Macros for Bulking — Men Age 35-39 (Low-Carb)

For a man aged 35–39 who is looking to gain muscle with as little fat gain as possible, the numbers on this page are: 3163 kcal a day, split into 170 g of protein, 158 g of carbohydrate and 206 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).

The worked example assumes a man aged 37 weighing 85 kg and 178 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 Keto 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 man aged 35–39, 85 kg, 178 cm, moderately active, bulking. To get your own split, use the Keto 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 tool works it out from your body weight and activity alone.

Related macro pages in this batch, covering the same calculation for other goals, 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 man (85 kg, 178 cm, age 37):

  • BMR = 10 × 85 + 6.25 × 178 − 5 × 37 + 5 = 1782 kcal a day at rest
  • TDEE = BMR × 1.55 (moderately active) = 1782 × 1.55 = 2763 kcal a day
  • Goal adjustment (bulking): 2763 + 400 = 3163 kcal a day

The safety floors apply here and are respected: the target of 3163 kcal is above the minimum safe intake of 1,500 kcal a day for men. 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 85 kg, that is 2.0 × 85 = 170 g of protein a day, worth 170 × 4 = 680 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 170 g 680 kcal 21%
Carbohydrate 158 g 633 kcal 20%
Fat 206 g 1850 kcal 59%
Total — 3163 kcal 100%

Check the arithmetic: 680 + 633 + 1850 = 3163 kcal, which matches the 3163 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. 170 g of protein from chicken, lentils and Greek yoghurt is not the same diet as 170 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 man eating 3163 kcal — adjust the foods to your own preferences, allergies and budget, and keep the totals, not the specific dishes.

Meal Protein Carbs Fat
Breakfast 42 g 40 g 51 g
Lunch 42 g 40 g 51 g
Dinner 42 g 40 g 51 g
Snack / post-training 42 g 40 g 51 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, chicken breast, eggs, Greek yoghurt, cottage cheese, lentils, tofu and tinned tuna; for carbohydrate, oats, rice, potatoes, wholemeal bread and fruit; for fat, olive oil, nuts, seeds and avocado. 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, not by a single weigh-in. For bulking, success looks like aiming for slow, mostly lean weight gain of roughly 0.25–0.5 kg a week. Weigh yourself at the same time of day, in the same conditions, several times a week, and look at the weekly average — daily weight moves by a kilogram or more with water, food and glycogen, and none of that is fat.

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 age 37, recovery is slower than at 25, muscle is harder to keep without resistance training, and protein matters more rather than less — which is why the protein target here is set at 2.0 g/kg rather than the sedentary 0.8 g/kg. 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 170 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 3163 kcal as a precise prescription.

The split also says nothing about micronutrients, fibre, or food quality. It is entirely possible to hit 170 g of protein, 158 g of carbohydrate and 206 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 man aged 35–39 eat for bulking?

On the assumptions used here (85 kg, 178 cm, moderately active), the estimate is 3163 kcal a day — a basal metabolic rate of 1782 kcal times the 1.55 activity multiplier, giving a maintenance level of 2763 kcal, plus a 400 kcal surplus. Your own figure will differ with your weight, height and activity; use the Keto Macro Calculator with your own numbers.

How much protein is 170 g a day in real food?

About four servings of 25–30 g of protein — for example, a chicken breast (about 30 g), a pot of Greek yoghurt (about 20 g), two eggs with beans (about 20 g) and a portion of lentils or fish (about 25 g). The point of the per-meal table above is that 170 g sounds like a lot as one number and is very manageable split across four meals.

Is 59% fat too much on a low-carb diet?

Fat is not the enemy of a bulking diet — total calories are what decide the outcome. At 206 g of fat a day, this split keeps fat at 59% of calories, which is well within normal dietary ranges, and fat is what keeps meals satisfying and carries the fat-soluble vitamins. What matters is that the total stays at 3163 kcal and the protein stays at 170 g; the balance between carbohydrate and fat is largely a matter of preference and training demands.

Should I count macros every day?

Counting is most useful as a learning tool. Two to four weeks of tracking teaches you what 170 g of protein and 158 g of carbohydrate actually look like on a plate, and after that many people can eat to the same pattern without weighing everything. If tracking becomes stressful or obsessive, stop — the numbers are a tool, not a test, and a relaxed eater who roughly follows the pattern will outperform a stressed eater who tracks perfectly for a month and then quits.

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.

What if my weight does not change after three weeks on 3163 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 (up if bulking) 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 3163 kcal.

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.