Table 2.

Summary of studies assessing the effects of cocoa/dark chocolate on obesity in adults.

Study (Country)	Study Design	Participants	Dose/Form of Cocoa	Duration	Outcome Measures
Davison et al. [26] (Australia)	Randomized double-blind parallel placebo-controlled trial	N = 49; (age 18–65) (17 males, 32 females)	G1: High flavanol (902 mg) + 45 min exercise 3 times a week G2: Low flavanol (36 mg) + 45 min exercise 3 times a week G3: High flavanol (902 mg) G4: Low flavanol (36 mg) Form of cocoa: dairy-based powder mix	12 weeks	High flavanol increased FMD acutely and chronically ↓ Insulin resistance by 0.31%, diastolic BP by 1.6 mmHg in high flavanol group independent of exercise No significant effects on BMI, waist circumference, total body fat for all groups
Monagas et al. [20] (Spain)	Randomized cross-over controlled trial	N = 42 at high risk for CVD (age > 55) (19 men, 23 women)	G1: 40 g cocoa powder (495 mg polyphenols) + 500 mL skim milk/day G2: 500 mL skim milk/day	4 weeks	↑ BW in G1 No changes in SBP, DBP, heart rate in both groups; no changes in FBG, TC, TG, LDL ↑ HDL in G1 ↓ Inflammatory markers ICAM-1 in G1 No changes in IL-6, HsCRP in both groups
Almoosawi et al. [25] (UK)	Randomized cross-over controlled trial	N = 14 (age 21–50) (8 males, 6 females)	G1:20 g dark chocolate (500 mg polyphenols) G2: 20 g dark chocolate (1000 mg polyphenols)	2 weeks 1 week run-in phase, 1 week washout	No changes in BMI, WC in both groups ↓ FBG, SBP, DBP in both groups; no significant difference between groups No changes in BW, BMI, WC in both groups No changes in TC in both groups
Njike et al. [38] (USA)	Randomized controlled double-blind cross-over trial	N = 44	G1: sugar-free cocoa beverage (22 g cocoa, 805 mg flavanol) G2: sweetened cocoa beverage (22 g cocoa, 805 mg flavanol) G3: placebo beverage	6 weeks 4 weeks washout	FMD ↑ in G1, G2 compared to placebo No changes in BW, BMI, BP No changes in TG, LDL-c, HDL-c No changes in FBG, CRP, LDL oxidation
Khan et al. [19] (Spain)	Randomized controlled cross-over trial	N = 42 at high risk of CVD (age > 55) (19 men, 23 women)	G1: 40 g cocoa powder (495 polyphenols) + 500 mL skim milk G2: 500 mL skim milk	4 weeks	↑ HDL-c, ↓ oxLDL in G1 No changes of TC, TG, LDL-c ↑ Body weight in both groups No changes in BP, heart rate
Stote et al. [22] (USA)	Randomized placebo-controlled cross-over trial	N = 20 obese at risk of insulin resistance (age 25–55) (10 women, 10 men)	G1: control, 56 g cocoa powder beverage (30 mg flavanol) G2: low, 56 g cocoa powder beverage (180 mg flavanol) G3: medium, 56 g cocoa powder beverage (400 mg flavanol) G4: high, 56 g cocoa powder beverage (900 mg flavanol) G5: tea (900 mg)	5 days intervention 10 days washout	No changes in glucose, insulin, total AUC for glucose, HOMA-IR, ISI, QUICKI Total 8-isoprostane, CRP, IL-6 ↓in all cocoa treatments; with increased dose, all parameters decreased
Almoosawi et al. [24] (UK)	Randomized controlled single-blind cross-over trial	N = 42 (21 normal BMI, 21 owt/obese)	G1: 20 g dark choc (500 mg polyphenols) G2: 20 g placebo dark choc	4 weeks 2 weeks washout period	↓ SBP, DBP No changes in fasting insulin No changes in lipid profile No changes in body weight, BMI No changes in WC, WHR
West et al. [23] (USA)	Randomized placebo-controlled cross-over trial	N = 30 postmenopausal women (age 40–64)	G1: 37 g dark choc + sugar-free cocoa beverage, total flavanol 814 mg G2: low-flavanol chocolate bar + cocoa-free beverage, total flavanol 3 mg	4 weeks 2 weeks washout period	↑ Basal diameter and peak diameter of brachial artery, basal blood flow No changes in body weight, BMI, waist circumference, hip circumference, or WHR No changes in blood glucose, blood lipid profile
