Intermittent fasting for cardiovascular disease risk factor reduction: A narrative review of current evidence

Background The metabolic syndrome (MetSy), which is defined by the spectrum of obesity, insulin resistance and dyslipidaemia, is recognised as a major contributor to the overall risk of developing cardiovascular disease. Intermittent fasting (IF), which encompasses dieting plans with varying schedules of fasting, may be an effective method of reducing the burden of MetSy and the consequent cardiovascular events in the face of a worsening obesity epidemic in the contemporary society. Aims Despite the widespread public interest there is a serious lack of scientific understanding of the evidence base and the safe, optimal recommendations. This has created a level of public confusion that we endeavour to address by this narrative review of the published literature. Methods This narrative literature review summarises the current findings and suggests which regimens may be more effective and where future research in this area should be focused. Results Although the ideal regimen for IF remains unclear, there is promising evidence that alternate day fasting or modified fasting regimens, paired with or without continuous caloric restriction, may be more effective than continuous caloric restriction alone. Conclusion IF has been shown in the small number of human clinical trials discussed here to be an alternative to continuous caloric restriction in reducing the factors that contribute to the development of cardiovascular disease. Long-term randomised, controlled trials comparing continual caloric restriction and IF are required to objectively assess energy intake, energy expenditure, adherence, disease outcomes and metabolic factors.