Plants are good for you, so why do wellness influencers call them toxic?
In an Instagram reel shared recently through Billy Carson’s account ‘4biddenknowledge’, Dave Asprey suggested that foods such as spinach, kale, almonds, raspberries, and beets are not “good for you” because they are “high oxalate foods,” which he claims exceed what the body can handle.
This fact check examines whether scientific evidence supports the claim that oxalate-rich foods should be avoided.
Oxalates are naturally occurring compounds that, in most cases, are excreted without harm. Kidney stone risk can be managed through proper hydration and calcium intake, and there is no credible evidence linking oxalate consumption to brain lesions, ageing, or widespread toxicity. The benefits of a diet rich in plant foods are well-documented, contradicting the claim that “most plants are not good for you.”
Misinformation about nutrition can cause unnecessary fear and lead people to restrict foods that are actually beneficial. Claims like these, which oversimplify complex health topics, often spread through storytelling rather than science. Understanding how oxalates function in the body helps prevent unnecessary dietary restrictions and ensures people make informed, balanced nutritional choices.
Beware of oversimplified health claims that focus on single food components while ignoring overall dietary context.
Beyond evaluating the claim itself, this fact-check will consider how the argument that “most plants are not good for you” is presented. Misinformation often extends beyond isolated factual inaccuracies; it is shaped by the broader narratives that tie those claims together.
In this case, Dave Asprey does not cite any scientific studies to support his argument that oxalates make most plants unhealthy. Instead, he presents the idea through storytelling, a method that can be compelling but should always be weighed against scientific evidence.
What are oxalates, and where does the claim that oxalate-containing foods should be avoided come from?
The idea that oxalate-rich foods should be avoided was popularised by Sally K. Norton in her book Toxic Superfoods, where she argues that oxalates contribute to a range of health problems. The most commonly shared concern is the risk of developing kidney stones, which Dave Asprey also mentions in this post.
Oxalates are naturally occurring compounds found in many plant foods, including leafy greens, beans, and nuts. They can bind to calcium in the digestive tract, forming calcium oxalate, a major component of kidney stones. Contrary to Dave Asprey’s claim that many plant foods contain oxalates “far in excess of what your body can handle,” in most people, oxalates are safely excreted through urine and stool without causing issues.
Since kidney stones often contain calcium oxalate, it might seem intuitive that avoiding oxalate-rich foods could prevent stone formation. However, research suggests that dietary oxalate is one factor in stone development, and context matters when assessing risk.
For example:
- Calcium intake is important: When consumed together, dietary calcium binds to oxalates in the gut, preventing absorption into the bloodstream. Dr. David Goldfarb recommends consuming dairy or other calcium sources alongside oxalate-containing foods rather than eliminating them.
- Hydration plays a key role: Drinking enough fluids helps dilute oxalates in the urine, reducing the likelihood of kidney stone formation.
- Overall diet matters more than individual compounds: This meta-analysis shows that overall vegetable intake and total fibre intake were consistently linked to a reduced risk of kidney stones. Beyond concerns related to kidney stones, numerous studies indicate that plant-based diets are associated with a lower risk of chronic disease, contradicting the idea that oxalates should be avoided entirely due to inherent harm.
Dave Asprey’s statements don't take into account the fact that plant-based diets can be recommended to reduce the risk of kidney stones. For example, in this review of the available evidence on the role of diet in kidney stone prevention, researchers concluded that “a balanced vegetarian diet with dairy products seems to be the most protective diet for kidney stone patients.”
The argument that oxalate-rich foods should be avoided because of kidney stones is reductive in the sense that it appeals to the cherry-picking fallacy, where only the information which supports the author’s narrative or diet is selected, while contradictory evidence is left out.
For a deeper exploration of the claim that oxalate-containing foods should be avoided because of their association with kidney stones, you can read our full fact-check here.
Oxalates and Brain Health
Dave Asprey also says that oxalates are a common cause of many other health issues, including IBD, PCOS, brain fog, and even brain lesions. “This is oxalate forming through the body, it calcifies you, makes you old, causes brain lesions.”
We have reached out to experts in brain health to discuss this alleged association between oxalates and accelerated ageing:
As board-certified neurologists committed to evidence-based practice, we find these claims both inaccurate and misleading.
Dietary oxalates are naturally present in many fruits and vegetables. In the vast majority of individuals, the body processes and excretes these compounds efficiently. While individuals with specific medical conditions—such as certain kidney disorders—may need to moderate their oxalate intake, there is no credible scientific evidence to suggest that normal consumption of vegetables causes widespread “calcification,” brain lesions, or accelerated aging.
There is no legitimate research linking typical vegetable consumption to brain lesions or significant “brain fog.” Conversely, diets high in antioxidants, vitamins, and minerals—abundant in plant-based foods—are consistently associated with better cognitive function over the lifespan.
Debunking the Narrative That Plants Are Designed to Harm You
Some proponents of low-oxalate diets claim that plants are inherently harmful because they contain ‘natural defence compounds.’ Dave Asprey reinforces this idea by stating:
“Go into the forest, pick something and eat it, and you’ll probably end up in the hospital. Most plants wanna kill you.”
