Fit for life, on the evidence we actually have.

Start here

You already know the answer: move more, eat well, sleep enough. So why does almost everyone fail at it? Because the advice they get is vague, contradictory, or quietly outdated. This chapter is the whole guide in ninety seconds.

A lot has moved since the first edition in 2017. Where the research has changed the answer, you will find a What changed since 2017 box in the margin of the chapter - short, side by side, no lecture.

The good news is that the corrections almost all run in the same direction: less is required than you were told. Not 10000 steps but around 7000. Not an hour in the gym five times a week but two honest strength sessions. Not a perfect diet but enough protein and mostly real food. The bar is lower than the fitness industry needs you to believe.

The whole guide, condensed

How to read it

Ten chapters, grouped into move, eat, recover, and do. Each one ends with a Do this box: two to four concrete actions, small enough to start today. If you only have ten minutes, read chapter 11 and work backwards from there.

Claims that carry a number also carry a source. The reference numbers link to the source list at the bottom, where you will find the studies behind every figure in this guide. Use the search box in the sidebar to jump to any topic.

Move all day, not just at the gym

A week has 168 hours. You sleep for about 56 of them. Training takes three. What you do with the remaining 109 hours decides more about your health than the three ever will.

Humans were built to walk, carry, climb and squat throughout the day, not to sit still for nine hours and then compensate with one hard session. That is not nostalgia for the stone age, it is simply where the health effect is largest: the difference between moving very little and moving moderately is far bigger than the difference between moderate and a lot.

The 10000-step myth

Ten thousand steps was never a research finding. It came from a Japanese pedometer marketing campaign in the 1960s - the device was called manpo-kei, the ten-thousand-step meter. The number stuck because it is round, not because it is right.

The practical consequence matters more than the number itself. If you currently walk 3000 steps, going to 6000 buys you far more health than an already-active person going from 9000 to 12000. The steepest part of the curve is at the bottom - which is exactly where a discouraging target like 10000 does the most damage.

Sitting: real risk, wrong headline

"Sitting is the new smoking" was always rhetoric. Sitting is genuinely associated with worse health outcomes, but two findings from accelerometer studies reframe the problem entirely.

So sitting is mainly a problem for people who are otherwise inactive. If you walk your 7000 steps and train twice a week, a desk job is not sabotaging you.

Activity snacks and the stair test

Breaking up long sitting bouts does something measurable. In a controlled trial, interrupting sitting every 20 minutes lowered post-meal glucose by around 24 to 30 % and insulin by around 23 %.⁶ The intensity of the break seems to matter less than taking it at all: in a small crossover study, one minute of repeatedly standing up from a chair every 30 minutes worked at least as well as two minutes of treadmill walking.⁷ Meta-analysis confirms the direction across studies, though effect sizes vary.⁸

There is stronger evidence for short bursts of genuinely hard effort woven into ordinary life - taking stairs quickly, walking uphill at pace, carrying shopping. Three to four minutes a day of this kind of activity is associated with substantially lower mortality, and bouts as short as one to two minutes count.⁹

The five movement patterns

Your body does not have a biceps day. It pushes, pulls, rotates, moves through space and changes level. Build your training around those five things and you cover everything a human body is asked to do.

The classic gym machine was designed on a purely mechanical idea: across joint A, muscle B pulls on bone C, so train B in isolation. It is tidy engineering and poor biology. Outside the machine you never use one muscle alone. You produce force, control the movement and stabilise everything else at the same time - and that coordination is precisely what a fixed-path machine removes.

This is not an argument that machines are useless. For adding volume to a single muscle safely, especially when you are new or coming back from injury, they work well. It is an argument about what your programme should be built around. Start from patterns, then add isolation if you want it.

How much training you actually need

Three different goals, three completely different doses. Confusing them is why people either do far too little and wonder why nothing happens, or far too much and quit.

The single most useful thing to understand about training volume is that health, muscle and maximal strength do not need the same amount of work. The dose that buys most of the longevity benefit is remarkably small. The dose that builds visible muscle is larger. They are separate questions and the honest answer to each is different.

Goal one: live longer and better

The current WHO guideline asks adults for 150 to 300 minutes of moderate activity per week, or 75 to 150 minutes of vigorous activity, plus muscle-strengthening work on at least two days a week.¹ The strength component is a requirement, not a bonus - and it is the part most people skip.

