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Andrew Valentine
Andrew Valentine

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A nutrition kit from Andrew Valentine

Run Your Own Nutrition

Everything you need to set, track, and adjust your own eating for a cut, a bulk, a recomp, or maintenance. The goal is for you to understand the system well enough that you never need someone to hand you a meal plan again.

The fast path

about 30 minutes, then start
  1. Read the Primer.
  2. Read the playbook for your goal.
  3. Run the calculator and start eating to it tomorrow.

The full kit

about an hour
  1. Everything in the fast path.
  2. My Rules, the AI guide, and the red flags page.
  3. Use the check-in log every day, and review it once a week.

Every claim that matters has a small number next to it that links to the study behind it. You don't have to take my word for anything. Check it.

Part one · about 20 minutes

The Primer

Nutrition feels complicated because it's usually taught as a list of foods and rules. Underneath, it's a small system with a handful of variables. Once you can see the variables and how they connect, most of the noise goes away. This primer walks through that system in the order it matters.

01Energy balance decides your weight

Your body weight moves according to the gap between the energy you eat and the energy you burn. Eat more than you burn and the extra gets stored. Eat less and the body pulls from storage to cover the gap. No diet escapes this. Keto, fasting, vegan, and carnivore all work, when they work, by changing that gap.

The energy you burn in a day is your total daily energy expenditure, or TDEE. It has four parts:

PartShareWhat it is
Resting metabolism~60–70%Keeping you alive at rest: organs, brain, body temperature. Scales mostly with body size and lean mass.
Thermic effect of food~10%The cost of digesting what you eat. Protein costs the most to digest, fat the least.
Exercise~5–10%Your training sessions. Usually smaller than people think.
NEATvaries a lotNon-exercise activity: walking, standing, fidgeting, chores. Can differ by several hundred calories a day between people, or for the same person across weeks.

NEAT is the part to watch. In a classic overfeeding study, people were all given the same extra 1,000 calories a day. How much fat each person gained was explained mostly by how much their NEAT rose to burn off the extra.1 The same thing happens in reverse when you diet. You move a little less, pace less, and take the elevator, usually without noticing. That's a big part of why progress slows, and it's why a daily step target shows up later in this kit.

Estimates are starting guesses

Online calculators estimate TDEE from your height, weight, age, sex, and activity level. For any one person they can easily be off by 10% or more, which can be 200 to 300 calories a day. So treat the calculator number as a first guess. Your real maintenance is the intake that keeps your weight trend flat over a few weeks of honest tracking. You find it by eating a set amount, watching what the scale trend does, and correcting.

Does your metabolism "adapt" to dieting?

Yes, but less than people claim. As you lose weight, you burn less, mainly because there's less of you to run and because NEAT drops. On top of that there is a small extra slowdown, called adaptive thermogenesis. In normal dieting it amounts to tens to low hundreds of calories a day, and it fades once you return to maintenance. The dramatic numbers you may have seen come from contestants on a TV weight-loss show who lost enormous amounts of weight very fast.2 That's an extreme case, not what happens to someone losing 5 kg over three months.

The takeaway

To lose fat, you need a deficit. To gain muscle efficiently, a small surplus helps. Everything else in this kit is about setting that gap to the right size, making it easy to sustain, and making sure the weight you change is the kind you want.

02Protein decides what the weight is made of

Calories decide how much your weight changes. Protein, together with your training, decides what changes: fat or muscle. It's the one macronutrient that deserves a precise daily target.

Protein supplies the amino acids your body uses to repair and build muscle after training. It also keeps you fuller than carbs or fat, calorie for calorie, and it takes the most energy to digest. That makes it the most useful macro during a cut and a necessary one in every other phase.

How much

A large meta-analysis of 49 trials found that the muscle-building benefit of extra protein levels off at around 1.6 g per kg of bodyweight per day. Some people kept benefiting up to about 2.2 g/kg.4 When you're dieting, the risk of losing muscle goes up, and the evidence supports going higher, especially if you're lean.5

Situationg/kg/dayg/lb/day
Maintenance or bulk1.6–2.00.7–0.9
Cut or recomp2.0–2.40.9–1.1
Carrying a lot of body fat (BMI over ~30)Use your goal weight in place of your current weight

If you want one number to remember, use 1 gram per pound of bodyweight. It's a little more than most people strictly need, and a little extra protein doesn't hurt you. That makes it a safe, simple default.

How to spread it

Total daily protein matters far more than timing. That said, eating it across three to five meals, with a solid serving each time (about 0.4 g/kg, or 30–50 g for most people), is an easy and sensible default.7 You may have heard that your body can only "use" 25–30 g of protein per meal. That's wrong. A 2023 study found that a 100 g serving produced a bigger and longer-lasting muscle-building response than 25 g.8 Larger, less frequent protein meals work fine. That matters if you eat in a fasting window.

Does the source matter?

Not much, once you're eating enough. Animal proteins (meat, fish, eggs, dairy, whey) are dense in protein and high in leucine, the amino acid most tied to muscle building. Plant proteins work too. Aim toward the higher end of the range and mix sources such as soy, legumes, grains, and pea or soy powder so you cover all the amino acids you need. There's a protein-source table in the cheat sheet.

