Check in weekly for three months, then fortnightly

Run nutrition coaching check-ins weekly for 12 weeks, then fortnightly

Nutrition coaching check-ins should be frequent at the start and predictable afterwards: weekly for the first 12 weeks, fortnightly after that, with a channel the client can use in between. That shape is not a preference. It compresses what the Diabetes Prevention Program and Look AHEAD both ran, dense at the start and thinner later, and both papers say why.

The question underneath the cadence question is usually time. A weekly call with 20 clients is most of a working day, so the honest answer has to say when the gap may widen and what has to keep running when it does.

The trials that worked front-loaded the contact

The Diabetes Prevention Program gave every participant a named lifestyle coach and a 16 session core curriculum, to be finished inside the first 24 weeks. Sessions ran from 30 minutes to an hour, one to one. After the core, the protocol asked for a face to face visit at least once every 2 months for the rest of the trial, with a phone call at least once between visits.

Look AHEAD, with 5,145 participants, ran heavier. The table puts the two side by side.

Both start dense and thin out. Neither one stops.

Weekly for a whole year buys very little

The Look AHEAD authors set out the evidence their schedule came from. Weekly treatment of 16 to 26 weeks is standard in the behavioural management of obesity, and weekly treatment carried on for up to a year produces only marginally greater weight loss than 6 months already produced.

That is the argument for stepping down. It is also the argument against stepping down in month 2, because the marginal return only goes flat after the first block of weekly work has happened. Spahn and others drew a similar boundary from a different angle: across the 87 studies they included, the evidence was particularly strong for intensive cognitive behavioural therapy of intermediate duration, 6 to 12 months, in patients with type 2 diabetes.

Never let the gap between two contacts reach a month

From year 2, Look AHEAD kept contact going by telephone, mail and e-mail as well as by visits. The paper gives the reason in one line.

RCTs have shown that at least twice-monthly contact, using these modalities, significantly improves the maintenance of lost weight.

Twice monthly is a floor, and it is a floor that an e-mail clears. A fortnightly check-in is already above it. A monthly call is below it unless you put something in the middle of the month, which is why the calendar reminder matters more than the format of the contact.

When you stretch the cadence, the logging goes first

Burke, Wang and Sevick reviewed 22 studies of self-monitoring published between 1993 and 2009. Describing one group that counted a week's diary as complete only when it recorded at least half the recommended energy intake, they name the pattern.

Similar to what has been reported in the literature ... there was a gradual decline in self-monitoring adherence, which worsened when the treatment sessions decreased in frequency.

The size of that decline is worth seeing. In one 18 month trial in the review, the share of participants reporting a weight each week fell from 84% to 56% in the face to face group, and from 82% to 55% in the internet group. Both arms lost roughly a third of their weekly weights over the study.

So when you halve the cadence, do not halve everything with it. Move the call to fortnightly and keep the data request weekly: the weight, the days logged, one sentence on the week. The call is what costs you an hour. The request costs you nothing and is the thing the evidence links to the result.

Group contact is cheaper, one to one contact is what keeps people

Look AHEAD ran its first six months mainly in groups, three group sessions against one individual meeting a month. Cost is part of the reason the paper gives, along with the social support and competition a group supplies. The paper is candid about why the individual meeting survived the arithmetic. Several Look AHEAD members had served as interventionists on the Diabetes Prevention Program, and believed individual contact was critical to retaining participants over a multi-year intervention. The Diabetes Prevention Program itself primarily used an individual model of treatment rather than a group-based approach, and named each participant's coach on the day they joined.

A solo coach rarely has the group option, so the trade is between a live call and a written contact. Keep the live one to one and let the written one carry the volume.

On demand is a channel, not a cadence

"Message me whenever you need me" reads as generous and behaves as nothing. The client who needs the check-in most is the one who will not send the message, and a coach with 20 clients cannot notice an absence that has no date attached to it.

Keep the open channel, and keep a scheduled contact underneath it. The scheduled one is what turns a silence into a signal on a particular Tuesday, which is where what to do when a client goes quiet begins.

A 15 minute check-in holds five things if you read first

The Diabetes Prevention Program ran a fixed shape inside every core session: a private weigh-in, a review of the self-monitoring records, a new topic, the participant's own barriers named out loud, and an action plan for the next session. Fifteen minutes holds that if the reading happens first.

1. Read the week's records and weight before the call, not during it.
2. Name one number that moved and one that did not.
3. Name the barrier that showed up this week, as an event with a date.
4. Teach one small thing, and only one.
5. Write the action for next week where the client can see it.

Look AHEAD did the same thing at the programme level: weight and weekly activity minutes went into a tracking system at every visit, and the system produced progress reports. A spreadsheet does that job for 20 clients.

The step down is what makes 20 clients fit in one week

A weekly 15 minute call with 20 clients is 5 hours of calls before any preparation, which is why weekly for everyone falls over in month 4.

Now run the same 20 clients with a step down in place. Say 8 are inside their first 12 weeks and 12 are past it. That is 8 weekly calls plus 6 fortnightly calls falling due, so 14 calls, or 3 hours 30 minutes. The other 6 clients get a written contact that week, which keeps everyone above the twice monthly floor.

The step down is not a concession to the client's patience. It is what makes the first 12 weeks affordable for the next person who signs up.

We step down at 12 weeks and never let a month pass

Our recommendation: weekly check-ins for the first 12 weeks, fortnightly after that, and never a gap of a month between two contacts. Set the step down date on the day the client starts, so it is a date in a calendar rather than a decision you make when you are tired.

Monthly becomes defensible later than most coaches think. Wing and Phelan report that once a loss has been held for 2 to 5 years, the chance of longer-term success greatly increases, and that is the client you can see every 4 weeks. A client in month 7 is not that client.

A check-in only pays for itself if you can act on it the same day, and the plan rewrite is the part that eats the evening; we built Peas & Pans to make that part quick. Put the first step down date in the calendar now, and the cadence will hold without you deciding it again every week.