Various dietary approaches such as the 16/8 method, the 5:2 diet, and the 12/12 method, have been developed to address cardiometabolic benefits and drawbacks of intermittent fasting (IF) [
66]. Various clinical trials have also explored the effects of fasting on body weight, insulin sensitivity and overall metabolic health [
66,
67,
68]. A recent human clinical trial from patients with ST-elevation myocardial infarction (STEMI) showed that IF significantly improved left ventricular ejection fraction and reduced diastolic blood pressure compared to regular diet, with improvement occurring up to 6 months after STEMI [
69]. However, to date, no randomized controlled trials in humans have specifically investigated the effects of fasting on HF progression. In contrast, animal studies suggested that alternate day fasting (ADF), a commonly used form IF in rodent models, potentiates cardiotoxic effects of doxorubicin chemotherapy, which causes HF in humans, highlighting the need for cautious exploration of IF in this context [
70]. Mechanistically, ADF increases myocardial nuclear transcription factor EB (TFEB), which drives HF progression after doxorubicin [
70]. However, other rodent studies do corroborate potential beneficial effects of IF in the cardiometabolic disease setting suggesting that the role of IF may be context dependent [
71,
72,
73]. Numerous other studies have reviewed both continuous energy restriction and intermittent energy restriction for their other effects on reducing body fat mass, promoting weight loss, and improving cardiovascular health [
74,
75,
76]. In a randomized controlled trial involving geriatric obese patients with HFpEF, caloric restriction alone led to a significant reduction in serum Interleukin-6, TNF-α-receptor-I, growth differentiation factor-15, cystatin C, and N-terminal pro-b-type natriuretic peptide) (
Table 1.), resulting in improved physical performance and exercise tolerance compared to the group that combined caloric restriction with aerobic exercise [
77]. In a separate randomized controlled trial, no significant impact on patients’ quality of life was found when they underwent caloric restriction, aerobic exercise, or a combination of both, as assessed through a questionnaire-based evaluation (
Table 1.) [
78]. On the other hand, insufficient caloric intake is known to worsen post-discharge quality of life and increase burden of readmission in HF patients [
79]. Therefore, the potential benefits of calorie restriction must be determined on a case-by-case basis [
76]. Although a sustained, 5-10% weight loss is recommended in HF patients with a BMI >35 kg/m
2, weight loss puts lower-BMI groups at greater risk of mortality, likely reflective of cachexia [
80]. Without the addition of resistance training, weight lost across all groups as a result of calorie restriction can be, in part, due to a loss of skeletal muscle mass [
81]. Thus, calorie restriction alone cannot be universally recommended as an HF treatment, but rather a strategy to mitigate one of its main risk factors: obesity [
80].