For strength specifically, the dose-response curve is startlingly flat. Thirty to sixty minutes of strength training per week is associated with 10 to 20 % lower risk across all-cause mortality, cardiovascular disease and cancer - about 15 % for all-cause mortality alone, with the low point near 40 minutes a week. The curve is J-shaped: beyond about sixty minutes the benefit for mortality does not just stop, it tends to reverse.⁴ Combine strength with cardio and the effect is far larger: around 40 % lower all-cause mortality.

Goal two: build muscle

Here volume genuinely matters. Muscle growth increases with weekly sets, and the returns diminish only mildly - roughly 0.24 % more hypertrophy per additional set around a typical weekly volume of about twelve sets.¹⁰ Ten hard sets per muscle group per week is a sensible floor. Strength, by contrast, plateaus much earlier: past moderate set counts you buy very little extra.

Two findings make this much easier to apply than it sounds. First, load is flexible: anything from 30 to 100 % of your one-rep max builds muscle.¹¹ Second, frequency barely matters for hypertrophy when weekly volume is equal - twice a week is convenient, not magic.¹⁰

Goal three: get maximally strong

Maximal strength is the one goal with a genuinely specific requirement: heavy loads, at or above 80 % of your one-rep max, two to three sets, full range of motion, main lifts placed early in the session, at least twice a week.¹¹ Higher frequency does help here, unlike for hypertrophy.

Getting stronger, week after week

Progress is not complicated, but almost every popular explanation of it is wrong. You do not need a periodisation model, a two-week exercise rotation, or a session that leaves you destroyed. You need the same movements, done a little better, over and over.

Forget supercompensation

The supercompensation curve is the model most of us learned: train, capacity drops, the body overshoots on repair, and you catch the peak 48 to 72 hours later. Elegant, memorable, and no longer how sport science describes adaptation.

The better mental model is fitness minus fatigue: every session raises long-term capacity while adding short-term tiredness, and the two decay at different rates. Useful for thinking. Not reliable enough to convert into a schedule, which is why nobody should sell you one.¹²

What actually drives progress

Four variables carry almost all of the effect. Everything else is detail.

Notably absent from that list: the type of equipment, complex periodisation schemes, and training to absolute failure. The most recent position stand found that going to failure does not consistently change outcomes.¹¹ Meta-analysis does show a small advantage for sets taken closer to failure - an effect size of about 0.19, right at the edge of significance - so it is a mild preference, not a requirement.¹³ Leaving two to three repetitions in reserve costs you very little and saves a great deal of fatigue.

Vary systematically, not randomly

Variation is worth having - a muscle is not stimulated evenly by every exercise, and different angles and joint positions load different regions of it. Choosing exercises that between them cover a muscle from several directions is how you avoid building a strong middle and a weak edge. Systematic variation of this kind appears to improve regional growth and maximal strength.¹⁴

What does not work is variation for its own sake. "Muscle confusion" is a marketing idea, and excessive random rotation can hold your progress back rather than accelerate it.¹⁴ When a fixed exercise selection was compared against randomly chosen exercises at equal volume, the varied group gained no more; its one clear advantage was higher intrinsic motivation - which is not nothing, but it is not a training effect.¹⁴

Mobility: you probably do not need a separate routine

Mobility first, then strength, then coordination - it is a tidy hierarchy, and there is no evidence behind it. Range of motion is not a prerequisite for developing strength, endurance or health.

What the evidence does show is that strength training through a full range of motion improves flexibility just as well as stretching does - a meta-analysis of eleven studies found no significant difference between the two.¹⁵ Train through full range and you get the mobility for free, plus the strength.

• Static stretching immediately before lifting reduces performance by around 3.7 % on average - but mainly when held longer than 60 seconds per muscle and not followed by dynamic work.¹⁶ Short holds inside a proper warm-up are fine.
• Static stretching shows no clear effect on injury rates in either direction - the same review that documents the performance cost still recommends keeping short static stretching inside a full warm-up followed by dynamic work.¹⁶ The intervention with solid evidence for injury prevention is strength training.
• Range gains from stretching come largely from increased stretch tolerance, not from permanently lengthened muscle.¹⁵
• If a specific position is limited - deep squat, overhead reach - targeted mobility work is worth doing. As a general daily requirement, it is not.

Your natural potential

Everyone wants the same number: how much muscle can I build without drugs? The honest answer is that nobody can calculate it for you. What the data can tell you is where you stand today and what a realistic year looks like - and that turns out to be more useful anyway.