03Carbs and fat fill the rest

Once calories and protein are set, the rest of your calories come from carbs and fat. How you split them matters much less than the internet suggests. Researchers have tested this in metabolic wards, where every bite is controlled. When calories are matched, cutting carbs doesn't produce meaningfully more fat loss than cutting fat.9 Low-carb diets can feel faster at first because you lose stored glycogen and the water that comes with it. That's water, not fat.

Fat: keep a floor

Fat is needed for hormone production, absorbing vitamins A, D, E, and K, and cell membranes. Very low-fat diets modestly reduce testosterone in men.10 Keep fat at or above about 0.6 g per kg of bodyweight (roughly 20–25% of your calories) in every phase. Get most of it from whole foods like eggs, fish, meat, dairy, nuts, olive oil, and avocado.

Carbs: fuel for hard training

Carbs are stored in your muscles as glycogen, which fuels high-effort work: heavy sets, sprints, rounds of grappling, practices. People who train hard and often usually perform better and recover better with more carbs. People who train lightly can do fine with fewer. Once protein and your fat floor are set, carbs get whatever calories are left. You can shift that balance toward fat or toward carbs based on what you enjoy and how you perform.

The takeaway

Set calories. Set protein. Keep fat above its floor. Then pick the carb/fat balance you'll actually stick to. For fat loss and muscle gain, the best split is mostly the one you can repeat.

04Food quality: fiber, micronutrients, water, salt

Energy balance decides your weight. Food quality decides how easy it is to hold that balance, and how healthy you are while you do it.

The clearest evidence comes from a tightly controlled study. People got two diets matched for calories on the plate, sugar, fat, fiber, and salt: one ultra-processed, one minimally processed. They could eat as much as they wanted. On the ultra-processed diet they ate about 500 calories more per day and gained weight. On the minimally processed diet they lost weight.14 Processed food is easier to overeat. It's softer, faster to eat, more calorie-dense, and less filling. Whole foods do some of your portion control for you.

Fiber

Aim for about 14 g per 1,000 calories you eat, which works out to roughly 25–38 g a day for most adults. Fiber keeps you full, keeps digestion regular, and feeds the bacteria in your gut. Vegetables, fruit, beans, lentils, oats, potatoes with the skin, and whole grains are the easy sources. If you're far below this now, raise it over a couple of weeks and drink more water while you do, or your gut will let you know.

Micronutrients

Vitamins and minerals come along for free when you eat a range of whole foods: several colors of plants, some fruit, some dairy or fortified alternatives, and fish now and then. Commonly low for many people are vitamin D (especially with little sun), magnesium, potassium, and omega-3 fats (if you rarely eat fatty fish). Fix these with food first. A blood test can tell you if vitamin D needs a supplement.

Water and electrolytes

You don't need a gallon a day by rule. Drink enough that your urine is pale yellow and you aren't walking around thirsty. If you sweat heavily (hot gyms, long practices, two-a-days), replace sodium as well as water. Salty food or an electrolyte drink with real sodium does the job.

Salt and the scale

A salty meal can put 0.5–1.5 kg of water on the scale overnight. That's water, not fat, and it's gone in a day or two. Sodium isn't something to fear for healthy, active people. It's something to understand, so a salty restaurant dinner doesn't make you think your diet failed.

05How fast you should change

Your body can only build muscle so fast, and it can only lose fat so fast without also giving up muscle. The rates below come from studies on lifters and athletes. Think of them as speed limits.

GoalWeekly changeNotes
Cut−0.5 to −1.0% BWLeaner people should go slower. Athletes losing about 0.7% a week kept more muscle and strength than athletes losing about 1.4% a week.11
Bulk (newer lifter)+0.25 to +0.5% BWRoughly 1–2% of bodyweight a month.
Bulk (experienced)+0.1 to +0.25% BWIn trained lifters, a larger surplus added more fat without clearly adding more muscle.12
Recomp~0Scale stays about flat; waist shrinks and lifts go up.
Maintenance~0 (±1%/month)Hold a weight range, not a single number.

For an 80 kg (176 lb) person, a 0.75% weekly cut rate means losing about 0.6 kg (1.3 lb) a week. A 0.25% bulk rate means gaining about 0.2 kg (0.45 lb) a week, which is less than a single meal's worth of scale noise. That's why bulking has to be judged over months.

Recomp: who it works for

Losing fat and gaining muscle at the same time is real. It works best for beginners, people coming back after time off, people carrying more body fat, and people whose protein was low before. For a lean, experienced lifter it's slow enough that it's usually better to alternate focused cuts and bulks.13

06Measuring: what to track and how

You can't adjust what you don't measure. People estimating their own intake routinely underreport it, sometimes by a lot. In one well-known study, people who described themselves as "diet-resistant" were eating about 47% more than they reported.3 They weren't lying. Eyeballing food just isn't accurate. Tracking fixes that.

