Is ketosis needed to combat inflammation?

Claim 1: “The reason why everybody is chronically inflamed is because they’re not getting into ketosis"

Fact-check: This claim is not supported by the evidence, and oversimplifies a complex and multifactorial process. Chronic inflammation is caused by different factors, and the literature identifies several established drivers besides ketosis status.

Inflammation is a normal biological response of the body to infections or injuries. However, when inflammation becomes chronically elevated, it can lead to a wide range of mental and physical health problems, such as cardiovascular disease, type 2 diabetes, depression, neurodegenerative diseases, among others (source; source). Drivers for chronic inflammation include excess visceral fat, poor sleep, poor diet, chronic infection, autoimmune processes, dysbiosis (alteration in the gut microbiome), smoking, air pollution and physical inactivity (source; source).

Ketosis is a condition where the body uses ketone bodies (derived from fat) as an alternative source of fuel, instead of glucose, which is derived from carbohydrates. The keto diet (or ketogenic diet) is a dietary pattern that is a high-fat, low-carbohydrate and moderate protein diet that induces a metabolic state of ketosis. Though there is evidence that ketosis can improve some markers associated with inflammation (source), there is currently no robust evidence  or official guidance that support the statement that lack of ketosis is associated with chronic inflammation. Other dietary patterns that have shown anti-inflammatory effects include the mediterranean style and a plant-based diet (source). 

‍

Claim 2: "Ketosis triggers some major anti-inflammatory pathways"

Fact-check: This claim is partly accurate, but overstated. 

Current evidence suggests that a keto diet can improve certain inflammation markers, and may aid in the treatment of some conditions. For instance, the keto diet has been long established  as a treatment option for  epilepsy, and its applicability for other conditions  (including metabolic and neurodegenerative conditions, like obesity and Alzheimer’s disease) has been an expanding area of research (source). 

A systematic review and meta-analysis published in 2024 found that ketogenic diets significantly lowered TNF-α and IL-6 (two pro-inflammatory molecules) compared to control diets, but showed no significant effect on other inflammation markers (including CRP, IL-8, IL-10). The reduction was larger in trials of 8 weeks or less and in participants  50 or younger (for TNF-α), and in people with obesity (for IL-6). The authors' own conclusion is that adherence to a ketogenic diet appears to improve some (not all) inflammation-related markers, but that further research is needed to better understand long-term effects, optimal duration, and exact mechanisms of how the keto diet influences  inflammation. Moreover, most of the studies included adults with overweight/obese and/or type 2 diabetes  patients rather than healthy individuals, and thus the findings cannot be generalised to the general population.

So, even though there is evidence that a ketogenic diet can lower certain inflammatory markers (TNF-α and IL-6), the effect appears to depend on who's dieting and for how long. This supports a part of the claim, but not the overall idea of the post that ketosis is "the" way to shut down inflammation.

‍

Claim 3: “We don't make vitamin C... so now we have to practice ketosis" as the "proper way" to generate anti-inflammatory molecules

Fact check: This claim is vastly overstated. Though the genetic fact is backed by evidence, the leap to ketosis as the way to generate anti-inflammatory molecules is not. 

Vitamin C has several functions in the body, including helping the body produce collagen, keep blood vessels and capillary walls firm, and healing cuts/wounds. As an antioxidant, it helps neutralise free radicals that contribute to  oxidative stress (a process closely tied to inflammation) and supports normal immune function (source). 

It is well-established in the literature that humans (alongside other animals) lost the functional gene (GULO) for making vitamin C many millions of years ago (source), and thus we rely on the food we eat to provide this vitamin. Fruits and vegetables are a major  source of vitamin C; some of these with a high content of vitamin C include citrus fruits, guava, red and green peppers, kiwi, lychee, broccoli and papaya (among others).

However, the current evidence does not support that ketosis is a "replacement" pathway that evolved, or that the body is somehow "supposed to" rely on, because of this lost vitamin C synthesis capacity. There are several hypotheses of why this function could have been lost, including that the GULO gene could have been inactivated due to an adequate vitamin C intake within the diet (source).

Moreover, recommending  the general population to follow a keto diet could be harmful. A review published by the Journal of the American Heart Association notes  that it is not uncommon to observe  cases of healthy-weight individuals with elevated LDL cholesterol after following a ketogenic diet, raising concerns about an increased  risk of developing cardiovascular disease. Another review published in 2025 notes specific cases where the keto diet should be approached with caution, including individuals  with type 1 or type 2 diabetes (particularly those taking medication), gallstones, psychosocial stress, intense physical activity, cardiac arrhythmia, who are underweight, or taking certain medications that can negatively interact with the keto diet.

Final take-away

The lack of ketosis is not currently recognised as the main explanation for chronic inflammation. The evidence points to multiple interacting causes, with stronger support for overall diet quality, adiposity, and lifestyle than for ketosis status alone. The keto diet may be used as part of  treatment for  certain conditions , but the optimal duration, long-term risks and actual mechanisms of how it can work in the body are still a matter of research. It is not recommended to follow a keto diet without the supervision  of a qualified health professional.

‍

We have contacted Candi Frazier and are awaiting a response.

Disclaimer

This fact-check is intended to provide information based on available scientific evidence. It should not be considered as medical advice. For personalised health guidance, consult with a qualified healthcare professional.