Table 1.

Characteristics of studies included in the review.

References	Country	Population randomized (N) and follow-up period	Patients’ characteristics	Type of intervention Lost weight objective Diet advice Physical activity advice Type of intervention Length and duration of interventions	Type of care protocols in CG	Personnel conducting intervention	Weight loss in CG Mean difference (SD) and 95% CI
Greaves39	UK	N = 108 12 months	Age: 40–74 BMI > 28; High CV risk	LWO: Not specified DA: Caloric and fat restriction PAA: To increase TOI: Group-based sessions L-DI: 120’ first month, followed by 90’ session at 1.5, 2, 4, 6 and 9 months	Standard care Pack of written information on CV risk	Nurse and coaches	− 2.04 (6.87) CI (− 3.96; 0.12)
Lin40	USA	N = 124 Outcomes at 6 months Follow up until 12 months	Age > 21 BMI > 27	LWO: Not specified DA: Reduce fat and sugar intake. Portion control PAA: Increase moving and exercise TOI: Individual L-DI: Text messages 3–4 times per day during 6 months	Standard care Initial clinical assessment, personalized weight control plan and PA recommendations. Additional educational material at 6 and 12 months	Dietitian and physician	− 0.2 (3.16) CI (− 1.4; 1.0)
Weinhold33	USA	N = 78 3 months	Age: 18–65 BMI = 25.0 to 50.0 Prediabetes	LWO: 7% reduction DA: Caloric and fat restriction PAA: To increase at least 150’/week TOI: Group-based L-DI: 60’/week during 3 months	Standard care Booklet with strategies for self-regulated weight loss	Dietitians	− 0.4 (0,6) CI (− 0.59; − 0.21)
Oh22	South Korea	N = 32 1 month	Age > 20 Rural women with MetS	LWO: Not specified DA: Caloric and saturated fat restriction PAA: Strength training, rhythmic dance, warm up, and cooldown exercises TOI: Group-based L-DI: 12 sessions, 3 times/week, 120’/session during 1 month	Standard care Educational booklet	Nurses	− 2 (10.90) CI (− 8.59; 4.59)
Alghamdi41	Saudi Arabia	N = 70 3 months	Age > 20 BMI ≥ 30	LWO: ≥ 5% reduction DA: Caloric and CH restriction PAA: To increase TOI: Individual sessions L-DI: 8 visits (15–20’ each) during 3 months	Standard care Printed health education materials regarding diet and PA	Nurses	− 2.8 (4.96) CI (− 3.96; − 1.64)
Blackford44	Australia	N = 401 6 months	Age: 50–69 Rural adults with, or at risk of MetS	LWO: Not specified DAA: Diet intervention with motivational support PAA: To increase TOI: Home-based: printed and interactive online material LDI: Self-management during 6 months	Waitlisted to receive the programme after post-test data collection	Home-based	1.1 (21.95) CI (− 2.29; 4.49)
Fernández-Ruiz35	Spain	N = 74 12 months of intervention, and 1-year follow-up post-intervention	Age: not defined BMI = 25.0–29.9 or BMI > 30	LWO: Not specified DAA: Modification of unhealthy dietary habits PAA: To increase: stretching exercises followed by moderate aerobic work TOI: Group-based L-DI: Monthly session (60’) for educational treatment. Four sessions (40’) of PA every week. Monthly session (6’) of cognitive behavioural therapy	Standard care	Physicians, nurses, nutritionists and psychologists	− 0.2 (12.35) CI (− 4.18; 3.78)
Bo36	Italy	N = 335 1 year	Age: 45–64 Adults with MetS	LWO: Not specified DA: Individually prescribed diet PAA: To increase 150’/week TOI: Individual and group-based L-DI: 5 sessions of 60’: 1 individual session and 4 grouped	Standard care	Family physicians and dietitian	1.63 (6,17) CI (0.83; 2.42)
Duijzer34	Netherlands	N = 316 18 months	Age: 40–70 High risk of type 2 diabetes	LWO: < 5–10% DA: Tailored dietary advice PAA: To increase at least 30’/day, 5 days/week TOI: Individual and group-based L-DI: 5 to 8 individual consultations and one group session	Standard care	General practitioners, practice nurses, dieticians and physiotherapists, sport coaches	− 0.4 (3.7) CI (− 1.06; 0.26)
Christensen29	Denmark	N = 144 12 months (results of the first 3 months)	Age: 18–40 (BMI > 25 or body fat % > 33) Age > 40 years (Body fat % > 34) Female health care workers	LWO: Not specified DA: Caloric restriction PAA: To increase TOI: Individual and group-based L-DI: 180’/week	Standard care Monthly two-hour oral lecture	Sport instructors	0.68 (2.37) CI (− 0.02; 1.38)
Kandula42	USA	N = 63 6 months	Age: not defined Participants with at least one atherosclerotic CV risk factor, including obesity	LWO: Not specified DAA: Fat and salt restriction PAA: To increase 150’/week of moderate intensity TOI: Group-based classes and individual follow-up telephone support calls L-DI: weekly group classes (60–90’) and individual telephone support during 4 months	Standard care Translated print education materials about atherosclerotic CV risk and healthy behaviours	Dieticians	− 0.2 (3,13) CI (− 1.14; 0.78)
Thiabpho30	Thailand	N = 60 4 months	Age: 30–50 (BMI)⩾27.5 With no non-communicable disease	LWO: Not specified DAA: Caloric restriction and balanced diet PAA: To increase a minimum of 150’/week of moderate exercise TOI: Group-based L-DI: During 4 months 12 sessions (90–120’), once a week for the first eight weeks and then every two weeks until the 16th week	Standard care	Nurses	− 0.7(1.4) CI (− 1.20; − 0.20)
