Macros for Bulking — Women Age 18-24 (Low-Carb)

For a woman aged 18–24 who is aiming to gain weight deliberately, with most of the gain as muscle rather than fat, the numbers on this page are: 2594 kcal a day, split into 130 g of protein, 127 g of carbohydrate and 174 g of fat. That is the headline result, and everything below shows how it was worked out — the basal metabolic rate from the Mifflin-St Jeor equation (Mifflin et al. 1990), the activity multiplier, the goal adjustment, and the Atwater energy values of 4 kcal per gram of protein, 4 kcal per gram of carbohydrate and 9 kcal per gram of fat (Atwater 1896; USDA). This page uses a low-carbohydrate split — protein set first, carbohydrate capped at 20% of calories, and fat supplying the rest. Note that this is low-carb, not ketogenic: the carbohydrate figure here is well above the 20–50 g a day typical of a ketogenic diet. A bulk only works if the surplus is modest and the training is hard: extra calories without progressive resistance training mostly become body fat, however the macros are split.

The worked example assumes a woman aged 21 weighing 65 kg and 165 cm tall, moderately active — that means exercise or active work on most days, the 1.55 activity multiplier. Those are assumptions for illustration, stated plainly so you can see exactly where every number comes from. Your own weight, height, age and activity level will give different numbers, and the Macro Calculator will work them out for you in seconds.

A macro split is only useful if it is built on a calorie target that fits the goal. A cutting split at maintenance calories will not cut anything, and a bulking split at a deficit will not build anything. So this page starts with the calories, then splits them — in that order, because the order is the whole logic of the thing.

Use the macro calculator for your own numbers

The figures here are for one specific person: a woman aged 18–24, 65 kg, 165 cm, moderately active, bulking. To get your own split, use the Macro Calculator — enter your weight, height, age, sex, activity level and goal, and it returns your calorie target and your protein, carbohydrate and fat in grams. If you want to check the protein figure separately, the Protein Calculator works it out from your body weight and activity alone.

Related macro pages, covering the same calculation for other ages and diet styles:

The formulas, shown and cited

Two published systems do the work on this page. The first is the Mifflin-St Jeor equation for basal metabolic rate (Mifflin et al., American Journal of Clinical Nutrition 1990), which estimates the calories you burn at complete rest:

Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5

Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161

The second is the Atwater system (Atwater 1896; USDA), which gives the energy in food:

Protein: 4 kcal per gram · Carbohydrate: 4 kcal per gram · Fat: 9 kcal per gram

Worked through for this page's assumed woman (65 kg, 165 cm, age 21):

  • BMR = 10 × 65 + 6.25 × 165 − 5 × 21 − 161 = 1415 kcal a day at rest
  • TDEE = BMR × 1.55 (moderately active) = 1415 × 1.55 = 2194 kcal a day
  • Goal adjustment (bulking): 2194 + 400 = 2594 kcal a day

The safety floors apply here and are respected: the target of 2594 kcal is above the minimum safe intake of 1200 kcal a day for women. No target on this page ever goes below 1,200 kcal a day for women or 1,500 kcal a day for men, and nobody should eat below those floors without medical supervision.

The macro split, with the maths shown

Protein is set first, from body weight, because the evidence on protein is the strongest part of sports nutrition. For bulking, the target used here is 2.0 g per kilogram of body weight per day, which sits inside the published range of 1.6–2.2 g/kg for lifters and dieters (Morton et al. 2018) — and above the 0.8 g/kg that covers sedentary adults. At 65 kg, that is 2.0 × 65 = 130 g a day, worth 130 × 4 = 520 kcal.

Then the remaining calories are split according to the diet style. This page uses a low-carbohydrate split, with protein set first, carbohydrate capped at 20% of calories and the rest from fat: 20% of total calories to carbohydrate, with fat taking everything left after protein and carbohydrate.

Macro Grams per day kcal per day % of calories
Protein 130 g 520 kcal 20%
Carbohydrate 127 g 508 kcal 20%
Fat 174 g 1566 kcal 60%
Total — 2594 kcal 100%

Carbohydrate is capped at about 20% of the 2594 kcal target — 508 kcal, or 127 g a day at 4 kcal per gram (the table rounds to the nearest gram so the totals reconcile exactly).

