Table 1.

Defining lifestyle interventions and pharmaceutical agents.

Intervention		Definition
Continuous calorie restriction		A chronic state in which caloric intake is less than caloric need by reducing daily energy intake by a minimum of 10-20%.
Intermittent fasting approaches	Intermittent energy restriction	Restricting energy intake to ~60–75% below energy requirements for short periods, followed by periods with normal energy intake (e.g., the 5:2 diet [consisting of ~5 days of eucaloric feeding and ~2 days of a very-low-calorie diet per week]).
	Short-term fasting	Temporarily fasting, typically for a period between 24 and 48 h.
	Fasting-mimicking diet	Maintaining a fasting-like state by periodically consuming a very-low-calorie, low-protein diet (not necessarily fasting).
	Time-restricted feeding	Reducing food intake to a set number of hours each day (e.g., eating in a <10 h daily period).
Ketogenic diet		An ultra-low carbohydrate diet (typically ~5% of kcal) that does not directly restrict calories or require periods of fasting. Successful generation of ketone bodies can suppress appetite and reduce plasma glucose concentrations in cancer-free individuals.
Caloric restriction mimetics (e.g., Hydroxycitrate, Resveratrol)		Compounds that mimic the beneficial effects of caloric restriction.
Anti-hyperglycemic agents (e.g., Metformin)		Agents that lower glucose levels in the blood and are often used to treat type 2 diabetes mellitus.