Table 5 Details of content and delivery of commitment devices

Balk-Møller 2017 [38]

Commitment device- Pledge (online/app commitment) 1 at baseline, Pledge 2 at 22 weeks. Weight loss subgroup chose one of: lose weight, eat healthier, improve physical fitness, stronger body, maintain healthy lifestyle.

Intervention content-self-reporting of diet and exercise, personalized feedback, suggestions for activities and programs, practical tips.

Intervention group:1.1/1.3, 1.9, 2.2, 2.3, 2.4, 2.5, 3.1, 4.1, 10.1, 10.3.

Control: None

Online/app

No

Weight (O), waist circumference (O), % body fat body composition monitor (O).

Black 1983 [43]

Commitment device- Behavioural contract. Contract to record food, non-routine PA for 2 weeks in first session. Four contracts used: 1) altering eating habits 2) increasing activity 3) combined contract 4) maintenance or continuation of weight loss

Intervention content- Limited information provided. Adapted from Stuart & Davis ‘slim chance in a fat world’ (1972) - no further information available.

All groups: 1.1, 1.8, 2.,3 2.6

Husband Contracting group: as above plus 3.1

Spouse or health professional, dependant on group assignment

Yes

Weight (O)

Clifford 1991 [36]

Commitment device - Behavioural contract. Individual behavioural health self-contracts, no further info.

Intervention content- A self-directed change (SDC) intervention that applied cognitive-behavioural techniques to exercise adherence, weight reduction/maintenance, and stress management.

Intervention groups: 1.8, 1.1, 3.1, 1.2,

Control group: None

Not specified

Yes

Weight (O), body composition (fat) (O) exercise adherence questionnaire (SR) and Cardiovascular fitness (oxygen consumption levels) (O)

Craighead 1989 [45]

Commitment device - Behavioural contract. Signed an exercise contract to complete at least 90 min of any exercise of their choice per week.

Intervention content- ‘standard behavioural weight control procedures as described in Ferguson (1975) and Mahoney & Mahoney (1976).’ No further information available.

Intervention group: 1.1, 1.8, 2.2, 2.3, 2.5, 2.6, 4.1, 10.4.

Contract only group: 1.1, 1.8, 2.2, 2.5, 4.1.

Not specified

No

Weight (O), Body fat (O), Fitness (step) test (O), Eating inventory questionnaire (SR)

Dubbert 1984 [46]

Commitment device - Behavioural contract, commitment. Contract/commitments by male spouse of female participants to make one or two changes to facilitate efforts

Intervention content- ‘4-week educational phase about weight reduction, nutrition, techniques for controlling eating and safely increasing exercise, coping with negative emotions and self-defeating cognition, asserting oneself to obtain the necessary support from significant others, and the importance of keeping records and setting goals … All advised to cut back on calorie intake while increasing daily activity.’

All groups: 1.1, 1.2, 1.3, 2.2, 2.3, 2.4, 2.7, 3.1.

Couples group: As above, plus 1.8, 1.9, 10.4.

Not specified

Unclear

Weight (SR)

Franzini 1980 [42]

Commitment device - Behavioural contract

3 contracts 1) membership contract 2) self-contract 3) significant person contract.

Intervention content- Standard behavioural modification treatment package (Stuart 1971), which includes increasing aerobic walking and monitoring and improving dietary habits.

Intervention group: 2.2, 2.3, 4.2,5.1, 10.3, 10.4, 10.6.

Contract group: As above, plus 1.1, 1.3, 1.8.

Control group: None

Not specified

Yes

Weight (O), % body fat (skinfold test) (O)

Kegler 2016 [41]

Commitment device - Behavioural contract

Healthy actions contract, building from 2 to 6 actions over 16 weeks.

Intervention content- Social–cognitive theory informed intervention targeting home food and activity environments to reduce energy intake and increase physical activity, included a tailored home environment profile, goal setting.

Intervention groups: 1.1, 1.8, 12.1, 12.6.

Control group: 1.1, 2.3, 5.1, 12.6

Health coach

Yes

Weight (O), Energy intake (recall questionnaire) (SR), Physical Activity (Accelerometer) (O)

Maruyama 2010 [40]

Commitment device - Behavioural contract, consisting of a commitment sheet- dietary (food groups) and physical activity (steps).

Intervention content- Monthly contact with trained dietician and physical trainer, including goal setting and action planning sessions and self-reporting diet & physical activity, followed by progression to online support.

Intervention group: 1.1, 1.8, 1.4, 2.3, 2.2, 3.1,

Control group: None

Not specified

Yes

Dietary adherence (SR), PA adherence – pedometer (O), Weight / BMI (O)

Nyer 2010 [38]

Commitment device - Public commitment (outcome)

1) Weight loss goal and name displayed in glass cabinet for 16 weeks.

2) As above, but for 3 weeks only.

3) No public commitment.

Intervention content- weight loss program ‘focus was on helping clients to transform their lives by identifying sustainable means of increasing caloric expenditure while reducing caloric input within the context of their lives.’ No further information.

Intervention groups: 1.3, 2.5

Control group: 2.5

Staff /peers at health centre (public)

No

Weight – not reported (O)

% weight loss goal achieved (O)

Ureda 1980 [44]

Commitment device - Behavioural contracts. Three contracts: 1) Program participation, 2) completion of a nutrition education workbook, 3) establishment of weight-controlling regime.

Intervention content- ‘behavioural self-management/self-help

weight control program, whereby each participant was taught the skills and knowledge necessary to formulate and implement an individually tailored diet, meal pattern, and exercise regimen sufficient to achieve a weight loss of one-to-three pounds per week.’

All groups: 1.8, 1.1, 10.7

None or peer/ relative/ friend dependant on group

No

Weight (O)