🍚

Am I Bulking or Just Getting Fat? What the Log Shows

By 02apps studio · Published 11 September 2026 · Updated 11 September 2026

Practical answer

A bulk is honest as long as two lines rise together: the scale and the log. Aim for a small surplus that adds roughly 0.25 to 0.5 percent of body weight a week, and weigh in on the same morning each week. Log every set as it happens, and once a week put the weekly weight next to the weight and reps on three or four main lifts. If the scale climbs and the lifts climb, keep eating. If the scale climbs for three weeks while the lifts hold flat, trim the surplus rather than waiting for the mirror to confirm it.

Three kilograms in six weeks, after two years at the same number. The first week of that felt like a win. Somewhere around week five it stopped feeling like one, and now you are checking your waist in the mirror at eleven at night trying to work out whether the shape you spent years building is going under the food.

Why a rising scale is hard to sit with

A bulk asks you to do something that contradicts everything you learned getting lean. A rising scale was the problem; now it is the plan, and you are supposed to be calm about it.

The question you actually have is narrow. You want the extra weight to be muscle, and you want to know in three weeks if it is not, rather than in four months. The mirror will not tell you, because a bulk changes your look slowly and unevenly. The daily scale will not tell you either, because part of those three kilos is food and water sitting in a bigger meal plan. Two bad instruments, and the anxiety fills the gap between them.

One line cannot answer the question

Almost every bulk is judged on body weight alone. That line goes up, as it is supposed to, and then the question of whether the gain is muscle or fat gets answered by feel, which means by mood, which means by whatever the mirror looked like this morning.

The line that answers it is strength. Muscle you have actually built shows up as weight on the bar and reps at that weight, week after week, on a handful of lifts. The Iraki review of off-season nutrition puts sensible gain at roughly a quarter to half a percent of body weight a week precisely because muscle is built at a limited rate, and any surplus past that rate becomes fat.

Which gives the bulk a test. Both lines rising means the food is buying muscle. The scale rising alone means it is going somewhere else, and you find out in weeks. The rest of this page is how to keep the second line without it becoming a second job.

Five habits, none of them involving the mirror

1. Set the gain rate before the first extra meal

Decide the number now, while you are calm. For a lifter past the first year, 0.25 to 0.5 percent of body weight a week is the range the research supports, which at 80 kg is about 1 to 2 kg a month. Beginners can sit at the top because they build muscle faster. Below the bottom of the range you waste months. Above the top it is mostly fat. Writing the rate down turns "am I gaining too fast" from a feeling into a comparison you can make on a Sunday.

2. Weigh in once a week and log it

The daily scale on a bulk is a mood machine. More food and water in you on any given morning swings the reading by a kilogram on its own. Step on it one morning a week, same day, same conditions, and put the number in the Body screen. Strongbro draws every weigh-in as one curve with the distance to your target underneath, so four weekly points show the rate you are actually gaining at, which you can hold against the rate you chose.

3. Log every set as it happens

The second line only exists if the sets are recorded. Evening logging from memory rounds weights up and loses the last set. Record each set between sets. With the keypad your last session is prefilled, so repeating a weight is one tap and adding 2.5 kg is three. With voice logging you tap the mic, say the exercise in a sentence, check the parsed sets and save. Both feed the same log, and every saved set is checked against your history for automatic personal records. That is where a bulk shows up first: a new best at eight reps, then at five, on lifts you were not treating as record attempts.

4. Compare the two lines once a week

Pick three or four main lifts, one squat pattern, one press, one pull, one hinge if you do it, and judge the bulk on those. Once a week, open the weight curve and the estimated one-rep max trend on each lift side by side. Estimated one-rep max beats the top set here, because a bulk often shows up as an extra rep on the third set before it shows up as a heavier bar, and the estimate catches that. The one-rep max calculator shows how the estimate moves with reps.