The inputs: food

Use a food scale and a tracking app with verified entries (MacroFactor, Cronometer, MyFitnessPal with verified foods, or similar). Weigh foods raw when you can, and log everything, including cooking oil, sauces, and drinks. Most people only need to hit two numbers: calories within about ±100 and protein at or above target. Carbs and fat can float as long as fat stays above its floor.

The outputs: your body

MeasureHow oftenHow
BodyweightDailyRight after waking, after the bathroom, before food or water. Only look at the 7-day average.
WaistWeeklyTape at the navel, relaxed, same day each week.
PhotosEvery 2–4 weeksSame light, same spot, same time of day. Front, side, back.
Training logEvery sessionIf your lifts hold on a cut, you're keeping muscle. If they climb on a bulk, the weight you're adding is working for you.

Daily bodyweight swings of 1–2 kg are normal and come from water, glycogen, salt, and whatever food is still in your gut. One weigh-in tells you almost nothing. A week's average tells you something. Two or three weekly averages in a row tell you what's actually happening.

Tracking doesn't have to be forever

Track carefully for 8–12 weeks. Treat it as calibration: you're learning what 40 g of protein, 30 g of oil, and a 600-calorie plate actually look like. After that, move to a looser system. Build your week around a few "anchor meals" whose numbers you know. Estimate the rest by hand portions (a palm of protein, a fist of carbs, a thumb of fat, a fist or two of vegetables). Spot-check with one fully tracked week every month or two. If progress stalls, go back to full tracking for two weeks before changing anything else.

07Adjusting: the decision process

Nutrition is a feedback loop. You set a starting point, measure what happens, and adjust. Most people fail because they adjust too often, too hard, or based on the wrong data. Here's the process, and it's the same for every goal.

  1. Wait for enough data. Judge on at least 2 weeks of weekly averages. The first week of any new diet is mostly water moving around, so ignore it.
  2. Check adherence first. Did you hit your calorie and protein targets on at least 90% of days? If not, the plan hasn't failed. It hasn't been tried yet. Fix adherence before you touch the numbers.
  3. Rule out water noise. Look for a new or harder training block, a salty weekend, a bad week of sleep, travel, or illness. Women should compare the same phase of the menstrual cycle month to month, because water retention shifts across the cycle.
  4. Change one thing, a little. Move calories by 100–200 per day (take it from carbs or fat, never protein), or move your daily steps by about 2,000. One change only.
  5. Wait two more weeks, then repeat. Compare the new trend to your target rate from Chapter 5.

That's the whole algorithm. It's deliberately boring. Big, emotional changes are how people crash diets or overshoot bulks. Small, logical changes are how you reach the goal.

08Supplements: what works and what's marketing

Supplements are the last 1–3% of results, and the supplement industry sells them as the first 50%. Get food, sleep, and training right first. Once those are in place, a few supplements have earned their spot.

SupplementVerdictDetails
Creatine monohydrateWorks3–5 g every day, any time, no loading needed. It improves strength and muscle gain over time and is one of the most studied supplements that exists.15 It adds 1–2 kg of water inside the muscle, which is not fat.
CaffeineWorks3–6 mg per kg about 30–60 minutes before training improves performance.16 Stop about 8 hours before bed. Coffee counts.
Protein powderWorks (as food)It's just convenient protein. Useful when whole food makes your target hard to hit.
Vitamin DIf lowWorth it when a blood test shows you're low, or when you get little sun.
Omega-3 (fish oil)If lowWorth it if you rarely eat fatty fish.
Beta-alanineNicheHelps efforts lasting about 1–4 minutes (grappling rounds, 400–800 m). Causes a harmless tingling.
BCAAs / EAAsSkipUseless if you're eating enough protein.
Test boosters, fat burners, most greens powdersSkipLittle to no evidence at the doses sold, and some are risky.

Supplements aren't tightly regulated, and some have been found to contain things not on the label. Buy products that are third-party tested (look for the NSF Certified for Sport or Informed Sport logos). This matters most if you compete in a drug-tested sport.

09Alcohol, sleep, and stress

Alcohol

Alcohol has 7 calories per gram and fills you up about as much as water does. While your body clears it, it stops burning fat. After training, it blunts muscle building: in one study, heavy drinking after exercise cut muscle protein synthesis by roughly 24–37%, even when protein was eaten alongside it.17 It also wrecks sleep quality and loosens your judgment about food. An occasional drink that you count won't erase your progress. Regular drinking will slow it down, and on a cut it's the easiest thing to cut.

Sleep

Sleep may be the most underrated variable in body composition. In one controlled study, dieters on the same calorie deficit spent either 5.5 or 8.5 hours in bed. They lost similar amounts of weight. But the short-sleep group lost 55% less fat and 60% more fat-free mass.18 Short sleep also increases hunger and cravings and makes training worse. Aim for 7–9 hours in bed, at consistent times.

Stress

Stress mostly works against you indirectly. It makes sleep worse, makes you hungrier, and makes you more likely to eat for comfort. It also causes water retention, which can hide fat loss on the scale for a week or two. You can't always remove stress. You can build a plan simple enough to hold up on bad weeks. That's the point of having default meals (Rule 11).

