Table 1.

Description of studies exploring factors of adherence to lifestyle modification programs.

Study	Design	Primary Aim	Subjects	Country of Origin	Ethnicity	Setting	Interventionist	Format and Delivery	Dietary Component	PA Component	Behavioural Component	Duration	Assessment of Factors
Attrition
Teixeira et al., 2004 [38]	I	Weight loss	- 158 free-living participants - All F - Age 48 ± 4.5 - BMI 31 ± 3.8	USA	Non-Hispanic or Hispanic white	Community	Intervention team with physical activity, nutrition, psychology, and behaviour modification experts	Group based plus online follow up - 16 weekly group sessions, 150 min each - 25 participants per group	Reducing energy intake to achieve daily energy deficit (less 300–500 kcal/day)	Increase PA to achieve daily energy deficit (less 300–500 kcal/day).	CBT: Goal setting, self-monitoring, self-efficacy enhancement, relapse prevention, contingency management Social support	16 weeks + online contact or no contact for 1 year	Baseline
Kong et al., 2010 [39]	I	Weight loss	- 51 patients with MetS or pre-diabetes - 65% F - Age 50.8 ± 12.0 - BMI 40.5 ± 9.3	Canada	NA	Clinical: Outpatient clinic in an academic hospital	Nurse, endocrinologist and dietitian	Individual based - 1 session every 6 weeks for 1 year - 90 min for first session - 45 min during each follow up session Group based - weekly seminar - walk-in basis	Nutrition goals e.g., (portion sizes, vegetable and whole grain intake, fat content, snacks, caloric beverages) Food labeling Eating out	Long-term objective: 60 min of moderate PA daily	Goal setting Barriers to change Reinforce behaviour Motivation Emotion management Self-esteem	1 year	Baseline + Weight loss data for 6 weeks
Neve et al., 2010 [46]	L	Weight loss	- 9599 participants of a web-based weight loss program 12-week: 6943 52-week: 2656 - 86%F - Age 35.7 ± 9.5 - BMI 32.9 ± 6.7	Australia	NA	Online, Community	Online support from experts	Individual based - 12 or 52-week subscription participants included - Daily calorie goal - Weekly exercise goal - Weekly weigh-ins - Weekly email with educational information Group based - Online discussion forum - Monthly online meeting with other participants	Calorie-controlled and portion controlled diets developed by dietitians.	Step-by-step workout programs Workout videos featuring the Biggest Loser trainers	SCT Goal setting Self-monitoring	12 or 52 weeks	Baseline
Bradshaw et al., 2010 [37]	RCT	Weight loss	- 119 free living individuals with at least 1 CVD factor - All F - Age 25–65 (mean: 46.3) - BMI Completers: 34.9 ± 5.4 Dropouts: 36.0 ± 6.0	New Zealand	Around 90% New Zealand European	Community	Group 1: Nutritionist and psychotherapist Group 2: Dietitian, psychotherapist and lifestyle activity consultant	Group based - Relaxation response training - Without relaxation response training • 2 h per sessions • 10 initial weekly sessions, then fortnightly and monthly for 8 months	Non-dieting approach (eating regulated by hunger and satiety) Group 1: mindful eating Group 2: low fat diet, food shopping, healthy diet, food variety	Regular PA	Relaxation technique and mindful eating (Group 1 only) Goal setting, self-monitoring, stimulus control (Group 2 only) Body image Enjoyment SCT Cognitive restructuring Coping skills	10 weeks + 8 months (Analysis for first 10 week only)	Baseline
Roumen et al., 2011 [31]	RCT	Prevention of DM	- 147 patients with IGT - 49% F - Age I: 55.0 ± 6.5 C: 58.8 ± 8.4 - BMI I: 29.9 ± 4.2 C:29.7 ± 3.4	Netherlands	Caucasian	Community	Dietitian and exercise trainer	Individual based - First session 4–6 weeks after randomization - 1 session every 3 months for 3 years - 1 h per session	Dutch guidelines for a healthy diet	Increase PA at least 30 min a day, 5 days a week Voluntary exercise program Aerobic exercise training Resistance training	Goal setting	3–6 years	Baseline
Ahnis et al., 2012 [40]	I	Weight loss and maintenance	- 164 patients - 84.1% F - Age Completers: 47.4 ± 11.0 Dropouts: 42.9 ± 11.6 - BMI Completers: 39.6 ± 6.5 Dropouts: 39.5 ± 6.7	Germany	NA	Clinical-Outpatient clinic	Dietitian, psychologist and physiotherapist	Group based - 2 per week in first 6 months - 1 per week in 6–12 months - 2.5 h each	Balanced diet with reduced fat Reduce intake of food with high glycemic index Reduce 500–800 kcal per day Lectures, controlled dialogue, discussion, group work, theoretical and practical exercises (e.g., cooking)	Movement therapy: equipment-based remedial gymnastics, aqua fitness and medical workout, goal to increase 2–3 h of exercise per week. Muscle relaxation: Jacobson’s progressive muscle relaxation	Psycho-educational and behavioural therapy Self-monitoring Relapse prevention Stimulus Control Behavioural substitution Goal setting	12 months	Baseline
