Ketogenic and Low-Carbohydrate Diets in Prostate Cancer: Metabolic Rationale, Preclinical Evidence, and Preliminary Clinical Data

Background: Prostate cancer (PCa) is the most commonly diagnosed malignancy in men and a leading cause of cancer-related mortality worldwide. Growing evidence indicates that metabolic syndrome components, including obesity, insulin resistance, and hyperglycemia, contribute to PCa development, and progression to more aggressive form. At the same time, standard treatments such as androgen deprivation therapy (ADT) and androgen receptor pathway inhibitors (ARPIs) significantly improve oncologic outcomes but are associated with adverse metabolic effects, including increased fat mass, insulin resistance, and sarcopenia, potentially worsening patients’ overall metabolic profile and quality of life. Tumor progression in PCa is strongly driven by androgen receptor (AR) signaling, which is closely linked to cellular metabolic reprogramming, highlighting metabolism as a potential therapeutic target. Aim: The aim of this study was to evaluate and synthesize current evidence on the role of the ketogenic diet (KD) in PCa, with particular emphasis on its interaction with hormonal therapies, underlying metabolic and endocrine mechanisms, and its potential application as an adjunctive strategy in integrated oncologic care. Results: The KD, characterized by high fat and very low carbohydrate intake, induces a metabolic state of ketosis that reduces circulating glucose, insulin, and insulin-like growth factor 1 (IGF-1), potentially counteracting metabolic alterations associated with PCa and its treatments. Preclinical studies consistently demonstrate that carbohydrate restriction and KD can slow tumor growth, modulate key oncogenic pathways such as PI3K/AKT/mTOR, reduce systemic insulin signaling, and enhance survival in prostate cancer models. Additionally, emerging evidence suggests possible synergistic effects when KD is combined with standard therapies, including ADT and immunotherapy. Clinical data, although limited, indicate that low-carbohydrate dietary interventions may improve metabolic parameters and could delay biochemical progression, as suggested by increased prostate-specific antigen (PSA) doubling time. However, results across studies remain heterogeneous, and robust evidence on long-term oncologic outcomes is lacking. Conclusions: Overall, the KD represents a promising but still experimental strategy in PCa management, requiring careful nutritional supervision to avoid adverse effects such as unintended weight loss or sarcopenia. Further well-designed randomized clinical trials are needed to clarify its safety, efficacy, and role in routine clinical practice.