Dr Gil Carvalho, who directs and hosts Nutrition Made Simple!, an evidence-based educational platform designed to help the public navigate nutrition information, puts it like this:
“The question is always the same: do we have evidence that that thing actually causes disease in the natural context? Not purified a thousand times, not in mice, etc.”
While it’s true that some wild plants and mushrooms are toxic, this doesn’t apply to the plant foods people actually eat, like spinach, kale, or almonds. The presence of naturally occurring compounds in these plants does not make them harmful.
The Problem With Reducing Foods to Single Components
A key issue with Asprey’s claim is that it isolates oxalates without considering everything else that plants contain . As Dr. Gil Carvalho explains:
“It's trying to boil down a food to a few of its components, divorced from actual observable health effects in the medium and long term—which is what we all care about.”
Focusing solely on oxalates overlooks the abundance of beneficial nutrients such as fibre, vitamins, and polyphenols found in plant foods, and the protective role plant compounds play in reducing your risk of several diseases.
Social media nutrition claims often go viral when they are sensationalised or overly simplistic. However, mainstream dietary guidelines rarely advocate for the outright elimination of entire food groups. Instead, they promote balance and variety, recognising that nutritional needs vary between individuals. Isolating one compound, such as oxalate, leads to misleading conclusions.
Dave Asprey’s argument focuses on oxalates but ignores extensive research showing the benefits of plant-rich diets. For example, the following studies indicate that increasing plant consumption is linked to:
- Reduced cardiovascular disease risk—a meta-analysis found that vegetarian diets were associated with a 25% lower risk of ischemic heart disease and an 8% lower risk of total cancer incidence.
- Improved longevity—finally, this systematic review found a protective effect of plant-based diets against chronic disease mortality.
An extensive body of peer-reviewed research demonstrates that diets rich in vegetables (yes, those containing oxalates!) are associated with better cardiovascular health, improved metabolic markers, and reduced risk of various chronic diseases, including several forms of cancer. The claim that “most plants aren’t good for you” is diametrically opposed to established nutritional science and long-standing public health guidelines.
While it can be enticing to pin a long list of ailments on a single dietary component, oversimplifications often lead to unnecessary fear-mongering. Vegetables (and other plants) are integral to a balanced, health-promoting diet. Claims that demonize them due to oxalates neglect both the complexity of human physiology and the weight of high-quality scientific evidence.
Conclusion: How Misinformation Can Harm Your Health
The fear-mongering around oxalates is an example of how nutrition misinformation can spread through compelling storytelling rather than evidence-based science. While oxalates can contribute to kidney stones in certain individuals, they are not responsible for the wide array of health conditions claimed by some influencers.
Instead of avoiding oxalate-rich foods entirely, an evidence-based approach to nutrition involves:
✔ Adequate hydration to prevent kidney stone formation.
✔ Consuming sufficient calcium to bind oxalates in the gut.
✔ Maintaining a balanced and diverse diet to ensure overall health.
We appreciate the enthusiasm of individuals who wish to optimize health; however, we recommend approaching novel or dramatic health claims with skepticism and consulting qualified healthcare providers—or at the very least, published, peer-reviewed research—before making drastic dietary changes.
And in case anyone still wonders about vegetables and brain health, the “miracle cure” for misinformation remains the same as ever: a generous serving of actual evidence.
📚 Sources
Carvalho, Gil. Nutrition Made Simple! https://www.youtube.com/@NutritionMadeSimple
Oxalates and Kidney Stones: https://www.youtube.com/watch?v=qq1nkGqo69E
Scientist Reacts to Carnivore Doctor on Joe Rogan: https://www.youtube.com/watch?v=cjL8wv2CXM4
Jafari, S. et al. (2022). “Plant-based diets and risk of disease mortality: a systematic review and meta-analysis of cohort studies.” https://pubmed.ncbi.nlm.nih.gov/33951994/
Ferraro, P.M. et al. (2020). “Risk of Kidney Stones: Influence of Dietary Factors, Dietary Patterns, and Vegetarian–Vegan Diets.” https://pmc.ncbi.nlm.nih.gov/articles/PMC7146511/#sec5-nutrients-12-00779
Bing-Biao, L. et al. (2020). Dietary and lifestyle factors for primary prevention of nephrolithiasis: a systematic review and meta-analysis. https://bmcnephrol.biomedcentral.com/articles/10.1186/s12882-020-01925-3
Sadler, I. (2024). “Plants are toxic!” Are oxalates destroying your health?” https://www.foodfacts.org/articles/are-oxalates-destroying-your-health
Dinu, M. et al. (2017). “Vegetarian, vegan diets and multiple health outcomes: A systematic review with meta-analysis of observational studies.” https://pubmed.ncbi.nlm.nih.gov/26853923/#:~:text=Conclusions:%20This%20comprehensive%20meta%2Danalysis,of%20incidence%20from%20total%20cancer.
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