What do you do when a client's weight loss plateaus?

Is it really a plateau?

Day-to-day changes in body weight are normal. Salt, carbohydrate, bowel contents, training soreness and the menstrual cycle all move water around. A client who weighs in once a week can land on a high day and read it as a stall.

Look at the trend, not the last number. Compare weekly averages, or the same day of the cycle month to month, and check the waist measurement too. If waist measurements are still trending down while weight is stable, that can suggest progress is continuing despite little change on the scale, so avoid reacting to weight alone.

• A short-term stall: consider normal fluctuations before changing the plan.
• Several weeks flat, with other relevant measures also unchanged: review adherence, intake, activity and the current energy target.
• Weight changes after starting or increasing training: remember that temporary changes in fluid balance can affect scale weight.

Why weight loss slows

Energy needs fall as weight falls. A deficit that was 500 kcal (about 2,100 kJ) a day at 95 kg is smaller at 85 kg, because a lighter body burns less at rest and moving around. Hall and colleagues' model in The Lancet puts it plainly: each lasting change in intake of about 100 kJ (24 kcal) a day eventually moves weight by about 1 kg, and it takes around a year to get halfway there. As the client gets lighter, the same calorie target creates a smaller deficit, so weight loss usually slows.

Intake can also drift. Portions grow, weekend meals stretch, and logging may become less accurate over time. In a classic NEJM study of 10 people who reported eating under 1,200 kcal a day despite difficulty losing weight, measured intake was on average 47% higher than reported and physical activity was overreported by 51%. Energy expenditure was close to that predicted from body composition. This was a small, highly selected group, so these figures shouldn't be assumed to apply to every client, but the study illustrates why reported intake and activity are worth reviewing.

Metabolic adaptation is also real. During weight loss, energy expenditure can fall beyond what would be expected from the change in body size alone, while changes in appetite can make continued restriction harder. The size and persistence of this adaptation vary between individuals. Planned periods at maintenance can be useful for adherence or to provide a break from energy restriction, but they aren't required to ‘reset’ metabolism.

Work through the checks in order

1. Recalculate from current weight. If the target was set at the start, reassess estimated energy requirements using the client's current weight and circumstances.
2. Audit a few days of logging with the client. Look for oils, drinks, sauces, tastes while cooking and unlogged weekends. Ask for three days of careful weighing if they are willing.
3. Check steps and activity. Daily movement can fall without the client noticing, particularly during energy restriction. Compare current activity with their usual baseline.
4. Check sleep, stress, new medication and the cycle. Any of these can mask fat loss with water, or change appetite.
5. Only then consider reducing energy. Make a modest adjustment based on the client's current intake, estimated requirements and progress, then reassess the trend over the following weeks.

Keep protein up while you cut: it protects lean mass and helps with fullness. The numbers are in how to calculate protein needs.

When to hold rather than cut

Cutting further isn't always right. Hold at the current target, or consider a period at maintenance, when the client reports poor sleep, constant hunger, falling training performance, a low mood, or a life event that has taken over. A maintenance phase is a chance to practise the habits that help maintain weight loss, and some clients may find it easier to resume a deficit afterwards.

Also question the goal itself. If a client has achieved a clinically meaningful amount of weight loss and reached a weight they can sustain, maintaining it can be a good result. Holding weight is a skill that most people have never practised.

Some stalls aren't yours to fix alone. Rapid unexplained change, a history of disordered eating, suspected thyroid problems, or a medication change (including GLP-1 dose changes) needs the client's doctor involved. For clients on GLP-1 medication, see protein needs on GLP-1 medication.