Training on a bulk: how to build muscle and strength without extra fat

Building muscle in numbers

Building muscle rests on progressive overload and eating with a small calorie surplus.

Hypertrophy or strength: one plan for both

Muscle and strength grow together, so you don't need two plans. A meta-analysis of 21 studies found that 1RM strength rises more with heavy sets (above 60% 1RM), while hypertrophy is similar with light and heavy loads (Schoenfeld et al. 2017).

So you do compound lifts such as the squat or bench press in the strength range, because those are the lifts you track your strength on, and the other exercises in the hypertrophy range: they build muscle just as well and are easier on the joints.

How to set up training on a bulk: 6 steps

1. Pick a plan with a compound lift for every muscle group, e.g. the 4-day upper-lower plan or the 3-day full body plan.
2. Aim for a gain of 0.25-0.5% of body weight per week and track it with the average of 7 morning weigh-ins.
3. Start at the low end of MEV and, in later blocks, add 1-2 sets to muscle groups that aren't growing.
4. Add reps or weight every week, following double progression.
5. After 4-8 weeks, take a deload and start the next block, as the mesocycle page explains.
6. Every 2 weeks, compare your average weight with the plan and adjust calories using the table in the section on adjusting.

Calories on a bulk: where to start

You set calories on a bulk the same way as on a cut, just in reverse. The formula is only a starting point: Mifflin-St Jeor gets within 10% of resting metabolic rate more often than three other popular equations, but for any one person it can be further off (Frankenfield et al. 2005).

1. Work out your resting metabolic rate with the Mifflin-St Jeor equation (Mifflin et al. 1990): men: 10 × weight in kg + 6.25 × height in cm − 5 × age in years + 5; women: the same, but − 161 at the end instead of + 5. The calorie calculator does this step and the next two for you.
2. Multiply the result by a rough activity multiplier from nutrition guides: about 1.5 if you train 3-4 times a week and have a desk job. More movement during the day puts the multiplier closer to 1.7, less puts it around 1.3.
3. To start, add about 5% to that maintenance number. At 2,600 kcal that's about 2,730 kcal; you'll get to 10-15% in later steps if your weight stalls.
4. For 2 weeks, eat the same amount every day, weekends included.
5. Weigh yourself in the morning, after the bathroom and before eating, ideally every day, and take the average for the whole week. A single weigh-in, such as 1-2 kg more after a weekend, moves with water, salt and food, so you make decisions from the average only.

The first week of a bulk usually shows a bigger jump than planned, because you gain water, glycogen and food sitting in your stomach and gut. That's why you judge the rate only from the second week on.

How to adjust calories every 2 weeks

After each change you wait 2 weeks, because that's how long the average needs to show the effect.

Over time the surplus shrinks on its own, because a heavier body burns more energy. With only a few kilograms gained, though, the difference is small, so a stalled bulk more often means you're eating less than you planned.

Example: the first weeks of a bulk

Progress on your lifts after 8 weeks of a bulk at 0.25-0.5% per week.

Calories and weight over 7 weeks

A man, 75 kg, 180 cm, 25 years old, 4 sessions a week, desk job. Resting metabolic rate from the formula: about 1,750 kcal; maintenance with a 1.5 multiplier: about 2,630 kcal. A 5% surplus is about 130 kcal: start at 2,750 kcal. A rate of 0.25-0.5% is 0.2-0.4 kg per week.

Over 7 weeks there was one change, and weight went up 1.5 kg, part of it water and glycogen from the first week. Estimating maintenance from your weight works differently on a bulk than on a cut: we count a kilogram gained roughly as 5,000 kcal, less than a kilogram lost, because in lean people 60-70% of the gain is lean tissue (Forbes 2000). So maintenance is your average calories minus your weekly gain in kg × 700; 5,000 and 700 are our simplification, not a study result. Weeks 4-7 (2,950 kcal, +0.22 kg on average) give about 2,950 − 150, or 2,800 kcal, close to the formula.

Common situations on a bulk

Your weight is flat despite an adjustment. On a bulk this most often means you're eating less than you think: appetite drops, meals get skipped on busy days. Add 150-200 kcal and give it another 2 weeks; one extra snack is easier than making every meal bigger. In women, body weight is higher in the mid-luteal phase than in the mid-follicular phase (Kosar et al. 2022), so compare the same phase of the cycle or look at 4 weeks instead of 2.

Your weight goes up, but your strength doesn't. If the average is rising on pace, food isn't the problem, and more calories will add mostly fat. Check your training: whether you add reps or weight every week with progressive overload, how many sets that muscle group gets, and whether your last deload was a long time ago.

Common mistakes

1. Too big a surplus. In trained lifters, faster weight gain mostly increased skinfold thickness, that is, fat; squat strength and muscle thickness rose about the same with every surplus (Helms et al. 2023). In athletes with a bigger surplus, body weight rose 3.9% vs 1.5% and fat mass 15% vs 3%, while lean mass didn't differ between the groups (Garthe et al. 2013).
2. Only light sets. Your muscles will grow, but your 1RM will go up less; keep the heavy compound lifts.
3. An endless bulk. A bulk ends with a cut; how to plan one is covered in training on a cut.

What the research says

Building muscle in SmartWorkout

1. On the Workout tab, pick a ready-made plan or build your own in the plan creator.
2. Log your body weight on the “Weight” screen; once you set a goal weight, you'll see how much is left “to goal”.
3. When the plan ends, extend it with another block: while editing the plan, long-press the tab of the last block and choose “Clone”.

The SmartWorkout app doesn't count calories or your weekly average weight: the calorie calculator gives you your starting calories, the rules above give you the adjustments, and the “Weight” screen shows all your weigh-ins on a chart. Whether the bulk is turning into strength you can check on the exercise chart: your estimated 1RM on the main lifts should go up from block to block.

You can count weekly sets per muscle group in the volume calculator and your starting calories in the calorie calculator.