Three models circulate widely for this. All three are worth understanding, because all three are quoted as fact and none of them survives close inspection.

Where you stand: the FFMI

Fat-free mass index is your lean body mass divided by your height squared. It was originally designed to detect malnutrition, not to police doping, but as a descriptive number it is useful: it tells you how much lean tissue you carry relative to your frame, which body weight alone cannot.

For context: the median FFMI of men aged 18 to 34 in the general population is about 18.9, and for women about 15.4.⁵¹ Anything in the twenties for a man is genuinely well-trained. The band above 25 is rare - but rare is not the same as impossible, and the height adjustment above is included only because you will see it quoted elsewhere. It has never been reproduced; one later dataset found the correction runs in the opposite direction.⁵⁰

What a realistic year looks like

Across 111 studies and 1927 men, whole-body strength training added about 1.5 kg of muscle over eight to sixteen weeks - with a range across studies from nothing at all to 7.2 kg.⁵² Extrapolate that carefully, allow for the fact that the rate falls rather than holds, and a genuinely untrained young man who trains and eats well can expect roughly 4 to 7 kg of lean mass in his first year. Exceptional responders reach nine or ten. Almost nobody reaches eighteen.

For perspective on the far end: American college football players - selected for size, professionally coached and fed for four years - gain around 4 kg of lean mass across their entire college career.⁵³ That is what a highly optimised environment produces once the beginner window closes.

How different are people, really?

Very. In the largest study of its kind, 585 people did the same twelve-week arm programme and the change in muscle cross-section ranged from minus 2 % to plus 59 %.⁵⁵ Training volume did not explain the difference.

Two caveats keep that from being depressing. First, most people clustered in the middle - 232 of the 585 landed between plus 15 and plus 25 %, and true extreme non-responders were well under 1 %. Second, and more importantly, a good part of that spread is measurement noise rather than a fixed personal trait. When the same people repeat an intervention, the apparent differences shrink considerably, and someone who responds poorly to one dose often responds well to another.

Energy and protein

Two numbers run your nutrition: how much energy you take in, and how much protein comes with it. Get those roughly right and almost everything else is preference.

Estimating your energy needs

Start with resting metabolic rate. The most accurate of the common formulas is Mifflin-St Jeor, which the 2017 edition of this guide did not use - it used Harris-Benedict, which systematically overestimates and performs worse in direct comparison.¹⁷

Meal frequency does almost nothing

Few nutrition beliefs are as durable as the idea that eating on a schedule keeps blood sugar level and therefore keeps fat off. It does not survive contact with the evidence.

Protein: the one number worth remembering

For building muscle, around 1.6 g of protein per kg of body weight per day is the best available orientation point.²⁰ Treat it as a soft target inside a sensible range of about 1.4 to 2.0, not as a threshold you fail by missing.

Plant-based, vegetarian, omnivore - all three work

This is the chapter people expect to be a compromise. It is not. When protein intake is matched, the evidence shows no meaningful difference in muscle or strength between people who eat animal products and people who do not.

The most direct test is also the cleanest. Nineteen vegans and nineteen omnivores trained for twelve weeks, both groups brought to 1.6 g of protein per kg of body weight. The result: no difference in muscle cross-sectional area and no difference in strength.²³

That is not one lucky study. A 2026 review of long-term randomised trials of protein supplementation - eighteen trials, 1893 participants, six months or longer - found no significant differences between plant and animal protein in lean mass, fat mass, strength, physical performance or cardiometabolic markers.²⁴ Worth knowing when you weigh it: that review tested supplements rather than whole diets, and most of its authors work for a nutrition company.

Where the differences are real

Presenting only the parity findings would be cherry-picking. Three genuine caveats:

• Acute measurements slightly favour animal protein. In short-term muscle protein synthesis studies, animal sources come out modestly ahead. The gap is small and it does not translate into differences in hypertrophy over months.²⁶
• Not all plant proteins are equal. Animal protein does beat non-soy plant proteins such as rice, oat, chia and potato for muscle mass. Soy versus dairy shows no difference, and no source shows a difference for strength.²⁷
• Protein density is the real obstacle. Not quality - volume. Whole plant foods carry less protein per calorie, so hitting 1.6 g / kg from lentils and oats alone means eating a lot. This, not amino acid profiles, is why plant-based athletes fall short.

