. 2023 Jun 27;82(5):664–675. doi: 10.1093/nutrit/nuad081

Table 1.

Effect of prolonged fasting on body weight and cardiometabolic risk markers

Reference	Subjects	Fast duration, d	Design and intervention groups	Body weight	Body composition			BP	Plasma lipids			Glucoregulatory factors				Ketones	Adverse events
Reference	Subjects	Fast duration, d	Design and intervention groups	Body weight	FM	FFM	WC	BP	LDL	HDL	TG	FBG	Fasting insulin	IR	A1c	Ketones	Adverse events
Wilhelmi de Toledo, 2018²³	n = 656; M, F; age: 54 ± 1 y; overweight; no diabetes	5	Nonrandomized trial; inpatient clinic; Buchinger fast; ∼250 kcal/d intake	↓4.0%^*	—	—	↓^*	↓S^, ↓D^	↓^*	↓^*	↓^*	↓^*	—	—	↓^*	↑^* AA (Urine)	↑ Insomnia ↑ Fatigue ↑ Dry mouth ↑ Hunger ↑ Headache
Jiang, 2021¹⁸	n = 45; M, F; age: ND; normal weight; no diabetes	5	Nonrandomized trial; outpatient; water-only fast	↓6.4%^*	—	—	↓^*	↓S^, ↓D^	↑^*	↓^*	↑^*	—	↓^*	—	—	↑^* AA (Urine)	↑ Hunger ∅ Liver function ∅ Electrolytes ∅ Renal function ↓ T3, TSH
Berger, 2021¹⁶	n = 20; M, F; age: 56 ± 6 y; overweight; T1DM	7	Nonrandomized trial; inpatient clinic; Buchinger fast; ∼250 kcal/d intake	↓2.1%^*	—	—	—	∅ S, ∅ D	∅	↓^*	—	∅	—	—	∅	↑^* BHB (Blood)	No acidosis ↑ Insomnia ↑ Fatigue ↑ Dry mouth
Li, 2013¹⁹	n = 30; F; age: 50 ± 8 y; obese; no diabetes	7	Nonrandomized trial; outpatient; Buchinger fast; ∼250 kcal/d intake	↓6.7%^*	—	—	—	↓S^, ↓D^	↓^*	↓^*	∅	—	↓^*	—	—	—	—
Li, 2017²⁰	n = 32; M, F ; age: 65 ± 2 y ; obese; T2DM	7	RCT; outpatient; (1) Buchinger fast, ∼250 kcal/d intake; (2) Control—Med diet	(1) ↓3.9%^^,^; (2) ↓2.1%^	—	—	(1) ↓^^,^*; (2) ∅	(1) ↓S, ↓D; (2) ∅	(1) ∅; (2) ∅	(1) ∅; (2) ∅	(1) ∅; (2)∅	(1) ∅; (2) ↓^*	(1) ∅; (2) ↓^*	(1) ∅; (2)∅	(1) ∅; (2) ∅	—	↑ Dizziness ↑ Headache
Ogłodek, 2021²¹	n = 12; M; age: 50 ± 2 y; normal weight; no diabetes	8	Nonrandomized trial; outpatient; water-only fast	↓7.4%^*	BIA↓^*	BIA↓^*	—	—	—	—	—	—	—	—	—	↑^* BHB (Blood)	∅Renal function ↓ Plasma Na
Dai, 2022¹⁷	n = 13; M; age: 39 ± 3 y; overweight; no diabetes	10	Nonrandomized trial; inpatient clinic; water-only fast	↓9.8%^*	DXA↓^*	DXA↓^*	↓^*	↓S^*, ∅D	↑^*	∅	∅	∅	↓^*	↓^*	↓^*	↑^* BHB (Blood)	∅Renal function ↓ Plasma Na ↓ Plasma Cl ∅ Liver function
Wilhelmi de Toledo, 2018²³	n = 530; M, F; age: 56 ± 1 y; overweight; no diabetes	10	Nonrandomized trial; inpatient clinic; Buchinger fast; ∼250 kcal/d intake	↓5.3%^*	—	—	↓^*	↓S^, ↓D^	↓^*	↓^*	↓^*	↓^*	—	—	↓^*	↑^* AA (Urine)	↑ Insomnia ↑ Fatigue ↑ Dry mouth ↑ Hunger ↑ Headache
Wilhelmi de Toledo, 2018²³	n = 196; M, F; age: 54 ± 1 y; overweight; no diabetes	15	Nonrandomized trial; inpatient clinic; Buchinger fast; ∼250 kcal/d intake	↓7.0%^*	—	—	↓^*	↓S^, ↓D^	↓^*	↓^*	↓^*	↓^*	—	—	↓^*	↑^* AA (Urine)	↑ Insomnia ↑ Fatigue ↑ Dry mouth ↑ Hunger ↑ Headache
Scharf, 2022²²	n = 54; M, F; age: 57 ± 3 y; obese; no diabetes	17	Nonrandomized trial; inpatient clinic; water-only fast	↓10.2%^*	—	—	↓^*	↓S^, ↓D^	↓^*	∅	↑^*	↓^*	↓^*	↓^*	—	—	—
Wilhelmi de Toledo, 2018²³	n = 37; M, F; age: 54 ± 2 y; obese; no diabetes	20	Nonrandomized trial; inpatient clinic; Buchinger fast; ∼250 kcal/d intake	↓7.3%^*	—	—	↓^*	↓S^, ↓D^	↓^*	↓^*	↓^*	↓^*	—	—	↓^*	↑^* AA (Urine)	↑ Insomnia ↑ Fatigue ↑ Dry mouth ↑ Hunger ↑ Headache

P < .05, significantly different from baseline (within-group effect).

^**

P < .05, significantly different from the control group (between-group effect).

Abbreviations: A1c, glycated hemoglobin; AA, acetoacetic acid; BHB, beta-hydroxybutyrate; BIA, bioelectrical impedance analysis; BP, blood pressure; D, diastolic blood pressure; DXA, dual-energy X-ray absorptiometry; F, female; FBG, fasting blood glucose; FFM, fat-free mass; FM, fat mass; HDL, high-density lipoprotein cholesterol; IR, insulin resistance; LDL, low-density lipoprotein cholesterol; M, male; Med diet, Mediterranean diet; ND, not disclosed; RCT, randomized controlled trial; S, systolic blood pressure; T1DM, type 1 diabetes mellitus; T2DM, type 2 diabetes mellitus; T3, triiodothyronine; TG, triglycerides; TSH, thyroid-stimulating hormone; WC, waist circumference; –, not measured; ∅, no statistically significant change.