Who recomposition works forStrong evidence
Losing fat and building muscle together is what usually happens when people new to lifting start strength training, especially with fat to lose. In 114 trials of 4,184 people with overweight or obesity, strength training alone added about 0.8 kg of lean mass and took off about 1 kg of fat, compared with not training, and the results held across ages and sexes. In a pooled analysis of 130 untrained older women who trained three times a week for 24 weeks on their usual diets, muscle rose by about 2 to 5% while fat fell by about 2 to 4%. In healthy adults, strength training alone trimmed about 1.5 percentage points of body fat across 58 studies.
Sources 16, 17, 18
Slower if you're lean and experiencedEmerging evidence
It can happen in trained people too, as a narrative review sets out, but more slowly and less reliably. In 6 studies of lean, resistance-trained athletes on a diet, body fat fell in every group, but most groups also lost some fat-free mass; the few that kept or gained it mostly had more body fat, a smaller cut or new training, and one ate the most protein, 2.5 to 2.6 g per kg a day. And over 21 weeks of the same training, untrained men grew their thigh muscles by 5.6% while strength athletes didn't grow at all (8 men in each group).
Sources 19, 20, 21
Lifting is the baseStrong evidence
Strength training is what adds or keeps the muscle. In 119 adults with overweight or obesity over 8 months, aerobic training took off more fat and weight, strength training added more lean mass, and doing both did both. When people eat less, strength training keeps muscle that dieting alone loses: about 0.8 kg more lean mass in an overview of reviews, and in 6 trials in older adults with obesity, it prevented about 93% of the lean mass lost through eating less. More weekly sets build more muscle, so the sets rise from week 5.
Sources 22, 23, 24, 25, 26
A small calorie cut, or noneEmerging evidence
If you have fat to lose, eat about 300 to 500 kcal a day less than your maintenance figure from our calories calculator, aiming to lose about 0.5% of your body weight a week, or a little less. If you're already a healthy weight and mainly want more muscle, eat at maintenance: the training does the work.
That 300 to 500 kcal is our editorial range, smaller on purpose than the NHS's 600 kcal a day for weight loss and its 0.5 to 1 kg a week. We set it inside two findings. In a meta-regression of training trials, a deficit of about 500 kcal a day stopped lean-mass gains on average, though strength still rose. And in one trial of 24 elite athletes lifting four times a week, those aiming to lose 0.7% of their body weight a week gained 2.1% lean mass, while those aiming for 1.4% (they managed about 1%) gained none. Nobody has tested this range directly for recomposition.
Sources 27, 28, 29, 30
Protein: the calculator's building-muscle settingEmerging evidence
Use our protein calculator's building-muscle setting rather than its weight-loss setting, because this plan aims to build muscle as well as lose fat: under 65, that's 1.6 to 2.2 g per kg of body weight a day. With a BMI of 30 or more (27.5 or more for some ethnic backgrounds), use its figure for the weight at a BMI of 25, and with kidney disease, its kidney setting and your renal team's advice. Spread it over three to five meals.
The evidence points that way without settling it. With training, extra protein stopped adding muscle at about 1.6 g per kg a day across 49 trials, and on calorie-restricted diets, higher protein kept about 0.4 kg more lean mass and took off about 0.9 kg more fat across 24 trials. The trial most often quoted for recomposition used an extreme 40% calorie cut, six hard sessions a week and young men: in 4 weeks, 2.4 g per kg gained 1.2 kg of lean mass, against 0.1 kg on 1.2 g. The best intake during a modest cut like this plan's hasn't been tested.
Sources 31, 32, 33
Cardio's jobStrong evidence
Cardio adds to the fat loss: each 30 minutes a week took off about 0.5 kg and half a centimetre of waist in 116 trials of adults with overweight or obesity, and steady and interval training took off the same fat when they used the same energy. Aim for about 150 minutes a week, counting brisk walks. The plan holds it there, rather than building to the weight loss plan's 200 to 250 minutes, so you recover for the strength days (our choice).
