Intermittent Fasting in Chronic Heart Failure: A Systematic Review of Safety and Physiological Outcomes

Interest in intermittent fasting regimens has expanded substantially due to its reported metabolic effects. However, whether such dietary patterns are safe for individuals living with chronic heart failure remains unclear. This issue is particularly relevant for patients who fast for religious observance, including Ramadan. We therefore performed a systematic review to evaluate the clinical safety and physiological implications of intermittent fasting regimens in stable heart failure populations.

The review protocol adhered to established reporting standards for systematic reviews. Multiple electronic databases were systematically searched from inception through December 2025 to identify studies evaluating intermittent fasting regimens in adults with chronic heart failure. Both randomized and observational designs were considered eligible. Key outcomes included clinical deterioration, cardiovascular events, New York Heart Association functional status, left ventricular systolic performance, and natriuretic peptide levels. Where data allowed, pooled analyses were conducted; otherwise, findings were summarized narratively.

Five observational studies fulfilled inclusion criteria, three of which provided comparable data for quantitative synthesis, comprising 1345 participants. Across studies, fasting was not associated with increased rates of heart failure decompensation, major cardiovascular events, or mortality relative to non-fasting periods. Functional status remained generally stable, with a tendency toward improved symptom classification among fasting participants. Measures of systolic function and natriuretic peptides showed no clinically meaningful worsening.

In clinically stable individuals with chronic heart failure, intermittent fasting regimens, including Ramadan fasting, were not linked to short-term adverse clinical outcomes based on currently available observational evidence.