The biological starting point is a mismatch between how tumors and immune cells process fuel. Most cancers exhibit the Warburg effect, a heavy reliance on aerobic glycolysis even in the presence of oxygen, which generates abundant lactate, promotes extracellular acidosis, and drives redox imbalance. This metabolic environment contributes to T-cell exhaustion, creating what the review describes as a negative feedback loop between tumor metabolic plasticity and immune suppression. Modern therapies, whether checkpoint inhibitors or cytotoxic drugs, often fail not because they cannot reach the tumor, but because the tumor’s metabolic adaptations and the immunosuppressive microenvironment they create blunt sustained responses.

The ketogenic diet intervenes by sharply reducing circulating glucose and insulin while raising ketone bodies, principally β-hydroxybutyrate and acetoacetate. For glycolysis-dependent tumor cells, this creates metabolic stress: glycolytic flux falls, lactate production drops, and the flow of glycolytic intermediates into the pentose phosphate pathway is restricted, depleting the nucleotide and NADPH pools needed for DNA synthesis and antioxidant defense. Ketogenic feeding also downregulates key glycolytic enzymes such as pyruvate kinase M2 and has been shown to increase mitochondrial reactive oxygen species in tumors. Cells already stressed by hypoxia, oncogenic signaling, or replication stress may then be pushed closer to the threshold at which chemotherapy- or radiation-induced damage becomes lethal.

Crucially, the review emphasizes that this selectivity is relative rather than absolute. Normal tissues and immune cells possess greater metabolic flexibility and can switch from glucose to fatty acid and ketone oxidation. Tumors with low levels of ketolysis enzymes, such as succinyl-CoA:3-ketoacid CoA transferase, cannot efficiently use β-hydroxybutyrate or acetoacetate as oxidative fuels and remain dependent on glycolytic substrates. Some tumors, however, retain functional ketolytic pathways and can adapt to ketosis, which limits the metabolic selectivity hypothesis. The diet’s benefits, the authors argue, are most likely in tumors that are highly glucose-dependent yet cannot compensate through ketone oxidation, and patient selection will therefore hinge on characterizing each tumor’s metabolic phenotype.

Ketone bodies are not merely fuel. β-hydroxybutyrate acts as a signalling metabolite with two notable functions: it engages the hydroxycarboxylic acid receptor 2 to dampen NF-κB and NLRP3 inflammasome-mediated inflammation, and it functions as an endogenous inhibitor of class I histone deacetylases, opening chromatin and altering transcriptional programs toward stress resistance and, in some contexts, anti-tumor states. Acetyl-CoA generated during ketolysis can feed into the citric acid cycle and support histone acetylation in immune cells, directly linking metabolism to gene expression. Experimental work shows that activated CD8-positive T cells can oxidize ketones to boost mitochondrial membrane potential and TCA-cycle flux, and that impairing ketone oxidation enzymes compromises T-cell proliferation and anti-tumor activity.

On the immune side, the diet may address one of the central barriers to durable immunotherapy responses: T-cell exhaustion. In the glucose-starved tumor microenvironment, activated T cells normally compete with glycolytic tumor cells and lose effector function. Under ketogenic conditions, metabolically flexible cytotoxic lymphocytes can sustain themselves through oxidative phosphorylation, and experimental studies suggest reductions in exhaustion markers such as PD-1, TIM-3, and LAG-3 in some settings. The diet may also re-polarize tumor-associated macrophages from immunosuppressive M2-like toward inflammatory M1-like phenotypes, and by lowering lactate and acidosis it may relieve metabolic suppression of dendritic cell antigen presentation. Effects on regulatory T cells are less predictable, since Treg maintenance depends on fatty acid oxidation and local nutrient composition, so ketosis may shift the nutrient competition between Tregs and effector CD8-positive cells rather than uniformly favoring one population.