Toth-Capelli et al., 2013 [41]	I	Weight loss	- 461 patients - 84% F - Age 18–55 (38% 40–50) - BMI ≥ 30	USA	60% African American	Clinical-Primary Care	Lifestyle counselor and health educator	Individual based - Periodic sessions, 1 per every 3 months - Occasional phone calls in the first month Group based - Biweekly education group	Food guide pyramid Food labeling Healthy meal planning Supermarket tours Healthy cooking Healthy snacking Dining out Healthier shopping	Incorporate PA into daily life	Goal setting Motivational Interviewing Stage of Change	Periodic, time not specified	Baseline
Cresci et al., 2013 [42]	I	Weight loss	- 266 patients - 73% F - Age 43.2 ± 11.9 - BMI 38.8 ± 6.8	USA	NA	Clinical- Outpatient academic clinic	Endocrinologist (first visit) and dietitian	Individual based - Monthly visit	500 kcal/day reduction diet Individualized diet plan	Endocrinologist provide instruction for PA, details not mentioned	Goal Setting Self-monitoring	6 months, follow up at 1, 2, 4, 6 months	Baseline
Michelini et al., 2014 [32]	RCT	Weight loss and maintenance	146 patients I: 73 C: 73 74.7% F Age 45 ± 11 BMI 32.3 ± 3.7	Italy	NA	Clinical- Outpatient clinic	Dietitian, physician and psychologist	Group based +Individual based I group (+CBT): 0–6 months: 7 monthly group sessions 90 min each 6–12 months 1 per every 3 months 30 min each Individual visit 12–24 months: 1 per every 6 months 30 min each Individual visit C group: 0–12 months 1 per every 3 months 30 min each Individual visit 12–24 months: 1 per every 6 months 30 min each Individual visit	Both group assigned hypo-caloric diet: • 15% protein; • 55–60% carbohydrate; • 30% lipid; Booklet explaining food groups and portion size	PA for weight maintenance training	CBT: Goal setting, self-monitoring, relapse prevention	24 months (Analysis for 6 months only)	Baseline
Yackobovitch-Gavan et al., 2015 [43]	I	Weight loss	- 587 members of a health care service 90% F Age 46 ± 11 BMI 31.9 ± 5.5	Israel	NA	Community	Dietitian	Group based - 10 weekly sessions - 90 min each - 12 participants each group	Healthy eating habits	Regular PA	Goal setting Coping	10 weeks	Baseline + weight loss data for 10 weeks
Sawamoto et al., 2016 [44]	I	Weight loss and maintenance	- 119 free living individuals - All F Age Completers: 47.7 ± 1.2 Dropouts: 43.9 ± 2.1 BMI Completers: 31.3 ± 0.5 Dropouts: 32.0 ± 0.9	Japan	NA	Community	Physician and nutritionist	Group based - 34 weekly sessions + 6 biweekly sessions - 90 min per session - 10 participants per session Individual based - 5 sessions over 44 weeks	Reduction of 500 kcal /day More vegetables Reduction of fatty foods Reduction of sweets	Moderate PA e.g., walk 8000–10,000 steps/day Pedometers provided	CBT: Self-monitoring, stress management	7 months (weight loss) plus 3 months (weight maintenance)	Baseline
Susin et al., 2016 [29]	RCT	Management of MetS	- 127 patients with MetS Group 1: 43 Group 2: 43 Group 3: 41 - 59.1% F - Age 49.6 ± 7.8 - BMI 34.9 ± 3.5	Brazil	87% White	Clinical- Rehabilitation Center in an academic hospital	Physical therapist, psychologist, nutritionist and nurse	Individual based - Group 1: Standard MetS clinical management by nurse - Group 2: • Motivational intervention by psychologist • Weekly nutrition appointments with nutritionist • Performance of exercise monitored by physical therapist Group based - Group 3: • Motivational intervention by psychologist • Weekly group meetings with nurse, physical therapist, and nutritionist	Clinical guideline (Not specified)	Clinical guideline (Not specified)	Motivation Stage of Change	3 months	Baseline
Attendance
Helitzer et al., 2007 [33]	RCT	Prevention of DM	75 free living individuals (I group) All F Age 18–40 BMI > 80% BMI ≥ 25	USA	Indian	Community	Female American Indian health educator	Group-based - 5 monthly class-room sessions - 2–2.5 h each	Increase vegetable intake Reduce dietary fat intake Less sugar and healthy fast food strategies	Regular PA	Social support Relapse prevention -sustain healthy lifestyle behaviours SCT concepts e.g., self-efficacy, expectations, emotional coping	5 months	Baseline
