Keto and the Carnivore Diets: What We Know…

black and white thinking carnivore cognitive distortions confirmation bias keto Feb 03, 2025
Keto and Carnivore

There aren’t any high-quality, long-term studies on the carnivore diet, which is a big red flag when assessing its safety and effectiveness. What we do know is that cutting out all plant-based foods can lead to nutrient deficiencies—especially fiber, vitamin C, and beneficial phytochemicals. High intake of red and processed meat has also been linked to an increased risk of heart disease and certain cancers. Plus, without fiber, digestive issues like constipation become a real concern.

 

“But what about the people who say they’ve never felt better?”

 

While some people claim to thrive on an all-meat diet, the reality is that we don’t have solid research to back up its long-term effects. Given the potential risks, it’s hard to justify following such an extreme approach when balanced diets (that include a variety of foods) have been consistently linked to better long-term health. Until better evidence emerges, the carnivore diet remains a risky, highly restrictive experiment rather than a proven strategy for lasting health.

 

Some have claimed the carnivore diet cured their autoimmune issues, boosted energy, or helped them lose weight, and yes, some people might feel better on the carnivore than they did previously, but is it because they eliminated the *overconsumption of highly processed food? Because they’re eating more protein? Because of gut microbiome changes? We don’t know. Until we have long-term data, anecdotal success stories don’t prove that the carnivore diet is safe or sustainable for most people, especially given what we know about the psychological minefield of dietary restriction from decades of reliable research. 

 

But what about keto?

 

The keto diet is well-studied for short-term benefits like weight loss and blood sugar control, but long-term research is murkier. Some studies suggest potential risks, including fatty liver, kidney stones, nutrient deficiencies, and even negative effects on cholesterol levels. Short-term side effects like nausea, fatigue, and constipation are common, while long-term concerns include bone mineral loss and increased cardiovascular risk for some people.

 

The biggest issue? Sustainability. Most people struggle to stick with keto long-term, and when they go back to normal eating, weight often returns, along with increased food obsession, anxiety, feelings of low self worth that come with feeling like we’ve failed again, and disordered eating behaviours. 

 

The real trap of diets like keto and carnivore...

 

Diets like keto and carnivore can fuel cognitive distortions—mental traps that make us see food in extremes. One of the biggest ones cognitive distortions diets like keto and carnivore encourage is black-and-white thinking—the idea that carbs are “bad” and cutting them out completely is the only way to be healthy. This all-or-nothing mindset makes people terrified of even small amounts of carbs, turning food into a battle rather than something to be enjoyed.

 

Black-and-white thinking is dangerous because of its appeal; the illusion of making life simple. Instead of dealing with nuance, B&W thinking gives clear-cut rules—good vs. bad, right vs. wrong, etc. It’s much easier to believe “carbs are bad” than to stay tuned in and present while making mindful decisions and cultivating a windsor of tolerance for uncertainty. Though the real tragedy of black-and-white thinking is that oversimplifying usually leads to worse decisions, and in turn worse outcomes in the long-term. 

 

Then there’s confirmation bias—only paying attention to success stories and ignoring research that highlights risks. People on these diets often dismiss studies showing long-term issues like high cholesterol, nutrient deficiencies, or poor sustainability.

 

Catastrophizing is another big one. Some keto and carnivore followers genuinely believe that eating a bowl of rice will immediately lead to weight gain, inflammation, or disease. Spoiler: it won’t.

 

Finally, there’s emotional reasoning—if someone feels great on keto or carnivore, they assume it’s the best diet for everyone, ignoring the fact that long-term success isn’t just about short-term energy boosts. These distortions make it harder for people to be objective about their diet and adapt when necessary, which is why so many struggle to maintain these restrictive approaches long-term.

 

In short; based on the statistics, betting your last $100 on sustained positive health outcomes or weight loss from the keto or carnivore diet would be a dicey move at best. 

 

Marcus Kain - Nutrition Coach, Strong Not Starving Founder

 

*overconsumption in this context refers to the quantity of a particular food required to produce negative health outcomes. This can differ from person to person, and hinges on multiple variables including but not limited to the inclusion of sufficient fibre, protein, and other essential nutrients, stress levels, and total caloric expenditure. 

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