Protein quality, honestly

DIAAS scores how well a protein is digested and how complete its amino acid profile is. Values above 100 are excellent, 75 to 99 is good, below 75 means the source is limited by one amino acid - usually lysine in grains and sulphur amino acids in legumes. All values below use the same reference pattern, so they are comparable with each other.²⁷

Read the table sideways rather than top to bottom. Wheat is limited by lysine; legumes are rich in it. Legumes are limited by sulphur amino acids; grains supply them. Eat both across the day and the limitation disappears - and the old advice to combine them within the same meal has been retired.²⁵

Nutrients worth planning for

Some of these are specific to plant-based eating. Several are not. The right-hand column tells you who should pay attention.

Food quality without the dogma

"Eat real food" is good advice. The reasons usually given for it are mostly wrong, and the version that turns into a purity test helps nobody.

The strongest evidence for whole foods is not about chemicals or additives. It is about how easy a food makes it to eat too much of it. In a tightly controlled trial where people lived in a research facility and ate as much as they wanted, an ultra-processed menu led to 508 kcal more per day than an unprocessed one matched for sugar, fibre and macronutrients - and participants gained 0.9 kg in two weeks on the first and lost 0.9 kg on the second.³¹

A larger and longer trial published in 2025 tested both menus built to the UK national dietary guidelines over eight weeks each. Both produced weight loss. The minimally processed one produced about twice as much: 2.06 % versus 1.05 % of body weight.³² Real, worth having, and considerably more modest than the headlines suggest.

Why it happens

Nothing mysterious. Highly processed food tends to be energy dense, soft, quick to chew and engineered to taste good, so you take in more calories per minute of eating and feel less full afterwards. Change those properties and much of the effect goes with them.

A shopping list that does the work for you

Deciding well at the supermarket once a week beats deciding well at home twenty times. Keep these in stock and a decent meal is never more than fifteen minutes away.

Sleep and stress

Training is the stimulus. Recovery is where the adaptation happens. And of everything in this guide, sleep has the largest effect for the least effort.

Sleep

The consensus recommendation for adults is seven hours or more, regularly.³³ The effect of falling short is not subtle: across 69 publications and 227 outcomes, acute sleep loss reduced physical performance by about 7.6 %, and being woken early hurt more than going to bed late.³⁴

It also changes what you lose when dieting. In a controlled study where the calorie deficit was identical, restricting sleep to 5.5 hours instead of 8.5 kept total weight loss the same but shifted its composition sharply: fat loss fell from 1.4 to 0.6 kg while lean-mass loss rose from 1.5 to 2.4 kg.³⁵ The sample was ten people and the condition extreme, so read the direction rather than the exact numbers - but the direction is well supported.

The part of the light story that does hold up is about quantity, not colour. Melatonin is already suppressed at roughly 25 lux - ordinary room lighting - and individual sensitivity spans a roughly fiftyfold range between people, from about 6 to 350 lux.³⁹ So dim the room, cut screen time rather than screen colour, and get bright light in the morning.

Stress and cortisol

Stress genuinely makes it harder to train consistently and eat the way you intended. The mechanism is just not the one usually described.

That is good news, because behaviour is visible and adjustable in a way that hormones are not. And the techniques below have something the old advice did not: they were tested, they have a dose, and you can start any of them this evening.

What actually lowers stress

The part no technique covers

Much of what we call stress is not the situation itself but the running commentary about it - the rehearsal of a conversation that has not happened, the replay of one that has. Every method in this chapter works, in the end, by interrupting that commentary for a few minutes: a muscle you are tensing, a breath you are counting, a body you are lying in. The technique is a door. What you are actually practising is being here rather than somewhere else.

That also explains something the research keeps finding: the specific method matters far less than people expect. What all of them share is a few minutes in which you stop arguing with the present moment. Training does it. So does a walk without headphones, or cooking something properly, or the last ten seconds of a set when there is room for nothing else in your head.

Which brings us back to where this guide started. You do not need to be perfect at any of this. You need to move most days, eat enough good food, sleep on a schedule, and give yourself a few honest minutes of quiet. Everything else is refinement.

Your plan

Everything above condenses into eight questions and one weekly template. Answer the questions honestly, pick the template that matches the days you really have, and start this week.

The eight questions

1. Do you move enough during the day?

   Not in the gym - during the day. Cycling to work, walking after dinner, taking the stairs. Look at your seven-day average and add 2000 steps to it, whatever it says.

