In short: yes.
But before we get into the biomedical weeds, remember also: this is a conversation about what is possible under optimal conditions.
Our actual advice for someone just starting out is that optimal and realistic rarely go hand-in-hand. Prioritize building consistent health habits over trying to achieve specific performance or body composition goals to start with (goals are still great to have, they just shouldn’t be top priority); and if you have to choose between doing the things below and doing something that you can do consistently, choose the latter every time.
In a general sense, doing the 100% optimal thing is really fucking hard, and if you don’t have extensive experience both lifting weights and counting calories, it’s so hard as to potentially be impossible.
But that’s not to say that if losing fat and gaining muscle at the same time is what you want, it’s not achievable or worth talking about. So: let’s get into some weeds.
Body recomposition, losing fat and building muscle at the same time, is generally regarded as the holy grail of fitness goals.
Common wisdom would tell you it can’t be done at all. The basic argument is that building muscle requires consuming more calories you burn (positive energy balance) while losing fat requires burning more calories than you consume (a negative energy balance).
The common wisdom is at least partially wrong. Certainly the fastest path to muscle building is taking in more calories than you expend while doing some sort of resistance training, but there’s a lot of clinical and anecdotal evidence that shows it’s at least possible to build muscle in a negative energy balance — enough evidence that we can pretty comfortably say that the standard “Calories In, Calories Out” model of muscle gain and fat loss is an important part of the equation, but isn’t the complete answer.
So, how do we accomplish this feat? It’s simple to say, but harder to do: you’ve gotta convince your body that muscle, which is biologically expensive to make and maintain, is worth the energy it takes to do so (resistance training), and give it the substrate to do so (protein), while it’s also dealing with not having enough total energy.
This makes the actual questions at hand:
1) how much protein is enough protein to manage this?
2) what is an effective resistance training plan to accomplish this?
3) are there any advanced strategies we can employ, once we nail the first two?
Once you have those answers, the kind of results you’ll see will probably depend on how long you’ve been consistently training — newbies will almost certainly be able to do this and won’t have to worry about advanced strategies at all. Just nailing the first two is hard enough, and should be plenty.
People that have been lifting weights for years and are nearing their genetic potential will have a much slower job of it. They will have to have strong habits and pay attention to the little things. Even if they get everything right, they may not see any new muscle growth, but instead maintain all of their lean body mass while fat is reduced. This is technically also recomposition: when you’re eating less energy than you’re using, your body should theoretically burn fat and muscle for fuel. Getting it to not burn muscle is a success.
The answer to the daily protein question, based on the evidence, is something much higher than the US RDA of 0.8g/kg of lean body mass/day — probably closer to twice or even 2.5x that, approaching 1g/lb LBM/day. This is because your protein needs, which go up considerably when recovering from resistance training, are even higher when you’re also in a negative energy balance.
Regularly moving heavy things around with multiple joints (resistance training with compound movements) and somehow making it a little harder every time you do it (progressive overload), are going to be the core of any sane resistance training plan, including this one.
There are lots of exercises that work here: barbell lifts, gymnastic-style bodyweight training, even some weight machines; to achieve progressive overload, you can use more weight, more reps, or biomechanically more difficult movements.
Doing regular full-body moderate-intensity higher-volume work (think crossfit, not powerlifting) will probably also help, by keeping the signaling pathways for nutrient utilization, like mTOR, as cranked-up as possible.
Advanced strategies (get the above things right first)
There’s really only one that’s worth getting into in any detail, and that’s calorie or nutrient cycling.
There’s an idea in the fitness world that has a lot of bro-science and baggage around it: the anabolic window. The short version is that your body is better at turning nutrients into muscle right after you do heavy resistance training. Its importance, especially among novices, has become highly exaggerated, but it is real.
As you become more trained and/or are trying to do harder things (like recomposition), this “window of opportunity” for muscle building does in fact get shorter, more important, and potentially worth worrying about again. But even in this case, most people will get most of the benefit of it by eating the majority (50%+) of their calories directly before and after working out.
You can even go farther down this same path, to the point of eating more calories on workout days than non-workout days and employing strategies that help you do this like various forms of intermittent fasting.
Keeping your total calorie deficit low (and specifically tracking it, i.e. weighing and measuring all of your food) would also be beneficial, for similar reasons — the less energy (calories) you give your body to build muscle, the less muscle it can build.
So keeping calories as high as possible while still keeping yourself in a negative energy balance is beneficial, but can infuriatingly slow to the point of madness — you still want to see some progress in a reasonable time frame. For an advanced athlete in the 10-20% body fat range, half a pound a week of weight loss (a daily deficit of around 250-300 calories) is probably a good target to balance the two. A beginner could get away with twice that.
Everything other strategy or tactic we could mention in this section are really just strategies for generally sticking to any plan — focus on process and habit change, batch cook and eat the same few meals over and over, stick to one plan for as long as it works for you, etc; which are all topics for another article.
So if you want to chase recomposition, go for it. Just remember: the “optimal” plan you don’t do consistently is worth a lot less than the “okay” plan you stick to every day. It’s valuable to have big goals and strive toward them, but don’t let perfect get in the way of progress.