Cai38	China	N = 480 24 months	Age: ≥ 60 BMI ≥ 28	LWO: Not specified DA: Caloric, fat and sugar restriction PA: To increase TOI: Group-based and individual based interventions L-DI: Group-based sessions (120’/week the first 12 months; 120’ monthly the following months	Standard care 2-h education sessions every 2 months	Dietitians	− 0.03 (2.51) CI (− 0.37; 0.31)
Nanri28	Japan	N = 107 6 months	Age: not defined Men diagnosed with MetS	LWO: Not specified DA: Dietary change behaviours PAA: To increase TOI: Individual L-DI: Session at baseline and at 3 months	Standard care Leaflet at the baseline	Nurses	− 0.3 (7.81) CI (− 2.4; 1.8)
Maruyama31	Japan	N = 111 4 months	Age: 30–59 Male office workers with MetS risk factors	LWO: Not specified DA: PAA: To increase TOI: Individual and group-based L-DI: Individualized assessment and collaborative goal setting (20’ and 10’ respectively) plus 2 individual counselling sessions and monthly website advice during the 4-month period	Standard care	Registered dietitian and physical trainer	− 0.80 (2.2) CI (− 1.50; − 0.10)
Share23	Australia	N = 43 3 months	Age: 18–30 Women with abdominal obesity [waist circumference (WC) ≥ 80 cm], and who were physically inactive	LWO: Not specified DA: Dietary change behaviours without caloric restriction PAA: To increase 2 session/week TOI: Group-based L-DI: Weekly nutrition education and group cognitive behavioural therapy (60’)	Waitlisted to receive the programme after post-test data collection	Qualified exercise scientist, dietitian and counsellor	− 3.60 (18.67) CI (− 13.20;6)
Moss21	UK	N = 60 Intervention 12 weeks (3 months) and follow-up until week 26. (6,5 months)	Age: 18–85 Obese patients (BMI > 30) with at least moderate OSAHS	LWO: Not specified DA: Advice based on the principles of the eat well plate PAA: To increase: supervised exercise sessions TOI: Group-based L-DI: 3 sessions/week, then 2/week during weeks 5 to 8 and then to 1/week during weeks 9 to 12	Standard care Basic written lifestyle advice, and a weight loss leaflet	Exercise physiologist	0.2 (21) CI (− 8.11; 8.51)
Puhkala32	Finland	N = 113 12 months of counseling + 12 months of follow up	Age: 30–62 Male truck or bus driver, waist circumference ≥ 100 cm, absence of diabetes and little PA	LWO: < 10% reduction DA: Advice based on the principles of the eat well plate PAA: To increase 30’of moderate-intensity walking TOI: Individual L-DI: during 12 months: 6 individual sessions of 60’ and 7 telephone contacts of 30’	Standard care Advice and telephone contacts	Nutritionists and physiotherapist	− 2.5 (5.9) CI (-4.02; − 0.98)
Anderson37	UK	N = 560 12 months	Age: 50–70 Women with excess body weight BMI > 25	LWO: < 7% reduction DA: Personalised diet advice PAA: To increase TOI: Individual L-DI: During 12 months 2 individual sessions (60’ and 45’) in the first 3 months and then 9 (15’) support calls over the following 9 months	Standard care	Nurses	− 1.2 (5.0) CI (− 1.8; − 0.6)
Röhling45	Germany	N = 30 1 year	Age > 18 BMI ≥ 25	LWO: Not specified DA: Low-carbohydrate nutrition and meal replacement therapy PAA: To increase TOI: Group-based L-DI: During 3 months intervention: 7 theoretical sessions and two practical modules of 90’ each, and: 4 telephone calls (20–30’each) monthly	Waitlisted to receive the programme after post-test data collection	Nutritionists, exercise scientists, biologists, physicians and psychologists	− 1.4 (4.18) CI (− 3.3; 0.6)
Jordi Salas Salvadó43	Spain	N = 626 12 months	Age: 55–75 Patients without CVD, overweight/obese (BMI > 27 and < 40) and with MetS	LWO: < 5–10% reduction DA: Mediterranean diet PAA: To increase TOI: Individual and group-based L-DI: During 12 months: group sessions and telephone calls once per month	Standard care Advice about Mediterranean diet monthly without specific advice for increasing PA. Group sessions and telephone calls every 6 months	Doctors, dietitians and nurses	− 0.7 (4.07) CI (− 1.1; − 0.3)
Pablos46	Spain	N = 97 8 months	Age: 20–70 Adults with BMI > 25, no regular PA living in a low median household income census tract	LWO: Not specified DA: Personalized diet advice PAA: To increase TOI: Individual and group-based L-DI: 8-month intervention: 3 sessions/week of PA (140–180’) and 1 session/week of nutrition or psychological support (60’)	Waitlisted to receive the programme after post-test data collection	Doctors, nutritionists, nurses, psychologists and trainers	− 0.13 (21.48) CI (− 8.46; 8.20)

BMI Body mass index; CG Control group; CVD Cardiovascular disease; MetS Metabolic syndrome; PA Physical activity; OSAHS Obstructive sleep apnoea hypopnoea syndrome; SD Standard deviation; LWO Lost weight objective; DA Diet advice; PAA Physical activity advice; TOI Type of intervention; L-DI Length and duration of interventions.