Table 1.

Classification of nutritional interventions

Class	Subclass/example	Definition	Reference
Fasting regimens	Caloric restriction	Reduction in daily caloric intake without malnutrition	(24)
	Total	Total absence of caloric intake for one to several days	(24)
	Intermittent	Alternance of fasting day(s) with unrestricted feeding day(s)	(26, 27)
	Time-restricted feeding	Concentration of the everyday caloric intake within a short time window, intending to create a daily period of fasting (usually over 16 hours)	(28)
Global	Mediterranean	Eating pattern based on traditional Mediterranean food intake, with a predominant share of vegetables, fruit, nuts, whole grains, and plant- or fish-based unsaturated fat	(196)
	Vegetarian	Eating pattern based on plants and excludes meat. Variations can include or exclude different animal products (dairy products, eggs)	(197)
	Vegan	Eating pattern based exclusively on plant-based food	(197)
	Paleolithic	Evolutionarily justified diet, adapted from the food available in the Paleolithic age. It is mostly comprised of vegetables, nuts, whole grains, and seeds, with a reduced portion of meat	(198)
	DASH diet	Regimen defined in the “Dietary Approaches to Stop Hypertension” (DASH) clinical trial. It demonstrated a positive impact on hypertension and served as basis for further nutrition studies	(199)
Interventions on macronutrients	Low-carb	Reduction of carbohydrates consumption, typically under 25% of the global caloric intake	(200)
	Carb-free/ketogenic	Food plan strictly restricting carbohydrates, with increased fat and appropriate protein content. It is often defined by a fat:(protein + carbohydrates) ratio of 3:1 or 4:1	(81)
	Low-fat	Reduction of fat consumption, typically under 30% of the global caloric intake	(201)
Depletion of micronutrients	Methionine	Reduction of methionine, an amino acid critical for DNA and histone methylation as well as for the one-carbon metabolism, by lowering its dietary intake or by oral methioninase administration	(63, 64)
Supplementation of micronutrients	Vitamins	Organic compounds essential for health that cannot be synthesized (or not in sufficient amounts) by the organism, and thus must be provided by food	(94)
	Spermidine	One of the two natural polyamines, a class of small, positively charged molecules with polyvalent cellular functions and global antiaging effect. Spermidine can be synthesized by the organism and assimilated through food	(146)
	Oligo-elements	Mineral compounds essential for health in small quantities, and which excessive supply of can have detrimental effects	(94)
	Polyphenols	Organic compounds naturally present in plant-based food that contain at least one aromatic ring and one hydroxyl group	(151, 152)
	Omega-3 fatty acids	Polyunsaturated fatty acids with a double bound 3 carbons away from the terminal methyl group, distributed mostly among plant-based oils and fish-based food	(153)
Microbiota-centered interventions	Prebiotics	Compound that cannot be digested by human enzymes nor absorbed by the intestine, and that will serve as a substrate for the beneficial growth or activity of the intestinal microbiota	(3, 202)
	Probiotics	Orally-administered live microorganisms intended to colonize the intestinal microbiota	(3, 202)
	Synbiotics	Oral formulation containing complementary pre- and probiotics	(3, 202)
	Postbiotics	Metabolic products released by the microbiota that have direct or indirect beneficial effects on their host	(3, 202)