10Myths worth dropping

"Eat six small meals to stoke your metabolism." Meal frequency doesn't change fat loss or muscle gain when total intake is the same.19 Eat as many meals as fit your life and appetite.

"You have 30 minutes after training to get protein in." The "anabolic window" mostly disappears once total daily protein is equal.20 In practice it's several hours wide on either side of a session. Eat a protein meal within a few hours before or after training and you're covered.

"Eating late makes you fat." Your calorie total decides fat gain, not the clock. If eating late leads you to eat more than you planned, that's a behavior problem, not a timing one.

"I have metabolic damage." Metabolic adaptation is real, small, and reversible (Chapter 1). A stall is almost always untracked calories, lower NEAT, or water retention hiding fat loss.

"Clean foods don't count." A calorie of olive oil counts as much as a calorie of candy. Food quality matters because of fullness and health (Chapter 4). It doesn't override energy balance.

"Carbs make you fat." Too many total calories makes you fat. Carbs fuel hard training. Cutting them can help some people eat less overall, which is a legitimate strategy, not magic.

"Starvation mode stops fat loss." Your body doesn't hold on to fat when you're in a real deficit. What looks like a stall is usually water retention during a hard diet, which often lifts suddenly, the so-called "whoosh."

"You can spot-reduce belly fat" / "toning." You can't choose where fat comes off. "Toned" means enough muscle plus low enough body fat to see it. Build muscle, then lose fat.

If you only remember five things

  1. Calories decide your weight. Protein and training decide what that weight is made of. Get the calorie gap right for your goal, then get 1.6–2.2 g/kg of protein (about 1 g/lb) every day.
  2. Estimates are starting guesses. The trend tells you the truth. Weigh daily, look only at weekly averages, and judge over 2–3 weeks.
  3. Adjust slowly and one thing at a time. 100–200 calories or 2,000 steps, then wait two weeks.
  4. Mostly eat whole, single-ingredient foods, and don't drink your calories. Both make the gap easier to hold without willpower.
  5. Sleep, steps, and consistency beat any supplement. The plan you can repeat on your worst week beats the perfect plan you can't.
Part two · about 5 minutes

My Rules

The primer covers what's true. These rules are how I apply it: defaults that make the right choice the easy one. Each has a reason you can check. Where a rule comes from my preference rather than the evidence, I say so.

  1. Fasting is my favorite cutting tool.

    It doesn't burn fat through some special mechanism. It makes a deficit easy: fewer meals, fewer decisions, fewer chances to overeat. Controlled trials show it works as well as any other way of eating less.2122 In people who lift and eat enough protein, it doesn't cost muscle.2425 Put your eating window around your training, hit your full protein target inside it, and start with something like 16:8 (16 hours fasting, an 8-hour eating window). If it makes you binge or miserable, drop it. The deficit is the point, not the clock.

    Not for you if you have a history of disordered eating, take insulin or other blood-sugar-lowering medication, are pregnant or breastfeeding, or are under 18. See Red flags.

  2. Don't drink your calories.

    My default drinks are water, coffee, tea, and milk. On a cut, drop the milk and keep everything else calorie-free: water, black coffee, plain tea. Protein shakes count as food and are allowed. Juice, alcohol, and soda, diet soda included, sit outside the system. Juice and alcohol are out because liquid calories don't fill you up the way food does, so you don't eat less later to make up for them.26 Diet soda is out because I'd rather you lose the taste for sweet drinks altogether. That part is my preference, not something the research requires.27 The one exception runs the other way: on a bulk, milk is the easiest way to add calories when eating more food gets hard.

  3. Protein first.

    Hit 1.6–2.2 g/kg (about 1 g/lb) every day. Build every meal around a protein source, then add everything else.

    It's the macro that most affects body composition and the one that keeps you fullest.

  4. Trust the trend, not the day.

    Weigh yourself every morning. Only act on the 7-day average, and only after 2–3 weeks of data.

    Daily weight swings 1–2 kg from water, salt, glycogen, and food in your gut. One weigh-in is noise.

  5. Change one variable at a time, in small steps.

    Adjust by 100–200 calories a day or about 2,000 daily steps, then wait two weeks.

    If you change three things at once, you can't tell which one worked.

  6. Mostly single-ingredient foods.

    Make 80–90% of what you eat things that look like they did when they were grown, raised, or caught. The other 10–20% is room for life.

    Given the choice, people eat about 500 more calories a day on ultra-processed food.14 Whole food does part of the portion control for you.

  7. Keep a step floor.

    Pick a daily step minimum you can hit on your worst day (8,000–10,000 is a good range) and keep it through every phase.

    NEAT is the part of your calorie burn that quietly shrinks when you diet.1 A fixed number stops that slide.

  8. Sleep is part of the diet.

    7–9 hours in bed, at consistent times. Protect it the way you protect your training.