2. Do you train strength at least twice a week?

   Thirty to sixty minutes a week in total is enough for most of the health effect. Cover all five movement patterns across the week, and do not skip rotation.

3. Are you getting progressively better at something?

   Same exercises, a little more each week - more reps, more load, more range. If you cannot say what improved this month, you are exercising rather than training.

4. Do you hit your protein target?

   Body weight in kg × 1.6. This applies whether you eat meat or not. If you fall short, it is almost always breakfast.

5. Do you know roughly what you eat?

   Not forever - four or five days is enough to calibrate your intuition. Estimate your energy needs, then let your weekly average weight correct the estimate.

6. Do you sleep seven hours, on a schedule?

   The consistent wake-up time matters as much as the total. This is the highest-value change available to most people, and it is free.

7. Do you get real breaks?

   Every 90 minutes of concentrated work, take five. Every 30 minutes of sitting, stand up for one. Recovery is not what happens after training, it is what happens all day.

8. Do you enjoy any of this?

   The most important question on the list. A plan you dislike works until roughly week five. Pick training you look forward to and food you would eat anyway.

Three weekly templates

Choose by how many days you can genuinely commit to, not by how many you would like to. Each session covers several movement patterns and takes 30 to 45 minutes.

What to track

Four things, all cheap to measure. Anything beyond this is a hobby, not a requirement.

Sources

Every number in this guide comes from one of the following. Where the evidence is weak or contested, we said so in the text rather than hiding it here.