Check the arithmetic: 520 + 508 + 1566 = 2594 kcal, which matches the 2594 kcal target. If those numbers ever disagree on a page like this, the page is wrong — the grams and the calories must always reconcile through the 4/4/9 Atwater values, and on this page they do.

Note what the split does not do: it does not tell you which foods to eat, and it does not say anything about food quality. 130 g of protein from chicken, lentils and Greek yoghurt is not the same diet as 130 g of protein from processed meat, even though the macro table looks identical. The numbers are a framework; the food choices inside the framework are where health actually lives.

What a day of eating looks like

Split across four meals, the daily targets divide roughly as follows. These are illustrative portions for a woman eating 2594 kcal — adjust the foods to your own preferences, allergies and budget, and keep the totals, not the specific dishes.

Meal Protein Carbs Fat
Breakfast 33 g 32 g 44 g
Lunch 33 g 32 g 44 g
Dinner 32 g 32 g 43 g
Snack / post-training 32 g 31 g 43 g

In practice, an even split across meals is a starting point rather than a rule. Many people prefer a larger dinner and a lighter breakfast, or a bigger post-training meal, and that is fine — the daily total is what drives the result, not the per-meal symmetry. Two things do matter at the meal level, though. First, spreading protein across three to five meals of roughly 25–50 g each uses it better than eating most of it in one sitting. Second, the meal after training is the one worth planning properly, with protein and carbohydrate together, rather than leaving it to chance.

Foods that make these numbers easy to hit: for protein, carbohydrate and fat, chicken, fish, eggs, Greek yoghurt and cottage cheese for protein; non-starchy vegetables, berries and small portions of oats or potatoes for the limited carbohydrate allowance; olive oil, butter, nuts, seeds, avocado and full-fat dairy for fat, which carries most of the calories on this split. A single tablespoon of olive oil adds about 14 g of fat and 120 kcal, which is why fat targets are so often overshot by accident — cooking oil is invisible in the macro count unless you measure it.

How to use the result, and when to adjust it

Follow this split for two to three weeks and track your weight, then judge it by the trend. For a bulk, success looks like gaining a few hundred grams a week — fast enough to be building muscle, slow enough that most of the gain is not fat. If you are gaining much faster than that, trim the surplus by 100–200 kcal; if the scale is flat for three weeks, add 100–200 kcal. Weigh yourself at the same time of day several times a week and look at the weekly average.

A low-carbohydrate split needs the most planning around training: carbohydrate is the fuel for hard sessions, so put most of the day's carbohydrate in the meal before and the meal after training. On rest days the same total works, but the timing matters less. Drink enough water and do not cut salt sharply — low-carbohydrate eating changes fluid balance, and headaches in the first week are often a salt and water issue.

If the trend is not moving after three weeks, change one thing by a small amount: adjust calories by 100–200 kcal a day and hold the new level for another two weeks. Do not change the calories, the protein and the training all at once, because then you will not know which change did the work. And do not chase the scale daily — the trend over three weeks is the measurement; a single morning's number is noise.

Age matters to the adjustment, and this page's age band is part of the calculation, not decoration. At this age, training response is usually at its best and recovery is fast, which makes it the easiest decade to build the habits that carry the next twenty years: regular resistance training, enough protein at every meal, and a calorie target you can actually sustain. The risk at this age is not a slow metabolism — it is inconsistency, with big training weeks followed by weeks off, and diets that swing between strict and abandoned. Resistance training two to four times a week is the other half of the plan for this age band: the macros supply the material, the training supplies the signal, and neither works well without the other.

If you are bulking and you train, keep the protein where it is and adjust carbohydrate and fat first when calories need to change. Cutting protein to save calories is the most common mistake in a diet, because it is muscle that gets lost alongside the fat. The protein figure of 130 g is the floor of this plan, not a negotiable extra.

What the macro numbers do NOT tell you

A macro split is an estimate built on an estimate. The Mifflin-St Jeor equation predicts basal metabolic rate for a population average, and any individual can sit 10–15% above or below it. The activity multiplier of 1.55 is a broad band, not a measurement — two people who both describe themselves as "moderately active" can burn very different amounts in a day. That is why the page tells you to track the weight trend and adjust, rather than treating 2594 kcal as a precise prescription.