    On the same diet, short sleepers lost less fat and more muscle.18

  9. Fuel the work.

    Performance comes before appearance. Never run a hard cut during a season, a fight camp, or peak training. If your training falls apart, you sleep badly, you keep getting sick or hurt, or your period stops, you're eating too little for what you're asking of your body. Eat more, and see Red flags.

    Chronic under-fueling has a clinical name, RED-S (Relative Energy Deficiency in Sport). It harms hormones, bones, immunity, and performance.28

  10. Every cut has an end date.

    Pick the finish line before you start, usually 8–16 weeks. After it, spend at least a few weeks eating at maintenance before you start anything new.

    Diets with no end become burnout, and the post-diet binge undoes months of work. A planned end is what makes the result last.

  11. Decide before you're hungry.

    Have 3–5 default meals you know the numbers for. Keep your kitchen stocked with them. Have a plan for your worst day: late, tired, and nothing prepped.

    Hunger and fatigue make you choose worse. Take the decision out of those moments and you remove the problem.

Part three · about 3 minutes each

Goal Playbooks

Pick the playbook for your goal. Get your starting numbers from the calculator. Every playbook uses the same adjustment process from Chapter 7. Only the targets differ.

Playbook

Cut

For losing body fat while keeping muscle and strength.

Calories
Maintenance minus the deficit that gives your target rate. That's usually 300–700 calories below maintenance for most people.
Rate
0.5–1.0% of bodyweight per week. Go toward 0.5% if you're already lean or it's late in the cut. Go toward 1.0% if you're carrying more fat.
Protein
2.0–2.4 g/kg (about 1 g/lb). Don't cut it to save calories.
Fat / carbs
Fat at 0.6 g/kg or more. Carbs fill the rest. Put most of your carbs around training.
Tools
Fasting window (Rule 1), zero-calorie drinks (Rule 2), step floor (Rule 7), high-volume foods: vegetables, fruit, potatoes, lean protein.
Watch
Weekly average weight, waist, strength. Lifts holding steady means you're keeping muscle. Lifts dropping fast means you're cutting too fast or sleeping too little.
Adjust
If loss is slower than target for 2 weeks and adherence was good: −100 to 200 calories or +2,000 steps. If loss is faster than 1%/week or strength drops sharply: +100 to 200 calories.
Switch when
You hit your goal, you reach the end date (8–16 weeks), or diet fatigue sets in (constant hunger, poor sleep, training falling apart). Then go to Maintenance for at least 2–4 weeks.
Playbook

Bulk

For building muscle as fast as your body realistically can, with as little fat as possible.

Calories
Maintenance plus a small surplus: about 150–400 calories a day for most people.
Rate
Newer lifters: 0.25–0.5% of bodyweight per week. Experienced lifters: 0.1–0.25%. Gaining faster adds mostly fat.12
Protein
1.6–2.0 g/kg (0.7–0.9 g/lb). More isn't harmful, but in a surplus the extra calories are usually better spent on carbs.
Fat / carbs
Fat at 0.6–1.0 g/kg. Carbs make up the rest and fuel the extra training volume you should be doing.
Tools
Milk (Rule 2's exception), calorie-dense whole foods (rice, oats, nuts, olive oil, whole eggs), a fourth meal or a shake before bed.
Watch
Monthly weight change, waist, and whether your lifts keep going up. If your waist grows much faster than your lifts improve, the surplus is too big.
Adjust
If gain is below target for 2–3 weeks: +100 to 150 calories. If you gain faster than target, or your waist climbs fast: −100 to 150.
Switch when
You've gained more fat than you're comfortable carrying, the planned phase ends (usually 4–6 months), or a competition or season needs you lighter. Then maintain for a few weeks before cutting.
Playbook

Recomp

For losing fat and building muscle at the same time. Best for beginners, people returning after a layoff, and people with more fat to lose.

Calories
Maintenance to about 10% below. Start at 5% below.
Rate
The scale stays roughly flat or drifts down slowly. Judge progress by waist, photos, and strength, not weight.
Protein
2.0–2.4 g/kg (about 1 g/lb). This is the most important lever in a recomp.
Fat / carbs
Fat at 0.6 g/kg or more. Carbs fill the rest, weighted around training.
Tools
Hard, progressive training matters more here than in any other phase. Without a strong stimulus to build muscle, a recomp is just a very slow diet.
Watch
Waist going down and lifts going up at a steady weight means it's working. Check photos every 4 weeks.
Adjust
If your waist isn't shrinking after 4 weeks: −100 to 150 calories. If your lifts stall and recovery suffers: +100 to 150.
Switch when
Progress stalls for 6–8 weeks despite good adherence. That usually means you've gotten lean or experienced enough that a dedicated cut or bulk will work better.
Playbook

Maintenance

For holding your results, recovering from a cut, or focusing on performance. This is where most of your life should be spent.

