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Could your low-carb diet be killing you?

Could your low-carb diet be killing you?

Could your low-carb diet actually be killing you? I know it’s kind of a terrifying thought considering how many people have been using low carb and keto-style diets for weight-loss. Not to mention haven’t all the internet gurus been touting how amazing keto and low carb diets are? 

“They have X, Y, Z health benefits and can probably make you poop rainbow sherbert in the process!” 

Well, I hate to burst your bubble but low carb diets offer nothing special in terms of health benefits, there is no rainbow sherbert poops – only constipation, and the evidence shows they are no more effective at weight-loss than any other diet. I know, Craig the IG model has been lying to you. Nonetheless, you might actually enjoy low carb diets because you have sociopathic tendencies and dislike carbs OR you have a legit medical reason to avoid carbs such as being celiac. And that is totally OK, but you might want to just make sure you are taking the right approach. 

Get your learning hat on! 

A study completed by Mazidi and friends in 2019 showed that low-carb diets might actually be harmful. The purpose of their study was to specifically look at the long-term effects of low-carb diets. You see, most nutrition research around diets tends to be short-term – usually 8-12 weeks, maybe 1-2 years if we are lucky. What might be assessed in that time is things like blood pressure, cholesterol, blood sugars, and weight. Which there is nothing wrong with and we can certainly make inferences and extrapolations based on this data but to really know if an intervention or dietary pattern actually contributes to bad things like heart attacks and death it takes a bit more time. Especially with nutrition! This is because humans don’t eat the same thing every day. The composition of our diets will follow a trend but our macro- and micro-nutrient compositions will vary from day to day.

Now Mazidi and pals were focused on low carb diets because generally when humans decide to go on a low carb diet they tend to substitute the removed carbs for animal fats and proteins. Now one wouldn’t think this is a problem but we have a pretty solid body of evidence that shows diets higher in animal proteins and fats tend to have a higher risk of heart disease and death. In fact, replacing animal proteins with plant-based proteins can reduce an individual’s risk of heart disease and death. The reason for this is that animal fats and proteins tend to contain more saturated fats which are no bueno. They cause our LDL or bad cholesterol to increase which can lead to clogged arteries! 

So Mazidi and friends’ specific objective was to know if there was a relationship between low carbohydrate diets and death or death from a specific cause. To answer this question they looked at a large sample of the US population, 25,000 people in total. On top of that, they looked for other studies that had been done assessing the potential long-term risks of low-carb diets and through magic and wishes they combined the data of all those studies together in order to add to the robustness of the data set from their sample population. Fortunately, these other studies had been done elsewhere in the world, therefore, increasing the applicability of their results to other populations outside of the US. I know just like how the Earth is not flat, there are people that live outside of ‘Merica! 

Anywho, Mazidi’s group found some interesting results over the 10+ years worth of data they collected. First off out of the 25,000 person sample they pulled ~3400 people had died by the end of the 12-year period. That is nearly 15% of the population they originally collected, and while sad, when looking at an outcome like death this is a good thing as we have a lot of data to work with. What they found was that people who followed low-carb dietary patterns had a significantly increased risk of heart attacks, strokes, cancer, and death from any cause. They found similar results in their combined data set from multiple other studies.    

So do we believe this data? Could it be true?! Has IG Craig led us astray all this time?

Well like any good scientist we will forever say that more research is needed. However, this was a relatively well-done study. Yes, it has some shortcomings in that it was an observational trial meaning they observed this group of people and asked them questions over a period of time, so there could be other factors or variables that lead to the results found. This study also used 24hr dietary recall questionnaires, which are notorious for discrepancies as humans have pretty crappy memories and I don’t know about you but I struggle to remember what I ate for breakfast 2 hours ago let alone everything I put in my mouth over the last 24 hours. 

Now the other aspect that the smarter Craig’s in the back will bring up is the carbohydrate content that the lowest ‘low carb’ individuals were consuming. In the data set that Mazidi and friends used, it was worth ~39% of their total energy intake. Whereas in a traditional low carb or keto diet, carbs should be < 20% of an individual’s total energy intake. So Craig will boastfully stand up and say that since the carb intake was > 20% the cohort reviewed in this study were not consuming a low carb diet, therefore the results found were actually due to consuming carbs; if carb intake was < 20% these individuals would have received nothing but benefits.

Let’s talk about this because on the surface it seems like a valid point, even though individuals that were consuming > 39% of their energy intake from carbs were not having issues, but whatever Craig. The point that is being missed here is that the amount of carbohydrates may not matter. It may again be what the carbs are being replaced with! Take a look at this little forest plot here from Mazidi’s study. See that little guy circled in red? That study showed that a low-carb diet seemed to have a positive effect on death and death due to heart disease.

Figure from Mazidi study. A) Death from any cause; B) Death from heart disease; C) Death from cancer.

So what the eff was different in this study?! 

In 2014, Nakamura et al. looked at a cohort of individuals from Japan who indeed did consume a diet where ~20% of their energy intake was from carbs. 

Wait. Craig is right?! 

Not quite. In the study by Nakamura, participants were consuming significantly more plant-based proteins, less saturated fats, and more unsaturated fats compared to the traditional low-carb diet that is composed of more animal proteins and fats. Therefore, this data shows that it is not a matter of high or low carb diets increasing an individual’s risk, it is the amount of saturated fats being consumed that we need to be worried about. 

So, I am sorry low-carbers – the bulletproof coffee, side of bacon, and extra stick of butter should probably go if you want to reduce your risk of death and heart disease. High or low carb doesn’t seem to matter. The diet YOU can sustain for the long term is the right diet for you. If you want some extra health benefits then I would suggest probably eating more plant proteins, fish, and healthy oils like olive oil. I take this to mean I can eat more sashimi – which if I could afford would eat every single day. Hopefully, the healthy fats will counteract the mercury poisoning?

Anyways you beautiful people. That is all for today! Let me know your questions and of course, remember small tweaks lead to massive peaks! 


Until next time, 

Dr. Dan

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