The split also says nothing about micronutrients, fibre, or food quality. It is entirely possible to hit 130 g of protein, 127 g of carbohydrate and 174 g of fat while eating almost no vegetables, almost no fibre, and far too much salt and added sugar. The numbers are a calorie framework, not a complete diet. A useful rule of thumb alongside them: aim for at least 25–30 g of fibre a day and a plate that is half vegetables at lunch and dinner, and the micronutrient side of the diet largely takes care of itself.

The split also cannot account for medical conditions. Kidney disease changes the protein answer — people with reduced kidney function should not follow a high-protein target without a clinician's guidance. Diabetes changes the carbohydrate answer. A thyroid condition, certain medications, pregnancy and breastfeeding all change the calorie answer. This page is a general-purpose estimate for a healthy adult; if any of those apply, the numbers here are a starting point for a conversation with a professional, not a plan to follow alone.

Finally, the split does not measure adherence. The best macro ratio in the world is worthless if the diet is miserable enough to abandon in a fortnight. A low-carb split that you can sustain for months beats a theoretically perfect split that lasts a week. If this split feels unworkable — if the fat is too low to enjoy food, or the carbohydrate cap makes training feel flat — change the split and keep the calories and the protein, rather than abandoning the plan altogether.

Frequently asked questions

How many calories should a woman aged 18–24 eat for bulking?

On the assumptions used here (65 kg, 165 cm, moderately active), the estimate is 2594 kcal a day — a basal metabolic rate of 1415 kcal times the 1.55 activity multiplier, giving a maintenance level of 2194 kcal, then a 400 kcal surplus for bulking. Your own figure will differ with your weight, height and activity; use the Macro Calculator with your own numbers.

How much protein is 130 g a day in real food?

About four servings of 25–50 g of protein — for example, chicken breast (about 30 g), two eggs with cheese (about 20 g), a portion of oily fish (about 25 g) and a pot of Greek yoghurt (about 20 g). The point of the per-meal table above is that 130 g sounds like a lot as one number and is very manageable split across four meals.

Is this a ketogenic diet?

No. A ketogenic diet typically keeps carbohydrate at 20–50 g a day, while this page's low-carb split allows considerably more carbohydrate than that. This is a moderate low-carbohydrate approach: carbohydrate is capped at 20% of calories, fat supplies the rest, and protein is set first. If you want a ketogenic split, use the keto macro calculator rather than this page.

What should I do first if my weight does not move after three weeks on 2594 kcal?

First, check the trend rather than a single weigh-in — daily weight fluctuates by a kilogram or more. If the three-week average is genuinely flat, adjust calories by 100–200 kcal in the direction of your goal and hold for another two weeks before judging again. Also check the quiet calorie leaks: cooking oil, drinks, sauces and snacks are the usual reason a careful-looking diet is not actually at 2594 kcal.

Why is the protein target 2.0 g/kg instead of 0.8 g/kg?

The 0.8 g/kg figure is the minimum to avoid deficiency in a sedentary adult, not the amount that best supports training and bulking. The published evidence for active people (Morton et al. 2018) supports 1.6–2.2 g/kg for lifters and dieters, and this page uses 2.0 g/kg — inside that range. One exception: kidney disease changes the answer, so anyone with reduced kidney function should check with a clinician before following a high-protein target.

Does age 18–24 change how I should eat these macros?

Yes, in emphasis rather than in arithmetic. At this age, training response is usually at its best and recovery is fast, which makes it the easiest decade to build the habits that carry the next twenty years: regular resistance training, enough protein at every meal, and a calorie target you can actually sustain. The practical consequence is the same at every age: spread the 130 g of protein across the day, train with resistance two to four times a week, and judge the 2594 kcal target by the three-week weight trend rather than by how the first week feels.

Related pages

Estimates only, not medical advice. Minimum safe intakes: 1,200 kcal/day women, 1,500 kcal/day men — consult a healthcare professional before a very-low-calorie diet.