Calories
Your true maintenance: the intake that holds your 7-day average flat. After a cut, add back 100–200 calories a week until your weight settles.
Rate
Hold a range of about ±1–1.5% of bodyweight, not a single number.
Protein
1.6–2.0 g/kg (0.7–0.9 g/lb).
Fat / carbs
Whatever split you enjoy and perform best on, with fat above its floor.
Tools
This is the time to move from full tracking to anchor meals and hand portions (Chapter 6). Spot-check with one tracked week each month or two.
Watch
Weekly average weight and waist. If you drift out of your range for 2+ weeks, go back to full tracking for 2 weeks and correct.
Adjust
Same process as always: ±100 to 200 calories or ±2,000 steps.
Switch when
You're rested, your diet doesn't feel like work, and you have a clear goal for the next phase.
Tool · about 3 minutes

Calculator

This gives you a first guess at your targets, using the same rules as the primer and playbooks. Eat to it for 2–3 weeks, track your weight trend, and adjust from real data. Your data wins over this number every time. The example below is filled in for an 80 kg man. Replace it with your own numbers.

Units

If you enter it, the calculator uses a formula based on lean mass (Katch-McArdle). Otherwise it uses Mifflin-St Jeor.

Goal
Daily target
–calories / day

–

Protein
–
–
Fat
–
–
Carbs
–
–
Fiber
–
14 g / 1,000 cal
proteinfatcarbsshare of calories
  • Expected weekly change –
  • Steps floor 8,000–10,000 / day
  • First check-in –
Part four · about 8 minutes

Using AI to Plan Your Nutrition

An AI assistant (Claude, ChatGPT, or similar) is very good at the tedious part of nutrition: turning targets into meals you'll actually eat, building grocery lists, swapping foods, and doing the check-in math without emotion. It's not good at knowing the exact calories in a specific product, and it can't see what you actually ate. Use it as a planning assistant that works inside the system in this kit, not as the source of the system.

How to use it well

Give it the rules first. Every prompt below includes your targets and the key rules, so the AI works inside this system instead of inventing its own. Keep one ongoing chat, or a project if your AI tool supports them, so it remembers your setup.

Be specific about your real life. Budget, cooking skill, how many hours you have on Sunday, the foods you'll never eat, the foods you'd miss. Vague input gets generic meal plans you'll quit within a week.

Verify the numbers that matter. AI can be confidently wrong about calories and protein in specific foods, especially branded products and restaurant meals. Check the label or your tracking app for anything you'll eat often. Once your anchor meals are verified, the rest of the plan is safe to trust within normal error.

Don't use it for medical nutrition. If you have diabetes, kidney disease, an eating disorder history, are pregnant, or take medication affected by diet, your plan belongs with a doctor or registered dietitian. See Red flags.

The prompts

Copy one, fill in the [brackets], and paste it into your AI tool. Start with the setup prompt. The calculator's copy button gives you your targets in a format you can paste straight in.

1 · Setup: set my targets
You're my nutrition planning assistant. Work inside these rules:
- Calories decide weight change; protein and training decide what the change is made of.
- Protein target: 1.6–2.2 g/kg bodyweight (use goal weight if BMI is over 30). Aim higher on a cut or recomp.
- Fat stays at or above 0.6 g/kg. Carbs fill the remaining calories.
- Fiber ~14 g per 1,000 calories.
- Rates: cut 0.5–1.0% of bodyweight/week; bulk 0.25–0.5%/week for newer lifters, 0.1–0.25% for experienced; recomp ~flat scale.
- Mostly single-ingredient foods. No liquid calories except milk and protein shakes (no milk on a cut). No soda, including diet.
- If I'm cutting, I use a fasting window (default 16:8) placed around my training.

Before giving me targets, ask me for anything below that I haven't answered, one short group of questions at a time:
- Age, sex, height, weight, and body fat % if I know it
- Goal (cut / bulk / recomp / maintain) and target date or end date
- Training: what, how often, what time of day
- Average daily steps and job type
- Meals per day I prefer, and whether I'm fasting
- Foods I love, foods I won't eat, allergies or dietary restrictions
- Weekly food budget, cooking skill, and how much time I'll spend cooking

My starting numbers from the calculator (use as a first guess only):
[paste the copied targets here]

Then give me: daily calories, protein, fat, carbs, fiber; my expected weekly rate of change; and a one-paragraph explanation of how you got them. Keep it short.
2 · Build my week: meal plan and grocery list
Using my targets ([calories] kcal, [protein] g protein, [fat] g fat, [carbs] g carbs), build me a simple 7-day eating plan.

Constraints:
- [number] meals per day, eating window [e.g. 12pm–8pm, or "no fasting"]
- I train at [time] on [days]; put more carbs around those sessions
- Budget: about [$ amount] per week
- Cooking: I'm [beginner / comfortable / good] and I'll batch-cook on [day] for about [hours]
- Foods I love: [list]. Foods I won't eat: [list]. Restrictions: [list or none]

Rules:
- Build around 3–5 repeatable "anchor meals" and rotate them. I want simple, not variety for its own sake.
- Every meal starts with a protein source.
- Mostly single-ingredient foods. Each day within ±100 kcal of target and at or above the protein target.
- Give each meal's calories and protein, and each day's totals.