Nickols Richardson et al. [28] (USA)	Randomized controlled parallel trial	N = 60 overweight/obese women (age 25–45)	Daily energy-restricted diet with: G1: 236 mL sugar-free natural cocoa beverage per day (272 kJ/day), one 1.45 oz dark chocolate (270 mg flavanol) G2: 236 mL sugar-free cocoa-free vanilla beverage per day (272 kJ/day), two non-chocolate sweet snacks (fruit-flavored licorice stick) (0 mg flavanol)	18 weeks	↓ BW, SBP, DBP, glucose, insulin No change in lipid profile
Basu et al. [21] (USA)	Randomized controlled double-blind cross-over trial	N = 18 obese adults with elevated waist circumference, type 2 diabetes (14 females, 4 males, age > 21)	G1: 20 g cocoa beverage (960 mg polyphenols, 480 mg flavanols) + high-fat fast-food breakfast (766 kcal) G2: 12 g flavanol-free placebo (110 mg polyphenols, <0.1 mg flavanols) + high-fat fast-food breakfast (766 kcal)	6 h 1 week washout	↑ HDL-c, serum insulin No changes in TC, LDL-c, glucose, HsCRP No changes in SBP, DBP, HOMA-IR, small artery elasticity Lower large artery elasticity
Munguia et al. [35] (Mexico)	Randomized controlled double-blind trial	N = 15 overweight with borderline criteria of metabolic syndrome (age 20–60) (11 females, 4 males)	G1: cocoa bean extract powder (80 mg flavonoids) G2: placebo powder (sugar-free, no flavonoids)	4 weeks	↓ BW, BMI, WC ↓ SBP ↓ FBG ↓ TC, LDL-c, HDL-c, TG ↓ Oxidative marker: MDA
Ibeiro-Baraibar et al. [27] (Spain)	Randomized controlled parallel double-blind trial	N = 24 (12 males, 12 females) (age 50–80)	G1: –15% energy-restricted diet + ready-to-eat meals + 1.4 g cocoa extract (645 mg polyphenols) G2: –15% energy-restricted diet + ready-to-eat meals	4 weeks	↓ Body weight in both groups No changes in insulin level, fasting glucose for both groups ↓ TC, TG, LDL-c, HDL-c) in both groups ↓ oxLDL, MPO, ICAM in G1
Lee et al. [50] (USA)	Randomized controlled four-period cross-over trial	N = 31 overweight/obese with elevated LDL-c (13 males, 18 females) (age 30–70)	G1: No treatment food (average American diet) G2: 42.5 g almonds (ALD)G3: 18 g cocoa powder + 43 g dark chocolate (CHOC) (422 mg polyphenols) G4: ALD + CHOC (422 mg polyphenols)	4 weeks 2 weeks washout period	CHOC + ALD ↓ apolipoprotein B ↓TC and LDL-c in G2 Higher FBG in G3 and G4, no changes in insulin, IR, hsCRP Oxidative stress: No changes in all groups (LDL oxidation, urinary 8-isoprostane)
Leyva Soto et al. [34] (USA)	Randomized placebo-controlled double-blind trial	N = 84 young volunteers (47 men, 37 women)	G1: 2 g dark chocolate (70% cocoa) G2: 2 g milk chocolate	6 months	↓ TC, TG, LDL-c ↓ WC ↓ FBG, HOMA-IR ↓ BP

FMD, flow-mediated dilation; BMI, body mass index; BW, body weight; WC, waist circumference; WHR, waist-to-hip ratio; BP, blood pressure; DBP, diastolic blood pressure; SBP, systolic blood pressure; FBG, fasting blood glucose; TC, total cholesterol; TG, triglycerides; LDL-c, low-density lipoprotein cholesterol; HDL-c, high-density lipoprotein cholesterol; CRP, C-reactive protein; HsCRP, high sensitive C-reactive protein; HOMA-IR, Homeostatic Model Assessment for Insulin Resistance; QUICKI, quantitative insulin sensitivity check index; IL-6, interleukin 6; ICAM-1, intercellular adhesion molecule 1; MDA, malondialdehyde. ↓, decreased; ↑, increased.