Is body recomposition possible? • Stronger by Science

Body recomposition – gaining muscle while losing fat – is one of the most desirable outcomes in fitness. The idea that you can get leaner and more muscular at the same time sounds almost too good to be true.

Among experienced lifters, though, “recomping” is often dismissed as something that only happens to complete beginners or people using anabolic steroids. Once you’ve been training for a few years, the argument goes, you supposedly must pick a lane: cut or bulk.

But when you dig into the research, the story isn’t quite that simple.

Several studies have compared being in a calorie surplus versus being at maintenance while resistance training  (1, 2, 3, 4). Generally, being in a surplus produces similar or slightly greater gains in muscle size. The rationale is intuitive: extra energy could facilitate recovery, speed glycogen replenishment, and let you train harder or with higher volume – all of which should support hypertrophy.

That said, the difference between a mild surplus and maintenance is smaller than many assume. Most of the studies listed above found improvements in indirect measurements of hypertrophy (e.g. lean body mass), which may be more easily swayed by simply being in a surplus versus truly seeing more hypertrophy.

It’s also clear that you can gain muscle in a surplus in the studies listed above. Additionally, in a meta-regression of 52 training studies, Murphy and colleagues found that being in a deficit clearly reduced muscle gain, but most participants training around maintenance still increased lean mass.

In fact, across hundreds of resistance-training studies, participants are rarely told how much to eat; they simply train while maintaining their usual diet. Bodyweight typically stays stable, yet those same studies almost always report increased muscle size and reduced fat mass simultaneously.

So while a calorie surplus might slightly improve outcomes in some cases, it’s clear that recomposition can and does occur under maintenance conditions.

One common misconception about bulking versus recomping is that the building process of gaining muscle consumes a ton of energy. Therefore, to fuel this process, a calorie surplus is required.

However, that’s simply not true. A review by Slater et al put the metabolic cost of building skeletal muscle mass around 12.7 to 19.5 kJ per gram of muscle mass. That’s equivalent to around 3-4.6 kcal per gram of muscle mass.

Of course, you also need to account for the energy density of skeletal muscle mass. Most estimates put this at around 16.7 kJ per gram of protein.

Let’s assume that you’re the average intermediate lifter. If you’re lucky, you might gain around 2-4lb of muscle in a year. With these figures in mind, the energetic cost of depositing that muscle mass would be around 3,450 to 9,800 kilocalories per year. When you bring that to a daily scale, that means the muscle-building process requires an extra 9 to 27 kcal per day.

There are three reasons this is noteworthy.

First, that’s an incredibly small number of calories.

Second, getting into a calorie surplus of that exact size is practically impossible. Food labels vary by several percent even under controlled manufacturing conditions, and estimating intake in mixed meals introduces far larger errors.

Third, that tiny energetic requirement can almost certainly be met endogenously by mobilizing stored energy from glycogen or adipose tissue.

In short, the act of synthesizing new muscle tissue doesn’t require a measurable surplus on a day-to-day basis.

Rather than seeing “cut,” “recomp,” and “bulk” as rigid modes, it’s more accurate to view them as points on a continuum of energy balance.

Being in a deficit maximizes fat loss, but tends to limit or slightly reverse hypertrophy.

Eating at maintenance allows moderate fat loss and moderate muscle gain simultaneously.

Shooting for a surplus maximizes hypertrophy, but at the cost of some fat gain.

Where you fall on that continuum depends on your training quality, recovery, and current body composition. Someone with higher body fat will have more stored energy to draw from, making recomposition easier. Someone who’s already very lean may struggle to build without a true surplus.

There are a couple of caveats/limitations to note here.

First, training status may or may not matter. Most studies in this area involve relatively untrained or intermediate lifters. As you get more advanced, the total rate of muscle gain slows dramatically. That makes recomposition slower, but not impossible. In practice, both bulking and recomping yield smaller returns. The main difference is in pacing, not feasibility.

Second, there are probably boundaries to when recomping is an effective strategy. At extremely low body fat levels, maintaining calories might limit growth. On the other hand, someone carrying a bit more body fat has plenty of energy reserves to pull from. If you’re well below your natural “settling point,” recomp will be harder to achieve, but if you’re near or above it, it’s surprisingly achievable.

To summarize, body recomposition isn’t a myth: it’s a regular outcome in research, and in practice. The magnitude of change might be modest, especially for advanced lifters, but it happens nonetheless.

A dedicated bulk can still make sense if you’re relatively lean and comfortable adding some fat in pursuit of faster gains. But if you’re already near your long-term target weight or prefer a steadier, leaner approach, staying around maintenance and focusing on progressive training may yield the best balance between strength, muscle gain, and aesthetics.