TDEE for Bulking — Men Age 35-39, Very Active

A bulking phase means eating above your total daily energy expenditure (TDEE) so the extra energy supports muscle growth alongside a structured resistance-training programme. For a 35 to 39-year-old man who is very active — hard exercise or sport on six to seven days a week — the worked example below uses a body weight of 80 kg (176 lb) and a height of 178 cm, and gives a bulking target of 3,339 kcal/day — a surplus of about 350 kcal a day above TDEE. That figure is an estimate built from a published formula, not a personal prescription: your own numbers will differ if your weight, height or daily activity differ from the example.

The worked example is the whole point of this page. Rather than quoting a single number with no working, it shows the Mifflin-St Jeor equation step by step, multiplies the result by the activity factor for a very active lifestyle, and then turns the total into a daily calorie target for bulking. Use the same steps with your own measurements, or use the calculator linked below, and you will get a target matched to you rather than to the example person. Men typically carry more muscle mass than women at the same body weight, which is one reason the worked BMR here is higher: the men's Mifflin-St Jeor equation adds 5 instead of subtracting 161. That extra lean tissue also means a man's calorie needs respond more sharply to training volume — adding a fourth or fifth session a week moves the target more than it would for a lighter person.

Calculate your own TDEE

Your weight, height, age and activity level are almost certainly different from the example above, so run your own numbers with the TDEE calculator. It uses the same Mifflin-St Jeor equation and the same activity multipliers shown on this page, and it also gives cutting, maintenance and bulking targets from a single set of inputs. If you only want the resting figure, the BMR calculator gives that on its own. For a full bulk plan, the bulk calorie calculator turns the same inputs into a daily surplus target.

Related pages and tools:

The formula: Mifflin-St Jeor (1990)

The Mifflin-St Jeor equation is the most widely validated formula for estimating resting energy expenditure in adults. It was published by Mifflin et al. in the American Journal of Clinical Nutrition in 1990 (Mifflin MD et al., Am J Clin Nutr 1990;51(2):241–247), and it is the equation most calculators and many clinical settings use as a starting point. For women it is:

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

For men the final term is +5 instead of −161. TDEE is then the BMR multiplied by an activity factor: 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for very active and 1.9 for extremely active. These multipliers are the standard values used with the Mifflin-St Jeor equation. The World Health Organization (WHO) BMI categories are used where body-mass index is mentioned on this page: under 18.5 underweight, 18.5–24.9 healthy weight, 25–29.9 overweight, and 30 or over obese.

Working through the example for a 35 to 39-year-old man at 80 kg and 178 cm (age 37 in the formula):

  • 10 × 80 kg = 800 kcal
  • 6.25 × 178 cm = 1,112 kcal
  • 5 × 37 years = 185 kcal
  • Constant: +5 kcal

So BMR = 800 + 1,112 − 185 + 5 = 1,732 kcal/day. That is the energy the body would use at complete rest, before any movement, digestion or exercise is counted. Multiplying by the very active factor of 1.725 gives TDEE = 1,732 × 1.725 = 2,989 kcal/day.

Your targets at a glance

Figure Value
BMR (Mifflin-St Jeor) 1,732 kcal/day
Activity level very active (×1.725)
TDEE 2,989 kcal/day
Bulking target 3,339 kcal/day
Safety floor 1,500 kcal/day (men)
Example BMI 25.2 (Overweight, WHO categories)

The example person's BMI is 25.2, which the WHO categories place in the overweight range — but BMI is a screening tool only. It cannot tell muscle from fat, so a lifter with substantial muscle can sit in the overweight range while being lean, and a sedentary person can sit in the healthy range while carrying little muscle. Use BMI alongside waist measurements and body-fat estimates, never on its own.

How activity level changes the number

The same 35 to 39-year-old man at 80 kg and 178 cm has the same BMR of 1,732 kcal/day whatever the lifestyle — but TDEE moves a lot with activity:

Activity level Multiplier TDEE
Sedentary 1.2 2,079
Lightly active 1.375 2,382
Moderately active 1.55 2,685
Very active 1.725 2,989
Extremely active 1.9 3,292

The gap between sedentary and extremely active is 1,213 kcal a day for this person, which is why two people of the same age, sex, weight and height can need very different calorie intakes. It is also why activity level is the input people most often get wrong: be honest about a typical week, not your best week. If you sit most of the day and train three times a week, you are closer to lightly active than moderately active, and using the higher factor inflates the target.

Cutting, maintenance and bulking from the same TDEE

Goal How it is set Daily target
Cutting TDEE − 500 kcal 2,489 kcal/day
Maintenance TDEE 2,989 kcal/day
Bulking TDEE + 350 kcal 3,339 kcal/day

A 500 kcal daily deficit is the standard cutting figure because it works out to roughly 3,500 kcal a week, about half a kilogram of fat a week for most people. The bulking surplus is deliberately smaller — 350 kcal — because muscle grows slowly and a larger surplus mostly adds fat. Maintenance is simply TDEE itself: eat that, and weight should stay roughly stable over weeks, provided activity stays the same.

How to use the 3,339 kcal target

Start at 3,339 kcal a day and hold it for three to four weeks before changing anything. Weigh yourself three to four times a week, first thing in the morning, and compare weekly averages rather than single days — daily weight moves by a kilogram or more with water, glycogen and food volume. The aim is roughly 0.25–0.5 kg of weight gain per month, mostly lean tissue if training is in place. Gaining faster than that usually means most of the extra weight is fat, not muscle; gaining nothing for a month means adding another 150–250 kcal a day.