Then give me:
1. A grocery list grouped by store section, with quantities for the week.
2. A batch-cooking plan for [day], step by step, in the order I should do things.
3. A "worst day" backup meal I can make in under 10 minutes from pantry and freezer items.
3 · Weekly check-in: adjust or hold
Weekly check-in. My goal is [cut / bulk / recomp / maintain] at a target rate of [e.g. 0.75% bodyweight per week]. Current targets: [calories] kcal, [protein] g protein, [steps] steps/day.

This week's data:
[paste from the check-in log, or fill in:]
- 7-day average weight this week: [ ]  last week: [ ]  two weeks ago: [ ]
- Days on target (calories within ±100 and protein hit): [ ] of 7
- Average steps: [ ]   Average sleep: [ ] hours
- Waist this week: [ ]  last week: [ ]
- Training: [lifts up / holding / dropping], energy [good / ok / bad]
- Anything unusual: [travel, illness, salty meals, new training block, menstrual phase, stress]

Follow this process exactly:
1. If fewer than 2 weeks of data at current targets, hold and tell me what to watch.
2. If adherence was under 6 of 7 days, don't change targets. Tell me the one habit most likely to fix adherence.
3. Check for water noise (salt, new training, sleep, stress, cycle) before blaming fat.
4. If the trend is off target and adherence was good, change ONE variable: ±100–200 kcal (from carbs/fat, never protein) OR ±2,000 steps.
5. On a cut, if weight is dropping faster than 1%/week or lifts are falling sharply, add calories.
6. Tell me: hold or adjust, the new targets, and why, in three sentences or fewer.
Also tell me if my data suggests I should end this phase (cut end date reached, diet fatigue, stalled recomp for 6–8 weeks).
4 · Eating out and travel
I'm eating at [restaurant name / type of cuisine] [or: traveling for [days] with access to [hotel fridge / microwave / only restaurants / gas stations / airport]].

My targets for the day: [calories] kcal, [protein] g protein. I've already eaten: [what, or "nothing yet"]. Remaining: about [calories] kcal and [protein] g protein.

Help me:
- Pick 2–3 options from the menu [paste the menu or link, or describe] that fit the remaining budget, protein first.
- Give realistic calorie estimates. Restaurant food usually has more oil and butter than you'd expect, so estimate high, not low.
- Tell me the simple swaps to ask for (sauce on the side, double protein, vegetables instead of fries, etc.).
- If I'm traveling: a simple daily template using what's actually available, with 3 portable protein options.
No drinks with calories, except [milk / protein shake] if it fits.
5 · Make my favorite foods fit
I want to keep eating [food / dish / snack] while staying on my targets ([calories] kcal, [protein] g protein per day).

Give me:
1. An honest estimate of the calories and protein in how I usually eat it: [describe your usual portion and how it's made].
2. A rebuilt version that keeps what I actually like about it ([taste / texture / the ritual]) while raising protein and lowering calories. Give the recipe with gram amounts and the new numbers.
3. If it can't be rebuilt without ruining it, tell me the portion that fits my day and what the rest of my meals should look like that day to make room.
Don't make it "healthy" in a way I'll hate. The goal is something I'll still want to eat in month three.
Reference · about 3 minutes

Cheat Sheet

The targets

  • Protein: 1.6–2.2 g/kg (about 1 g/lb). Higher on a cut.
  • Fat: at least 0.6 g/kg.
  • Carbs: whatever calories are left.
  • Fiber: 14 g per 1,000 calories.
  • Steps: 8,000–10,000 a day, every phase.
  • Sleep: 7–9 hours in bed.

Rates per week (% of bodyweight)

  • Cut: −0.5 to −1.0%.
  • Bulk: +0.25 to +0.5% if you're newer, +0.1 to +0.25% if you're experienced.
  • Recomp: about 0. Waist goes down, lifts go up.
  • Maintain: hold within ±1–1.5%.

The adjustment loop

  • Wait 2+ weeks. Ignore week one of anything new.
  • Adherence under 90%? Fix that first.
  • Rule out water: salt, stress, sleep, new training, menstrual cycle.
  • Change one thing: ±100–200 kcal or ±2,000 steps.
  • Never cut protein to save calories.

Hand portions (after you've calibrated)

  • Protein: 1–2 palms per meal (about 25–50 g).
  • Carbs: 1–2 cupped hands.
  • Fat: 1–2 thumbs.
  • Vegetables: 1–2 fists.
  • Men usually take the 2s, women the 1s. Adjust from your trend.

Drinks

  • Always: water, black coffee, plain tea.
  • Not on a cut: milk.
  • Counts as food: protein shakes.
  • Outside the system: juice, alcohol, soda (diet included).

A cut day on 16:8, example

  • Morning: water, black coffee. Walk.
  • 12:00 meal one: big protein serving, vegetables, some carbs.
  • Training mid-afternoon.
  • 17:00 meal two: protein plus most of the day's carbs.
  • 19:30 meal three: protein (Greek yogurt, cottage cheese, or a shake) plus fruit.