1. Bull FC, Al-Ansari SS, Biddle S, et al. (2020). World Health Organization 2020 guidelines on physical activity and sedentary behaviour. Br J Sports Med 54(24):1451-1462. doi:10.1136/bjsports-2020-102955
2. Ding D, Nguyen B, Nau T, et al. (2025). Daily steps and health outcomes in adults: a systematic review and dose-response meta-analysis. Lancet Public Health 10(8):e668-e681. doi:10.1016/S2468-2667(25)00164-1 · Erratum: 10(9):e731.
3. Paluch AE, Bajpai S, Bassett DR, et al. (2022). Daily steps and all-cause mortality: a meta-analysis of 15 international cohorts. Lancet Public Health 7(3):e219-e228. · Stens NA, Bakker EA, Mañas A, et al. (2023). Relationship of daily step counts to all-cause mortality and cardiovascular events. J Am Coll Cardiol 82(15):1483-1494.
4. Momma H, Kawakami R, Honda T, Sawada SS (2022). Muscle-strengthening activities are associated with lower risk and mortality in major non-communicable diseases: a systematic review and meta-analysis of cohort studies. Br J Sports Med 56(13):755-763. doi:10.1136/bjsports-2021-105061
5. Ekelund U, Tarp J, Steene-Johannessen J, et al. (2019). Dose-response associations between accelerometry measured physical activity and sedentary time and all cause mortality: systematic review and harmonised meta-analysis. BMJ 366:l4570. doi:10.1136/bmj.l4570 · Ekelund U, Tarp J, Fagerland MW, et al. (2020). Br J Sports Med 54(24):1499-1506.
6. Dunstan DW, Kingwell BA, Larsen R, et al. (2012). Breaking up prolonged sitting reduces postprandial glucose and insulin responses. Diabetes Care 35(5):976-983. doi:10.2337/dc11-1931
7. Gillen JB, Estafanos S, Williamson E, et al. (2021). Interrupting prolonged sitting with repeated chair stands or short walks reduces postprandial insulinemia in healthy adults. J Appl Physiol 130(1):104-113. doi:10.1152/japplphysiol.00796.2020
8. Loh R, Stamatakis E, Folkerts D, Allgrove JE, Moir HJ (2020). Effects of interrupting prolonged sitting with physical activity breaks on blood glucose, insulin and triacylglycerol measures: a systematic review and meta-analysis. Sports Med 50:295-330. doi:10.1007/s40279-019-01183-w
9. Stamatakis E, Ahmadi MN, Gill JMR, et al. (2022). Association of wearable device-measured vigorous intermittent lifestyle physical activity with mortality. Nat Med 28:2521-2529. doi:10.1038/s41591-022-02100-x
10. Pelland JC, Remmert JF, Robinson ZP, Hinson SR, Zourdos MC (2026). The resistance training dose response: meta-regressions exploring the effects of weekly volume and frequency on muscle hypertrophy and strength gains. Sports Med 56(2):481-505. doi:10.1007/s40279-025-02344-w
11. American College of Sports Medicine Position Stand. Currier BS, D’Souza AC, Fiatarone Singh MA, et al. (2026). Resistance training prescription for muscle function, hypertrophy, and physical performance in healthy adults: an overview of reviews. Med Sci Sports Exerc 58(4):851-872. doi:10.1249/MSS.0000000000003897
12. Kiely J (2018). Periodization theory: confronting an inconvenient truth. Sports Med 48(4):753-764. doi:10.1007/s40279-017-0823-y
13. Refalo MC, Helms ER, Trexler ET, Hamilton DL, Fyfe JJ (2023). Influence of resistance training proximity-to-failure on skeletal muscle hypertrophy: a systematic review with meta-analysis. Sports Med 53(3):649-665. doi:10.1007/s40279-022-01784-y
14. Baz-Valle E, Schoenfeld BJ, Torres-Unda J, Santos-Concejero J, Balsalobre-Fernández C (2019). The effects of exercise variation in muscle thickness, maximal strength and motivation in resistance trained men. PLoS ONE 14(12):e0226989. · Kassiano W, Nunes JP, Costa B, et al. (2022). Does varying resistance exercises promote superior muscle hypertrophy and strength gains? A systematic review. J Strength Cond Res 36(6):1753-1762.
15. Afonso J, Ramirez-Campillo R, Moscão J, et al. (2021). Strength training versus stretching for improving range of motion: a systematic review and meta-analysis. Healthcare 9(4):427. doi:10.3390/healthcare9040427
16. Behm DG, Blazevich AJ, Kay AD, McHugh M (2016). Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review. Appl Physiol Nutr Metab 41(1):1-11. doi:10.1139/apnm-2015-0235
17. Frankenfield D, Roth-Yousey L, Compher C (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. J Am Diet Assoc 105(5):775-789. · Mifflin MD, St Jeor ST, Hill LA, et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 51(2):241-247.
18. Pontzer H, Yamada Y, Sagayama H, et al. (2021). Daily energy expenditure through the human life course. Science 373(6556):808-812. doi:10.1126/science.abe5017