Three pictures are possible. Both lines rising: change nothing. Both flat for two weeks: the surplus is probably too small, or the program is not asking for progressive overload, and the training gets checked before the food. Scale rising for three weeks with the lifts flat: that is the warning, and it is the picture the mirror would have shown you in month four.

5. Change the food by the numbers

When the weekly review says the surplus is too small, add a small amount and wait two weeks before judging it. When the scale is running ahead of the lifts, take a similar amount out and wait the same two weeks. One change at a time. Protein around 1.6 grams per kilogram of body weight a day is the one intake number worth watching, since the Morton meta-analysis found gains in muscle and strength plateau around there for people who train.

Give the mirror a fixed appointment instead of a nightly audit. A physique scan every four weeks, same light, same pose, gives a per-body-part score and a trend that moves at the speed muscle actually changes. One scan on its own is noise; it moves with lighting and pump as much as with training. Four of them in a row mean something.

The gym progress tracking guide covers the full weekly review these habits sit inside.

Where the gain rate comes from

The rate and the surplus guidance are from the Iraki narrative review of off-season nutrition for bodybuilders and the joint position of the Academy of Nutrition and Dietetics, Dietitians of Canada and the ACSM. The 1.6 g/kg protein figure is the plateau found in the Morton systematic review. The principle that the log is the test, because muscle is built by asking a little more each week, is the ACSM position stand on progression. None of it replaces advice from a clinician if you have a condition that affects weight or appetite.

Setup checklist

Pick three or four main lifts to judge the bulk by, and keep them in the program
Set a weekly gain target of about 0.25 to 0.5 percent of body weight
Weigh in once a week, same morning, same conditions, and log the number
Log every set during the session with the keypad or the mic
Once a week, put the weight curve next to the estimated 1RM trend on the main lifts
Add food only when the scale and the lifts have both stalled for two weeks
Trim the surplus when the scale rises three weeks in a row without the lifts
Take a physique scan every four weeks instead of a mirror check every day

Get Strongbro on the App StoreFree for 3 days. $19.99 once for lifetime.

Frequently asked questions

How fast should I gain weight on a bulk?

Iraki and colleagues, reviewing off-season nutrition for bodybuilders, land at roughly 0.25 to 0.5 percent of body weight a week, which is about 1 to 2 kg a month at 80 kg. Faster gain adds more fat without adding more muscle. Beginners can sit at the top of that range; experienced lifters closer to the bottom.

Lean bulk or dirty bulk, which is better?

A lean bulk, meaning a small surplus, for almost everyone. Muscle is built at a limited rate that a bigger surplus cannot speed up, so the extra food in a dirty bulk becomes fat you later have to cut, which costs weeks of training in a deficit. The one argument for eating aggressively is a very underweight beginner, and even then the rate matters.

How do I know if I am gaining muscle or fat?

Watch the lifts and the scale together over weeks. If the estimated one-rep max on your main lifts climbs at the same time as body weight, most of the gain is doing its job. If body weight climbs for three or more weeks while the lifts hold flat, the surplus is buying weight rather than muscle. A monthly physique scan or photo confirms the trend.

Should I keep bulking if my lifts have stalled?

First check the things that stall lifts on any diet: sleep, attendance, and whether the program asks for progression at all. If those are fine and both the scale and the lifts have been flat for two weeks, add a small amount of food. If the scale is rising but the lifts are not, more food is the wrong fix. Hold the food and look at the training.

How long should a bulk last?

Long enough for the scale and the log to move together, usually 4 to 6 months at a slow gain rate, then a shorter maintenance or cutting phase. Very short bulks never get past the water weight of the first fortnight. Stop earlier if body fat climbs to a point where you feel worse, sleep worse or the lifts stop responding to the extra food.

Do I need to track calories to bulk?

Not necessarily, but you do need the two outputs: weekly body weight and the lifts. Plenty of lifters manage a bulk by adding a fixed extra meal and adjusting it from the weekly scale reading. Calorie tracking helps when the scale will not move, because it shows how much you actually eat. Protein around 1.6 grams per kilogram a day is worth checking.

What this is based on