Your first six months of maintenance

One

The scale cannot see the thing that matters

Imagine someone who weighs 75kg this year and 75kg next year. By every app and every chart, they maintained perfectly. Now imagine that across those twelve months they lost four kilos of muscle and gained four kilos of fat. The scale never moved. Almost everything else did.

This is why "maintaining" is a harder thing to measure than it sounds. A steady weight is genuinely good news. It is just not the whole picture, and it is not self-evidently the picture you want.

So the question worth asking every few months is not only am I holding my weight, but am I holding what my weight is made of.

Two

What you are actually protecting

All weight loss costs some lean tissue. Not just fat comes off, whether you lose weight through medication, surgery, or a strict diet. That is normal and it is not a sign anything has gone wrong.

How much is genuinely debated. Analyses of the big GLP-1 trials have reported figures around 39 to 40 per cent of total weight lost coming from lean mass. A network meta-analysis pooling 22 randomised trials puts it closer to 25 per cent. And in those same trials, the proportion of lean mass to total body mass improved, because people were losing a great deal of fat at the same time. A 2026 paper in Cell Reports Medicine argues the lean mass loss on these medications is not disproportionate compared with other forms of weight loss.

Here is why defending it matters practically. Muscle is metabolically active tissue, so it drives a meaningful share of the energy you burn at rest. Lose lean mass and your maintenance calories quietly fall. Holding your weight then requires eating less than it used to, which is harder to sustain, which makes drifting back up more likely. Muscle loss is not a side effect of regain. It is one of the mechanisms of it.

Three

Protein: how much, and why it is the lever

Protein is the single most studied thing you can change here. A meta-analysis of 28 trials covering 1,989 people found that higher protein intake during weight loss significantly reduced the loss of muscle mass. The useful range that comes out of that literature is roughly 1.2 to 1.6 grams per kilogram of body weight per day, compared with the 0.8g/kg that gets quoted as a general minimum.

For someone at 80kg that is about 96g to 128g of protein a day. It is more than most people eat by accident, and it is noticeably harder to reach when your appetite is suppressed, which is exactly the problem: the medication that makes losing weight easier also makes hitting your protein harder.

• Put protein first in the meal, while you still have appetite to spend. The vegetables can wait.
• Spread it out. Three moderate servings land better than one large one, especially on a small appetite.
• Have two or three protein-heavy meals you can make without thinking. Repeatability beats variety here.
• Liquid protein counts, and often goes down when food will not.

Four

Resistance work is the signal

Protein is the raw material. Resistance training is the message telling your body to keep the muscle rather than let it go. Neither works nearly as well alone.

The best single result to know: in a randomised trial of adults aged 55 to 80 losing weight, the group eating around 1.3g/kg of protein and doing resistance training three times a week did not merely lose less muscle. They gained fat-free mass, about 0.6kg, while still losing weight overall.

Twice a week is the floor worth defending. That is deliberately below the three sessions in the trial, because two is the number people actually keep doing in month five, and a habit you keep beats a protocol you abandon.

• Bodyweight counts. Sit-to-stands, press-ups against a wall or a worktop, carrying shopping in both hands.
• Cover legs, push and pull. That is most of the body in three movements.
• Progress by making it slightly harder over time: more reps, slower, heavier, or a longer hold.
• Soreness is not the goal and is not the measure. Turning up twice a week is.

Five

Weigh the trend, not the day

Body weight moves a kilo or more day to day for reasons that have nothing to do with fat: salt, water, hormones, what time you went to the loo. Judging maintenance on a single morning's reading means reacting to noise, and reacting to noise is exhausting.

Use a band instead of a point. Pick the weight you are actually holding at, which is often not the target you originally set, and give it room either side. Around two per cent of your body weight is a sensible width: roughly 1.5kg at 75kg, roughly 2.5kg at 125kg. Inside the band is maintaining. That is the whole rule.

• Weigh at a repeatable moment, then look at the fortnightly average rather than today's figure.
• One high morning is weather. A trend leaving the band for a few weeks is a signal.
• Measure your waist every month or two. It moves when the scale does not, in both directions.
• Notice what you can do. Stairs, shopping, getting off the floor. Function is lean mass you can feel.

Six

If you come off the medication

You deserve the real numbers rather than a reassuring version of them. In the extension of the STEP 1 trial, 327 people who had lost an average of 17.3 per cent of their body weight by week 68 came off treatment. By week 120, they had regained about two thirds of it, sitting around 5.6 per cent below where they started. The improvements in blood pressure, blood sugar and cholesterol largely drifted back toward baseline alongside the weight.

That is not a reason to be frightened, and it is not a verdict on you. It is evidence that these medications treat an ongoing condition rather than cure it, and that stopping the treatment tends to bring back what the treatment was holding off.

What appears to shift the odds is unglamorous and entirely within reach: the protein, the twice-weekly resistance work, and the habits you kept while the medication made keeping them easy. Muscle you still have is maintenance calories you still have.

The short version

If you only remember four things

• The number holding still is the check. Protecting muscle is the job.
• Aim for 1.2 to 1.6g of protein per kilogram of body weight a day.
• Resistance work twice a week, bodyweight included. It is the signal to keep what you have.
• Judge yourself on a band and a trend, never on one morning.