19. Schoenfeld BJ, Aragon AA, Krieger JW (2015). Effects of meal frequency on weight loss and body composition: a meta-analysis. Nutr Rev 73(2):69-82. · Kahleova H, Belinova L, Malinska H, et al. (2014). Eating two larger meals a day is more effective than six smaller meals in a reduced-energy regimen for patients with type 2 diabetes. Diabetologia 57:1552-1560.
20. Morton RW, Murphy KT, McKellar SR, et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength. Br J Sports Med 52(6):376-384. Breakpoint 1.62 g/kg (95 % CI 1.03-2.20). doi:10.1136/bjsports-2017-097608
21. Refalo MC, Trexler ET, Helms ER (2025). Effect of dietary protein on fat-free mass in energy restricted, resistance-trained individuals: an updated systematic review with meta-regression. Strength Cond J, ahead of print. doi:10.1519/SSC.0000000000000888
22. Trommelen J, van Lieshout GAA, Nyakayiru J, et al. (2023). The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans. Cell Rep Med 4(12):101324. doi:10.1016/j.xcrm.2023.101324
23. Hevia-Larraín V, Gualano B, Longobardi I, et al. (2021). High-protein plant-based diet versus a protein-matched omnivorous diet to support resistance training adaptations. Sports Med 51(6):1317-1330. doi:10.1007/s40279-021-01434-9
24. Yimam MA, Roberts J, O’Callaghan A, et al. (2026). Long-term effects of plant vs. animal protein supplementation on body composition, muscle strength, physical performance, and cardiometabolic risk factors in adults: a systematic review and meta-analysis of randomized controlled trials. Front Nutr 13:1813846. doi:10.3389/fnut.2026.1813846
25. König D, Carlsohn A, Braun H, et al. (2020). Proteinzufuhr im Sport - Position der Arbeitsgruppe Sporternährung der Deutschen Gesellschaft für Ernährung. Ernährungs Umschau 67(7):M406-M413. doi:10.4455/eu.2020.039
26. Mendes BR, Correia JM, dos Santos IR, Schoenfeld BJ, Swinton PA, Mendonça GV (2026). Effects of plant- vs animal-based proteins on muscle protein synthesis: a systematic review with meta-analysis. J Acad Nutr Diet, online ahead of print.
27. Reid-McCann RJ, Brennan SF, Ward NA, Logan D, McKinley MC, McEvoy CT (2025). Effect of dietary protein source on muscle mass and strength in adults. Nutr Rev 83(7):e1581-e1603. doi:10.1093/nutrit/nuae200 · DIAAS values: Mathai JK, Liu Y, Stein HH (2017). Br J Nutr 117(4):490-499 · Han F, Moughan PJ, Li J, Pang S (2020). Nutrients 12(12):3831.
28. Kaviani M, Shaw K, Chilibeck PD (2020). Benefits of creatine supplementation for vegetarians compared to omnivorous athletes: a systematic review. Int J Environ Res Public Health 17(9):3041. doi:10.3390/ijerph17093041
29. Klug A, Barbaresko J, Alexy U, et al. (2024). Neubewertung der DGE-Position zu veganer Ernährung. Ernährungs Umschau 71(7):M382-M386. · Raj S, Guest NS, Landry MJ, et al. (2025). Vegetarian dietary patterns for adults: a position paper of the Academy of Nutrition and Dietetics. J Acad Nutr Diet. doi:10.1016/j.jand.2025.02.002
30. West S, Monteyne AJ, Whelehan G, et al. (2023). Nutritional considerations for the vegan athlete. Adv Nutr 14(4):774-795.
31. Hall KD, Ayuketah A, Brychta R, et al. (2019). Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metab 30(1):67-77.e3. doi:10.1016/j.cmet.2019.05.008
32. Dicken SJ, Qamar S, Batterham RL, Hall KD, et al. (2025). Ultraprocessed or minimally processed diets following healthy dietary guidelines on weight and cardiometabolic health: a randomized, crossover trial. Nat Med 31:3297-3308. doi:10.1038/s41591-025-03842-0
33. Watson NF, Badr MS, Belenky G, et al. (2015). Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep 38(6):843-844.
34. Craven J, McCartney D, Desbrow B, et al. (2022). Effects of acute sleep loss on physical performance: a systematic and meta-analytical review. Sports Med 52:2669-2690. doi:10.1007/s40279-022-01706-y
35. Nedeltcheva AV, Kilkus JM, Imperial J, Schoeller DA, Penev PD (2010). Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med 153(7):435-441. n = 10. doi:10.7326/0003-4819-153-7-201010050-00006
36. Singh S, Keller PR, Busija L, et al. (2023). Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults. Cochrane Database Syst Rev 8:CD013244. doi:10.1002/14651858.CD013244.pub2
37. Duraccio KM, Zaugg KK, Blackburn RC, Jensen CD (2021). Does iPhone night shift mitigate negative effects of smartphone use on sleep outcomes in emerging adults? Sleep Health 7(4):478-484. doi:10.1016/j.sleh.2021.03.005
38. Baniassadi A, Manor B, Yu W, Travison T, Lipsitz L (2023). Nighttime ambient temperature and sleep in community-dwelling older adults. Sci Total Environ 899:165623. · Okamoto-Mizuno K, Mizuno K (2012). Effects of thermal environment on sleep and circadian rhythm. J Physiol Anthropol 31:14.