These immunometabolic effects provide a mechanistic rationale for combining the diet with checkpoint inhibitors and adoptive cell therapies. Preclinical models have shown that ketogenic interventions can improve responses to PD-1 blockade, potentially converting immunologically cold tumors into more therapy-responsive states. For CAR-T therapy in solid tumors, where hypoxia, nutrient deprivation, and chronic antigen stimulation undermine engineered T-cell survival, ketogenic states could enhance oxidative metabolism and mitochondrial robustness, promoting memory-like T-cell states that sustain long-term responses. The review also explores synergy with targeted agents: reduced insulin and IGF-1 signaling may complement PI3K/Akt/mTOR inhibitors, and combinations with metformin or IDH inhibitors are biologically plausible, though evidence for clinically meaningful benefit remains preliminary.

A third layer of the framework involves the gut microbiome. By altering nutrient availability, the ketogenic diet changes microbial community composition and metabolite production, including short-chain fatty acids such as butyrate and propionate, which support epithelial barrier integrity, promote T-cell differentiation, and inhibit histone deacetylases. Certain bacterial taxa are associated with improved T-cell activation and better outcomes during anti-PD-1 therapy, raising the possibility that diet-induced microbiome remodeling could influence immunotherapy response. The authors stress, however, that direct proof linking ketogenic microbiome changes to improved cancer treatment outcomes remains preclinical, and connections between specific microbial shifts and therapy response have not been established as causal.

The clinical evidence base lags well behind the mechanistic story. Human studies to date, largely small prospective trials, pilot studies, and retrospective observations in glioblastoma, breast cancer, and gastrointestinal tumors, have consistently demonstrated that the diet reliably changes systemic metabolism, lowering glucose and insulin signaling and raising blood ketones when nutritional ketosis is achieved. Evidence for anti-tumor efficacy, however, is inconsistent, with some reports of disease stabilization and others showing no tumor control benefit. Adherence is a major obstacle, particularly in patients experiencing anorexia, nausea, or weight loss, and nutritional ketosis itself is a non-uniform exposure, with patients on ostensibly identical diets achieving different β-hydroxybutyrate levels. The review calls for future trials to report objective measures of ketosis, dietary composition, caloric and protein intake, and predefined metabolic targets, and to develop biomarker-guided approaches that identify which tumors are metabolically vulnerable.

The overarching message is one of calibrated optimism. The ketogenic diet should not be viewed as inherently anti-carcinogenic, nor as a substitute for established cancer therapies; current evidence does not support its use as an independent curative treatment. Instead, its greatest promise may lie in creating a coordinated biological environment, low glucose and insulin, elevated ketone signalling, preserved T-cell mitochondrial fitness, reduced dysfunctional inflammation, remodeled microbiome metabolites, and altered chromatin states, in which susceptible tumors become more sensitive to the therapies already in clinical use. Until large, controlled prospective trials clarify optimal patient selection, protocols, and long-term safety, the authors conclude, ketogenic strategies should remain carefully supervised adjunctive approaches within an emerging field of precision metabolic oncology.

Subject of Research: Ketogenic diet as an immunometabolic sensitization strategy in cancer therapy

Article Title: Ketogenic diet as a systems-level immunometabolic sensitization strategy in cancer therapy: integrating metabolism, immune reprogramming, microbiome dynamics, and epigenetic regulation

Article References: Mannan, M. S., Khan, M. W., Haseeb Khan, M. A., Javed, A., Hussain, S. M., & Adil, H. (2026). Ketogenic diet as a systems-level immunometabolic sensitization strategy in cancer therapy: integrating metabolism, immune reprogramming, microbiome dynamics, and epigenetic regulation. Medical Oncology, 43(11), Article 297. https://doi.org/10.1007/s12032-026-03425-0

Image Credits: AI Generated

DOI: 10.1007/s12032-026-03425-0

Keywords: ketogenic diet, cancer metabolism, immunotherapy, beta-hydroxybutyrate, tumor microenvironment, gut microbiome, epigenetic regulation, T-cell exhaustion, Warburg effect, checkpoint inhibitors, nutritional ketosis, precision oncology