Sources 34, 23, 35
SleepEmerging evidence
Short sleep shifts what you lose from fat to muscle. In 10 adults dieting for 14 days, sleeping 5.5 rather than 8.5 hours cut the fat lost by more than half and raised the fat-free mass lost, and in 36 adults on an 8-week diet, sleeping about an hour less on 5 nights a week cut the share of fat in what they lost. The NHS says adults need 7 to 9 hours.
Sources 36, 37, 38
Measure the right thingsStrong evidence
Your weight can stay much the same while you lose fat and gain muscle, so judge progress by your waist, photos and lifts. Measure your waist every 4 weeks the NHS way: midway between your lowest rib and the top of your hip bone, breathing out naturally. NICE (the National Institute for Health and Care Excellence) counts a waist under half your height as healthy for adults with a BMI under 35. Take photos in the same light and pose, and keep your training log.
Bathroom body-fat scales aren't up to it: three smart scales were 2.2 to 4.4 kg of fat out against a body scan, 15 bioimpedance devices read from 3.5 percentage points too low to 11.7 too high, and NICE says not to use bioimpedance instead of BMI. Some devices tracked change over 12 to 16 weeks better, so one used the same way, at the same time of day, can show a rough direction at most. Even research methods often disagree about how much muscle has grown.
Sources 39, 40, 41, 42, 43
Honest timelinesEmerging evidence
Recomposition trades speed for doing both: fat comes off more slowly than with a bigger cut, and muscle grows more slowly than when you eat enough, because a calorie deficit held back muscle gains in pooled trials. The trials ran from 4 to 24 weeks, and the biggest change came from 4 extreme weeks of six hard sessions a week and a 40% cut. More typical are just under a kilo of lean mass over a programme in people with overweight or obesity, and a few per cent more muscle over 24 weeks in older women. People differ hugely, so compare yourself with your own week 1; nobody can promise you a date or a look.
Sources 27, 33, 16, 17, 44
Coming back after a breakMixed evidence
Some of the strength you built before lasts through long breaks, so your weights may climb quickly. What happens to muscle is less clear: in one small trial in women, muscle fibre size was largely kept after 30 to 32 weeks off, while in another, muscle size was back to where it started after 20 weeks, and a previously trained leg didn't regrow faster than an untrained one, though that trial couldn't fully test "muscle memory".
Sources 45, 46
How much training this isStrong evidence
Counting direct sets in the build phase, this plan gives about 7 to 8 hard sets a week for the chest, 9 for the back, 4 to 5 for overhead pressing, 12 for the quads and 12 for the glutes and hamstrings in weeks 3 and 4, and from week 5 about 9 for the chest, 10 to 11 for the back, 15 for the quads and 13 to 14 for the glutes and hamstrings, averaged over two weeks; the arms work through the presses and rows.
More weekly sets build more muscle, with diminishing returns that arrive sooner for strength than for size. The 2026 ACSM position stand saw extra growth from about 10 or more sets per muscle a week, and a review of time-efficient training suggests about 4 hard sets a week as a reasonable floor for busy people.
That clears the 4-set floor for every muscle, and reaches 10 or more for the back and legs from week 5, when the extra sets go in.
Sources 1, 25, 26, 8
Full body or split: similar resultsStrong evidence
When weekly sets are matched, full-body and split routines give similar strength and muscle gains, and how often you train a muscle matters little for growth. So the choice is about your schedule, session length and what you enjoy.
Sources 47, 48, 26
Cardio does not cost you muscleStrong evidence
Doing cardio as well as strength training does not reduce muscle growth or maximal strength. It can blunt explosive strength, such as jumping, mainly when both are done in the same session; keep them at least 3 hours apart if that matters to you.
Source 49
Who shouldn't cut caloriesStrong evidence
Don't cut calories if you're pregnant: the NHS says pregnancy isn't the time to go on a diet, so use our pregnancy plan, and if you're breastfeeding, the calories calculator's breastfeeding setting with no cut. Don't cut if you're underweight or losing weight without trying, which needs a GP first, or if you're under 18, unless a professional advises it.
If you take insulin, or diabetes tablets such as gliclazide or glimepiride, eating less and exercising more can bring on low blood sugar (feeling hungry, sweaty, shaky or dizzy), so agree the plan with your diabetes team first. Exercising too much, or spending a lot of time worrying about your weight and body shape, are among the NHS's signs of an eating disorder; it says to see a GP as soon as you can.
