information about the type and amounts of food people eat over a certain period of time. Food frequency questionnaires (FFQs) are notorious for not being 100% accurate. The authors of this study even admit this shortcoming.
In this particular study, the participants were asked to report the food they ate over the course of two different 6 year intervals. So the total time period researchers looked at covered 25 years, but the food frequency questionnaires only assessed 12 of those years.
In Kresser’s article, he points out many examples of why FFQs can be unreliable data. But if you just think about it for a second, if you were asked to report your food intake last month – or even just last week – it would be hard to be even 85% correct (unless you have a steel-trap of a memory.)
You Can’t Control For Everything
So many variables can affect our health. And, unfortunately, in nutritional studies, it is really difficult to control for every single factor that may impact the eventual outcome. Factors such as lifestyle, genetics, habits, food/air/water quality will all have an affect on health outcomes.
Kresser points out that The Lancet study made attempts to only look at data that controlled for at least three of the following factors:
- Smoking status
- History of cardiovascular disease
- Family history of cardiovascular disease
But obviously, only controlling for three of these still leaves lots of room for the other factors to play a role in the results.
Quality and Quantity
This is where Kresser shows his nutrition philosophy. He argues that when it comes to an issue like carbs – the distinction is not in how much we eat, but rather what kinds of carbs we eat.
He suggests that for nutrition research in general, we should stop focusing on the quantity, and turn our attention towards the quality.
This study did not focus on the quality, and just separated participants into groups based soley on their total carb intake.
There Is No “One Size Fits All” Macronutrient Amount
If only it were that easy, right?
Kresser makes the point that throughout history, there has never been an ideal carbohydrate intake amount. This has varied greatly between populations – with some ancestral populations consuming high carbohydrate amounts and some more on the lower end of the spectrum.
Despite the difference, these populations survived and even thrived. They also didn’t have high instances of the chronic diseases like we see today.
The Baseline Low Carb Group
One last important point to call out about this study has to do with the baseline low carbohydrate group of participants. Dr. Bret Scher pointed out that the this group of people overall had a heavier body weight, smoked more, had a higher percentage of diabetics, and did not report exercising.
If you know anything about health, these factors would most definitely affect health outcomes. It is crazy to think that we can point solely to the diet and say definitively that it is the only aspect that’s affecting mortality.
To be honest, I’m not particularly worried about this study. I believe that if you eat a varied, well-balanced diet comprised mainly of vegetables, fruit, high-quality protein, and healthy fats…if you drink lots of water…if you exercise and move your body in ways you enjoy…if you manage your stress appropriately…if you do these things, you are going to be just fine.
What are your thoughts? Will this change how you approach your diet? I’d love to know.
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