The late thirties are when the slow decline in muscle mass begins for people who do not train, which makes resistance training more valuable, not less. A bulk at this age is really a muscle-preservation project as much as a muscle-gain one: the surplus supports training, and the training defends the muscle you already have.

Recovery between hard sessions takes a little longer than it did a decade ago, so spacing heavy lower-body days at least 48 hours apart and keeping sleep regular pays off. Protein matters more too — the 1.6–2.2 g per kilogram range on this page is not a luxury at this age, it is the dose the evidence supports for people who lift.

Six to seven hard days a week is a lot of training volume, and a bulk at this level only works if recovery keeps up. Sleep seven to nine hours, keep most sets two reps short of failure rather than grinding every set, and watch for the signs of under-recovery: weights stalling for two weeks, sleep getting worse, resting heart rate climbing. More training is not automatically more muscle.

A surplus only builds muscle if the training demands it. Follow a progressive resistance programme, adding weight or reps over time, and keep protein at roughly 1.6–2.2 g per kilogram of body weight a day — about 128–176 g a day for the 80 kg example. Spread it across three to five meals so each meal carries 25–40 g. The extra calories are best spent mostly on carbohydrate around training, with enough fat to keep meals satisfying; there is no need to force-feed beyond the target.

A sample day at 3,339 kcal

One practical way to hit 3,339 kcal without tracking every gram is to split the day into meals of roughly the sizes below, built from foods you already eat. The split is a starting point, not a prescription — move calories between meals to suit your schedule, and keep protein in every meal.

Meal Approx. calories
Breakfast 835
Lunch 1,002
Dinner 1,002
Snacks 501

Breakfast might be oats with milk, banana and nuts; lunch a rice or pasta bowl with chicken, fish or beans and vegetables; dinner a similar plate with a different protein; snacks a yoghurt, fruit and a handful of nuts, or a milk-based smoothie after training. Drink water through the day and keep alcohol low — it adds calories without nutrients and harms sleep and recovery.

What this number does not tell you

A TDEE estimate is a starting point, not a measurement. The Mifflin-St Jeor equation was validated on population averages, and individual resting metabolic rate varies by roughly ±10% around the prediction because of differences in muscle mass, genetics and health. Two people with identical age, sex, weight and height can have BMRs a few hundred calories apart. The equation also uses total body weight, so it is less accurate for very muscular people (it underestimates) and for people with a high body-fat percentage (it overestimates), because muscle burns more energy at rest than fat does.

Activity multipliers are blunt by design. They compress a whole week of movement, training, work and fidgeting into a single number, and they cannot capture a week that mixes desk days with long hikes, or a job that is physical some days and sedentary on others. Food intake itself also costs energy to digest — the thermic effect of food, roughly 10% of intake — which the multiplier approach folds in approximately rather than measuring. Treat the 3,339 kcal target as a hypothesis: follow it for two to three weeks, watch the weekly weight average, and adjust by 100–200 kcal based on what actually happens.

Body weight is also a noisy signal during a bulk: creatine, extra carbohydrate and extra food volume all pull water into muscle and gut, so the scale can jump a kilogram in the first week without any fat gain. That is normal. Judge the bulk on the four-week trend, on strength in the gym, and on how clothes fit — not on any single morning's weigh-in.

Frequently asked questions

What is the TDEE for a 35 to 39-year-old man who is very active?

For the worked example on this page — 80 kg, 178 cm, age 37 — BMR is 1,732 kcal/day by Mifflin-St Jeor and TDEE is 2,989 kcal/day at the very active multiplier of 1.725. Your own TDEE will differ if your weight, height or activity differ; use the TDEE calculator with your own measurements.

How was the 3,339 kcal bulking target calculated?

It starts from TDEE of 2,989 kcal/day. A 350 kcal daily surplus is added for bulking, giving 2,989 + 350 = 3,339 kcal/day. The target is an estimate, not a prescription, and it should be adjusted from two to three weeks of real weight data.

Does TDEE fall as you get older?

Yes, slowly. In the Mifflin-St Jeor equation the age term subtracts 5 kcal a day for every year of age, so BMR falls by about 50 kcal a decade when weight and height stay the same — and in practice it often falls faster because muscle mass and daily activity tend to decline with age. For this 35 to 39 age band the example uses age 37; recalculate whenever your weight changes by 5 kg or you move into a new age band.

How much protein should a 35 to 39-year-old man eat while bulking?

The published range for people who lift is 1.6–2.2 g of protein per kilogram of body weight a day, which is 128–176 g a day for the 80 kg example. Split it across three to five meals. People with kidney disease should not follow the high end of that range without medical advice — kidney disease changes the answer, so talk to a doctor first.

What if my weight does not move at 3,339 kcal a day?

First check tracking: oils, sauces, drinks and weekend meals are the usual gaps, and a very active week that slips to a quieter one lowers real TDEE. If tracking is honest and the weekly average has been flat for a full month, add 150–250 kcal a day and reassess after another three weeks. If weight is climbing faster than about 0.5 kg a month, trim 100–150 kcal instead — the surplus is meant to build muscle, not fat.

Is a very active activity level right for me?

Very active means hard exercise or sport on six to seven days a week. If that does not describe a typical week for you, pick the level that does and recalculate — the TDEE calculator makes it quick. Overstating activity is the most common mistake and it inflates the target by hundreds of calories a day, which turns a lean bulk into a fast fat gain.

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.