Toft et al., 2007 [30]	RCT	Prevention of CVD	897 free living individuals (I group) 61% F Age 30–60 (58% 40–50) Mean BMI Low adherence group: 31.6 ± 0.5 High adherence group: 30.8 ± 0.5	Denmark	NA	Community	Nurse and dietitian	Group-based - 6 meetings in 6 months - 15–20 participants per group - 2 h each. - At 1 and 3 years follow up: participants who were still being assessed as high risk underwent the group sessions again	Decreasing saturated fat, substituting saturated fat for unsaturated fat Increasing intake of fruits and vegetables, and fish	Active at least 4 h/week, no intensity requirements (first 6 months) MVPA at least 30 min/day (at 1, 3, 5 years).	Self-perceived health risk Benefit and barriers Self-efficacy Goal setting Motivational Interviewing	6 months	Baseline
Mata et al., 2010 [47]	L	Weight loss	390 participants of two online weight loss programs B: 139 WW: 251 Al F Age B: 39.2 ± 11.6; WW: 33.7 ± 10.34 BMI B: 27.9 ± 5.26; WW: 29.0 ± 6.00	Germany	NA	Online, Community	NA	Individual based - No common starting point of program - Program length varies and depends on participants’ willingness to pay	B: Recipe-based Low calorie diet plan Shopping lists for every meal. WW: Point-based system	General recommendations on websites. Weight watchers: Point-based system Brigitte: Individualized exercise plan.	Goal setting: B: weight goal; WW: time goal; Self-monitoring of diet and PA Problem solving	8 weeks	Baseline
Self-monitoring
Webber et al., 2010 [45]	I	Weight loss	66 free living individuals All F Age 50.1 ± 9.9 BMI 31.1 ± 3.7	USA	86% Caucasian	Online, Community	Nutrition doctoral student	Individual based - 1 Initial face-to-face session by nutrition doctoral student - 16 weekly internet based sessions - 1 group with additional weekly on-line 1-h chat led by nutrition doctoral student - Message board feature - Self-help resources available on the Web	Dietary goals: - low-fat diet (<25% of calories from fat) - low calorie diet of 1200 or 1500 Kcal Overview of energy balance Safe dietary practices Calorie Book	Exercise goal: 30–60 min of MVPA per day Safety recommendations	Goal setting Motivational Interviewing Self-monitoring	16 weeks	Baseline, 4, 8, 12 and 16 weeks
Krukowski et al., 2013 [34]	RCT	Weight loss	161 free living individuals (I group) 93% F Age 46.2 ± 9.8 BMI 35.7 ± 5.7	USA	69% Caucasian	Online, community	Public health practitioner, clinical psychologist and dietitian	Group based - 24 Weekly online group sessions - 12–18 participants per group - 1 h per session Individual based - Weekly feedback on self-monitoring	Calorie-restricted diet ≤25% fat goal	Graded exercise progressed to 200 min/week of MVPA Pedometers provided	Self-monitoring Stimulus control Problem solving Goal setting Relapse prevention Assertiveness training	6 months	Baseline
Steinberg et al., 2014 [35]	RCT	Weight loss	91 free living individuals (I group) - All F Age 35.4 ± 5.5 BMI 30.2 ± 2.5	USA	African American	Online, community (Interactive obesity treatment approach)	Dietitian	Individual based - Weekly interactive voice response (IVR) calls for self-monitoring of goals - Monthly call with dietitian	≥5 fruit and vegetables/day No fast food No sugar sweetened drinks	Walking 7000 steps/day	Self-monitoring Motivational readiness	12 months	Baseline
Dietary adherence
Aggarwal et al., 2010 [36]	RCT	Prevention of CVD	458 family members of cardiac patients (50% in I group) 66% F Age 49 ± 14 BMI 28 ± 6 (64% with BMI ≥ 25)	USA	65% non-Hispanic White	Clinical-Hospital	Prevention counselor and dietitian (both for I group only)	Individual based - I group: • Stage-matched lifestyle counselling, personalized CVD risk factor assessment • 6 sessions (baseline, 2 weeks,6 weeks, 3, 6 and 9 months) • 30–60 min each - C group: brief, general health message about lifestyle and CVD prevention	Therapeutic Lifestyle Changes (TLC) Diet - Avoid saturated fat, cholesterol, trans fat partially hydrogenated fats - Avoid refined sugars - ≥2 servings fruit/day - ≥3 servings vegetables/day - ≥20 g fiber/day	Moderate PA for at least 30 min per day and 60 min if weight loss was desired	Stage of Change Goal setting Self-efficacy Problem-solving Reinforcing coping skills Reward	9 months	Baseline and 1 year

Key: F: Female I: Pre/post interventions; L: Longitudinal Studies; RCT: Randomized Control Trial; DM: Diabetes Mellitus; CVD: Cardiovascular Diseases; I: Intervention; C: Control; CBT: Cognitive Behavioural Therapy; SCT: Social Cognitive Therapy; IGT: Impaired Glucose Tolerance; MetS: Metabolic Syndrome; B: Brigitte; WW: Weight Watchers; MVPA Moderate to vigorous physical activity; NA: Not Available.