Table 2 Description of automated and manual SMS text messages in NULevel

Motivation

All participants

Every 14 days

Specified number of days since joining study

Automated

Benefits of keeping weight off include better health, self-confidence, new clothes, more energy and a feeling of achievement. Think of what else you’d add to this list. Tell us what motivates you to maintain weight loss.

Resources

Sometimes we intend to be active but conclude ‘I don’t have time for this!’ Do you do this? If so, click: {link: web content}.

Self-regulation

Are you planning to eat out anytime soon? Thinking ahead helps you stay in control: what healthy option from the menu would you enjoy?

Habits

Creating new positive habits to keep weight off takes time; you have to repeatedly do things to build them into your routine (same place, same time, same way). Try to stay positive: habits take time to develop.

Environment and social influences

Eating with supportive family or friends is enjoyable and it can help keep your weight on track too. If you need some inspiration, here are some simple and delicious ideas: {link: web content}.

Behaviour

Sent to

Frequency

Trigger

Automated/manual

Example

Physical activity and eating

All participants

Every 7 days

Specified weekday*

Automated

Please complete your diary today, by following this link: {link:diary}.

Physical activity and eating

All participants

Every 7 days

Participant enters activity and eating goal data

Automated

Thanks for submitting your activity and eating goal diary entries - they help you keep on track to meet your weight goal.

This week you missed your eating goals. Sticking to your plans is key to keeping the weight off! Follow this link {link:plan} to plan how, when and where you can meet your goals next week.

Self-weighing

All participants

Daily (days 1–7)

Participant self-weighs daily

Thanks for weighing yourself - it’s important for keeping the weight off!

Weekly (day 8 →)

You weighed yourself regularly this week: well done and keep it up.

Physical activity and eating

All participants

As required

Participant meets behavioural goals on 3 consecutive wks

Manual

You have mastered your activity goals - congratulations! Why not set yourself some new goals for next week, since you’ve mastered these ones? If so, follow this link to write a new plan {link: edit plan}. If not, you need do nothing.

Weight zone

Sent to

Frequency

Trigger

Automated/manual

Example

All

As required

As required

No weight in 96 hrs

Automated

Don’t forget to weigh yourself today - it’s important for maintaining your weight loss.

All

All

Every 6 weeks

Specific dates

Automated

Have you looked at your weight graph recently? If not, simply log in at {link: login} and click ‘weight’ to view your progress. Log in details not working or forgotten? Please text back and we’ll help!

Green

All participants

Every 7 days

Weight stable in green zone

Automated

This week you managed to stick to your green zone weight: good job.

Yellow/red

As required

As required

≥4 weights at or above yellow/red zone threshold

Manual

We noticed that you regained some of your lost weight and you are now in the yellow/red zone you specified at our support session. Could you please reply to this message to confirm that your last few weights are correct?

Yellow/red

As required

2^nd day in yellow/red zone

Participant confirms accuracy of recent weights

Manual

Okay, thanks for letting us know your recent weights are correct. We’re here to help you get back on track. Would you like us to look at your diary entries and weight to produce some extra, positive, personalized feedback for you?

Yellow/red

As required

As required

≥4 weights below yellow/red zone threshold

Manual

You’re back in the green zone - congratulations for getting your weight back on track!

You’re back in the yellow zone – congratulations!

Yellow/red

As required

2^nd day in yellow/red zone

Participant confirms accuracy of recent weights

Automated

What would you like to do about your regain? You may want to concentrate on just avoiding further regain, or instead to focus on losing the weight you’ve gained. We’re here to support you, whatever you prefer. Please text us your preference.

Red

As required

3^rd day in red zone

Participant confirms wish to lose weight

Automated

You’ve lost weight before, so you know a lot about which methods work for you and which don’t. With that in mind, do you currently have a plan for how you’d like to lose weight? Alternatively, would you like our help in developing one? Please text back to let us know.

Red

As required

4^th day in red zone; unscripted exchanges continue thereafter until weight loss achieved

Participant requests ongoing support in weight loss

Automated

It’s great to hear that you’d like our help in developing a plan to get your weight back on track. You’re an expert on strategies that worked for you before - would you like your new plan to involve these?

We’d like to ask you more about your eating and activity over the last few weeks. This will help pinpoint the causes of your regain.

What would you say has affected your weight the most, recently?

Yellow/red

As required

As required

Participant requests ongoing support in weight loss

Manual

We are glad to hear that you’d like our help in developing a plan to get your weight back on track. This is done most easily with a phone call: please text back CALL ME if you’d like a call, with a suitable day and time. Please text NO CALL if you don’t want us to ring: we’ll continue to support your plan development by SMS.

Green

As required

As required

Weight ≥1 kg below ‘green zone’

Manual

You’re below your green zone weight, congratulations! Why not set yourself some lower thresholds for your yellow and red zone to help keep the weight off? Please text me back with the new weights if you’d like to change them - if not, you don’t need to do anything. Thank you and well done.

Yellow

As required

As required

Participant declines to lose weight following regain

Thanks for telling us you’d prefer to avoid further weight gain, but don’t wish to lose weight at the moment. We are here to support and encourage you every step of the way. In this case, we reset your yellow zone weight to put you back into the green zone, then provide usual weight maintenance support. Are you happy for us to do this?

Seasonal/date-based (e.g. 24 December)

All participants

On seasonal basis

Date

Automated

Many people decide to throw dietary caution to the wind on Christmas Day – don’t worry, we won’t try to dissuade you! It’s only one day of the year. However, if you fancy a delicious, indulgent Christmas Day that’s (surprisingly) under 2500 calories, then look no further: {link: web content}.