39. Phillips AJK, Vidafar P, Burns AC, et al. (2019). High sensitivity and interindividual variability in the response of the human circadian system to evening light. PNAS 116(24):12019-12024. ED50 = 24.6 lux, individual range 6-350 lux. doi:10.1073/pnas.1901824116
40. van der Valk ES, Abawi O, Mohseni M, et al. (2022). Cross-sectional relation of long-term glucocorticoids in hair with anthropometric measurements and their possible determinants: a systematic review and meta-analysis. Obes Rev 23(3):e13376. doi:10.1111/obr.13376
41. Stubbs B, Vancampfort D, Rosenbaum S, et al. (2017). An examination of the anxiolytic effects of exercise for people with anxiety and stress-related disorders: a meta-analysis. Psychiatry Res 249:102-108. doi:10.1016/j.psychres.2016.12.020 · Aylett E, Small N, Bower P (2018). BMC Health Serv Res 18:559.
42. Donato KO, Falcão L, Nishizima A, et al. (2026). Progressive muscle relaxation technique improves sleep quality and mental health: a systematic review and meta-analysis of randomized controlled trials. J Psychosom Res 203:112563. doi:10.1016/j.jpsychores.2026.112563 · Blood pressure: Rainforth MV, Schneider RH, Nidich SI, et al. (2007). Curr Hypertens Rep 9(6):520-528.
43. Manzoni GM, Pagnini F, Castelnuovo G, Molinari E (2008). Relaxation training for anxiety: a ten-years systematic review with meta-analysis. BMC Psychiatry 8:41. doi:10.1186/1471-244X-8-41 · Short form: Carlson CR, Hoyle RH (1993). J Consult Clin Psychol 61(6):1059-1067.
44. Laborde S, Allen MS, Borges U, et al. (2022). Effects of voluntary slow breathing on heart rate and heart rate variability: a systematic review and meta-analysis. Neurosci Biobehav Rev 138:104711. doi:10.1016/j.neubiorev.2022.104711 · Blood pressure: Cheng S, Chen Y, Yu M, et al. (2026). Clin Cardiol 49(3):e70279.
45. Fincham GW, Strauss C, Cavanagh K (2023). Effect of coherent breathing on mental health and wellbeing: a randomised placebo-controlled trial. Sci Rep 13:22141. doi:10.1038/s41598-023-49279-8
46. Goyal M, Singh S, Sibinga EMS, et al. (2014). Meditation programs for psychological stress and well-being: a systematic review and meta-analysis. JAMA Intern Med 174(3):357-368. doi:10.1001/jamainternmed.2013.13018 · Khoury B, Sharma M, Rush SE, Fournier C (2015). J Psychosom Res 78(6):519-528.
47. Goldberg SB, Lam SU, Britton WB, Davidson RJ (2022). Prevalence of meditation-related adverse effects in a population-based sample in the United States. Psychother Res 32(3):291-305. doi:10.1080/10503307.2021.1933646 · Farias M, Maraldi E, Wallenkampf KC, Lucchetti G (2020). Acta Psychiatr Scand 142(5):374-393.
48. Balban MY, Neri E, Kogon MM, et al. (2023). Brief structured respiration practices enhance mood and reduce physiological arousal. Cell Rep Med 4(1):100895. doi:10.1016/j.xcrm.2022.100895
49. Kouri EM, Pope HG Jr, Katz DL, Oliva P (1995). Fat-free mass index in users and nonusers of anabolic-androgenic steroids. Clin J Sport Med 5(4):223-228. doi:10.1097/00042752-199510000-00003 · Origin of the index: VanItallie TB, Yang MU, Heymsfield SB, et al. (1990). Am J Clin Nutr 52(6):953-959.
50. Trexler ET, Smith-Ryan AE, Blue MNM, et al. (2017). Fat-free mass index in NCAA Division I and II collegiate American football players. J Strength Cond Res 31(10):2719-2727. doi:10.1519/JSC.0000000000001737 · Fields JB, Jones MT, Kuhlman NM, et al. (2024). Int J Exerc Sci 17(4):129-139.
51. Schutz Y, Kyle UUG, Pichard C (2002). Fat-free mass index and fat mass index percentiles in Caucasians aged 18-98 y. Int J Obes Relat Metab Disord 26(7):953-960.
52. Benito PJ, Cupeiro R, Ramos-Campo DJ, Alcaraz PE, Rubio-Arias JÁ (2020). A systematic review with meta-analysis of the effect of resistance training on whole-body muscle growth in healthy adult males. Int J Environ Res Public Health 17(4):1285. doi:10.3390/ijerph17041285
53. Trexler ET, Smith-Ryan AE, Mann JB, Ivey PA, Hirsch KR, Mock MG (2017). Longitudinal body composition changes in NCAA Division I college football players. J Strength Cond Res 31(1):1-8.
54. Refalo MC, Nuckols G, Galpin AJ, Gallagher IJ, Hamilton DL, Fyfe JJ (2025). Sex differences in absolute and relative changes in muscle size following resistance training in healthy adults: a systematic review with Bayesian meta-analysis. PeerJ 13:e19042. doi:10.7717/peerj.19042 · Roberts BM, Nuckols G, Krieger JW (2020). J Strength Cond Res 34(5):1448-1460.
55. Hubal MJ, Gordish-Dressman H, Thompson PD, et al. (2005). Variability in muscle size and strength gain after unilateral resistance training. Med Sci Sports Exerc 37(6):964-972. doi:10.1249/01.mss.0000170469.90461.5f · On response heterogeneity as partly measurement noise: Räntilä A et al. (2025). Eur J Sport Sci. doi:10.1002/ejsc.70095