Protein sources

Approximate values for cooked or ready-to-eat portions. Labels and brands vary, so check yours. The last column shows how much protein you get per calorie, which is the number that matters on a cut.

FoodPortionProteinCaloriesg per 100 cal
Shrimp100 g24 g10024
Egg whites200 g (~6 whites)22 g10521
Tuna, canned in water1 can, drained (~115 g)25 g12021
Whey protein1 scoop (~30 g)24 g12020
Chicken breast100 g31 g16519
Greek yogurt, nonfat200 g20 g12017
Lean ground beef (93/7)100 g26 g19014
Cottage cheese, 2%200 g21 g16513
Firm tofu150 g~20 g~180~11
Salmon100 g22 g20511
Whole eggs2 large12 g1458
Lentils1 cup cooked (~200 g)18 g2308
Milk, 2%1 cup (240 ml)8 g1207
Tool

Check-in Log

Log your morning weight every day, and whether you hit your targets. The log calculates your weekly averages and the rate of change for you. Once a week, copy the summary into the check-in prompt (AI prompt 3) or run through the adjustment loop yourself.

Your entries are saved only in this browser, on this device. If you clear your browser data they're gone, so copy the summary each week to keep a record. It shows example entries until you add your first real one.

"On target" means calories within ±100 and protein at or above target.

This week avg
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Last week avg
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Weekly change
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On target
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DateWeightStepsSleepTargets
Read this · about 3 minutes

When This Isn't Your Job

This kit is for healthy adults managing their body composition. Some situations need a doctor or a registered dietitian instead of a spreadsheet. Knowing where that line is is part of running your own nutrition well.

Talk to a doctor before starting if

You have diabetes, especially if you take insulin or sulfonylureas, which can cause dangerously low blood sugar when you fast or cut calories. The same goes for kidney or liver disease, heart disease, or any medication whose dose depends on what or when you eat. You're pregnant, trying to become pregnant, or breastfeeding. You're under 18.

Stop and get help if

Food, weight, or tracking starts taking over your thoughts. You feel out of control around food, binge and then restrict, make yourself vomit, use laxatives, or exercise to "earn" or "cancel" food. You feel anxious or guilty when you can't track. None of these are a willpower problem, and tracking harder makes them worse. Stop tracking and talk to a doctor or an eating-disorder specialist. In the US, the National Alliance for Eating Disorders helpline is 1-866-662-1235.

Signs you're under-fueled (RED-S)

You have missing or irregular periods, stress fractures or injuries that keep coming back, frequent colds, constant fatigue, dizziness or fainting, feeling cold all the time, low sex drive, or performance falling for weeks despite good training. These can mean your body is running on too little energy for what you're asking of it.28 Eat more right away and see a doctor, preferably one who works with athletes.

Making weight is not fat loss

Cutting water to make weight for a wrestling, MMA, BJJ, boxing, or powerlifting weigh-in is a completely different process from fat loss, and it carries real risk. Don't do an aggressive water cut on your own. Your fat-loss phase should be over well before fight week, and a cut to make weight should be supervised by an experienced coach, with medical input when the cut is large.

Get bloodwork if

You feel persistently tired despite good sleep and food, you eat a restrictive diet such as vegan or one with many allergies, or you've never had a basic panel. Ask about vitamin D, iron and ferritin (especially if you menstruate), B12, and a lipid panel.

Check it yourself

Sources

The numbers in the text link here. Each source links to the paper or to a PubMed search for its title, so you can read the evidence yourself.

    Where the evidence is still unsettled

    These are areas where good research disagrees or is thin. I've given you my best current read, but treat them as open questions, not settled facts.

    The protein ceiling. The benefit clearly levels off somewhere around 1.6–2.2 g/kg, but exactly where, and whether it's higher during a cut, is still debated. Whether a practical per-meal cap exists is also open, now that a 100 g serving has been shown to work.

    Fasting and muscle in people who don't lift. In lifters eating enough protein, fasting looks neutral for muscle. Without lifting or with low protein, some trials show extra lean-mass loss. An observational report linking very short eating windows to heart disease exists, but it is weak evidence and hasn't been confirmed.

    Artificial sweeteners long-term. Trials show diet drinks help with weight versus sugary drinks and roughly match water. Long-term health effects are still being studied, and major health bodies disagree. Rule 2's no-soda rule is a preference, not a verdict.

    How much metabolism adapts. It's small in most studies, but estimates vary, and the long-term picture is unclear.

    The best bulk rate for advanced lifters. Smaller surpluses look better so far, but there are few studies in well-trained people.

    Diet breaks and refeeds. One trial found that alternating two weeks of dieting with two weeks at maintenance improved fat loss.29 Another in lifters found little difference in body composition, though people felt better on the breaks.30

    Meal timing and body clocks. Whether eating earlier in the day has benefits beyond making it easier to eat less is still an active research question.

    Run Your Own Nutrition, by Andrew Valentine · AndrewValentine.net · Written for healthy adults. It's educational, not medical advice. If something here conflicts with advice from a doctor who knows your situation, follow the doctor.