Sources 50, 51, 52, 53, 54
Check firstStrong evidence
Answer the 7 questions of the PAR-Q+ (the Physical Activity Readiness Questionnaire for Everyone) before you start. They cover a heart condition or high blood pressure, chest pain, dizziness or fainting, another long-term condition, medicines for one, a bone or joint problem that more activity could make worse, and being told to exercise only under medical supervision. A yes leads to follow-up questions that may send you to your GP or a qualified exercise professional first. With a cold or fever, wait until you're better; if you're pregnant, talk to your midwife or doctor first.
The NHS suggests speaking to a GP first if you haven't exercised for some time, or have a medical condition or concerns. The World Health Organization (WHO) notes that most people without such problems don't need a medical check before light or moderate activity, and the American College of Sports Medicine's (ACSM's) screening looks at how active you are now, any symptoms or known heart, metabolic or kidney disease, and how hard you plan to train.
Hard, all-out effort briefly raises the risk of a heart attack or sudden death from a heart problem in people at risk, mostly those who rarely exercise, and warning signs often come first. If you're over 45 and not used to it, the PAR-Q+ asks you to check with a qualified exercise professional before very hard efforts. Whatever your age, breathe out on the effort rather than holding your breath, which raises blood pressure, as the British Heart Foundation advises.
With ME/CFS (myalgic encephalomyelitis or chronic fatigue syndrome), NICE (the National Institute for Health and Care Excellence) advises against programmes with fixed increases in activity, which is what this plan is.
Sources 55, 35, 15, 56, 57, 58, 59
Stop and get helpStrong evidence
Call 999 in the UK or 911 in the US for chest pain that comes on suddenly and doesn't go away, feels tight or like squeezing or pressure, or spreads to your arms, neck, jaw, stomach or back; chest pain with sweating, feeling sick, light-headedness or breathlessness; severe difficulty breathing; or signs of a stroke, such as one side of the face drooping, weakness in one arm or slurred speech, even if they pass. Don't drive yourself to hospital.
Call 999 or go to A&E for palpitations that don't go away, or that come with chest pain, breathlessness or feeling faint. Call 999 if someone has fainted and isn't breathing, or can't be woken within a minute, and see a GP after any faint. Contact NHS 111 (in the US, your doctor or an urgent care centre) if you're suddenly more short of breath than usual, or have chest pain with feeling sick or a heartbeat that races, skips or flutters.
Dark, red or cola-coloured urine, much less urine than usual, or very painful, weak or swollen muscles after unusually hard training can be rhabdomyolysis, a breakdown of muscle that can harm the kidneys: get medical help the same day.
Severe difficulty breathing means gasping, choking or not being able to get your words out: call 999 for that, or if your lips or skin are turning very pale, blue or grey, or you suddenly feel confused. Call 999, too, if someone faints while exercising. Losing weight much faster than planned, with dizziness or exhaustion, means eating more, and seeing a GP if it carries on (our suggestion).
Sources 60, 61, 62, 63, 64, 65, 66, 67
How to adapt it
Our suggestions, with the evidence where there is some:
- Two strength days: workouts A and B with at least a day between, and three cardio sessions. Recomposition will be slower.
- Four days, with 6 months or more of lifting: the 4-day option in the phases.
- No gym: the home track in the phases, or our 3-day home workout plan.
- Trained and lean: eat at maintenance or cut very little, keep protein at the top of the range and expect it to take months; or run the muscle-building plan at maintenance, then a slow fat-loss block.
- On a GLP-1 weight-loss medicine (glucagon-like peptide-1), such as semaglutide or tirzepatide: the UK guidelines say people taking these especially need to keep up strength training, because both fat and muscle fall. Our weight loss plan's notes cover the rest.
- Sore joints or a higher body weight: the bike or the pool for cardio, and the leg press instead of the trap bar deadlift for a few weeks.
- Missed a week: repeat it. A holiday or illness: keep your protein and walks going, and restart a phase back.
Source 68