Individuals with goals to change their physique often want to lose fat and build muscle simultaneously. Unfortunately, these goals generally lead to contradictory recommendations related to diet. A new 2021 meta-analysis set out to determine the possibility of achieving both goals at the same time.
Lose fat, gain muscle, and increase strength are often the most universal and common goals amongst people in the gym. However these goals all require much different protocol for diet and energy intake.
Losing fat requires being in an energy deficit causing your body to use stored resources (fat and glycogen) for energy while gaining muscle & strength generally requires being in an energy surplus to support recovery and anabolic processes.
Whether you can lose fat while gaining muscle and strength is a long debated argument which was what this meta-analysis sought to find the answer to.
The reviewed meta-analysis from Murphy et al examined whether a calorie deficit impairs gains in strength and lean mass in response to resistance training.
Here’s what they found:
*Compared to a control diet, energy deficits led to significantly smaller gains in lean mass.
*Energy deficits also led to smaller gains in strength, but the effect size was smaller, and the effect was not statistically significant.
*Impairment of lean mass gains became more pronounced as the caloric deficit got larger, and a deficit of ~500kcals/day was predicted to fully blunt lean mass gains.
If gaining lean mass is your priority, you should avoid a calorie deficit. Plain and simple. Hypertrophy is an energy-intensic process.
The process of building muscle involves the energy cost of resistance training, the energy cost of post-exercise elevations in energy expenditure, the energy cost of increased protein turnover, and several other aspects of increased expenditure that result from gaining more metabolically active tissue and consuming more calories to fuel training. As such, muscle hypertrophy is an energy-intensive process that is optimally supported by a state of sufficient energy availability.
A dieter striving for body recomposition (fat loss while gaining muscle) will have to decide exactly how large of a deficit they can manage without meaningfully impairing hypertrophy potential.
Simultaneous fat loss and skeletal muscle hypertrophy is “more likely among resistance training naive, overweight, or obese individuals.”
Along those lines, readers who are well-trained or substantially leaner than the participants in this meta-analysis might need to adjust their interpretation and expectations, erring toward a smaller daily energy deficit if they wish to accomplish appreciable hypertrophy along the way.
Energy status is reflected by both short-term energy availability and long-term energy stores (i.e., fat mass).
Lifters with higher body-fat levels can probably make considerable strength gains while losing fat, as long as the acute deficit isn’t large enough to threaten hypertrophy, training performance, or recovery capacity.
Similar to adding muscle size while being in a calorie deficit, this is particularly true for lifters who are relatively new to training or have a lot of room for additional strength gains.
- Energy deficits led to significant impairment of lean mass gains and non-significant impairment of strength gains. As the energy deficit grew by 100kcals/day, lean mass effect size tended to drop; a deficit of ~500kcals/day was predicted to fully blunt lean mass gains.
- “Recomposition” (simultaneous fat loss and muscle gain) is possible in certain scenarios, but a sizable calorie deficit typically makes lean mass accretion an uphill battle.
- Large energy deficits threaten lean mass accretion, and extended periods of excessive energy restriction can impair strength gains as well.
- The most direct path to fat loss is a caloric deficit, and a caloric surplus offers the smoothest path to gains in strength and lean mass.