Nutrition Lead Emma White (ANutr), MSc Human Nutrition is passionate about how food science applies to the human body, and how the nutrients in what we eat affect us and ultimately have an impact on our health.
Gone are the days when simply aiming for a lower number on the scales is the sole goal. Now, women and men alike are striving for a stronger, healthier body. Enter ‘body recomposition’! While weight loss in the past has often been about getting lighter by simply focusing on losing weight, body recomposition has a dual focus – the aim is to lose fat while gaining muscle at the same time. This is better for overall wellness, as it’s not just about losing fat, but maintaining and building muscle mass too, which we know supports long-term health and fat loss maintenance.
Sounds great, right – but how achievable is it? Very! It just requires a careful balance between your calorie deficit, nutrient intakes and exercise routine. In comparison to losing weight, where the main focus has to be on creating a calorie deficit, building muscle requires us to look more closely at our exercise habits and optimal nutrient intake.
Let’s lean in (pardon the pun) to how we can most effectively switch up the composition of our bodies in a healthy and long-lasting way.
How do we lose fat?
Firstly, let’s look at how we achieve each of the two goals of body recomposition in isolation. When it comes to losing fat, we have to create a calorie deficit. What this does is push our body to utilise stored energy to make up for the shortfall of a smaller daily intake. This stored energy would ideally come from our fat tissue, but in more extreme or long-term energy deficits, muscle can also be broken down and utilised too. This is important to remember when aiming to build muscle while losing fat.
How do we build muscle?
To promote muscle growth within the body, we need to apply enough stress to trigger adaptation. This comes in the form of strength-based exercises, which challenge the muscles and stimulate them to grow stronger. Additionally, growing muscles require a suitable daily supply of protein, as well as adequate rest. We also need enough energy to build muscle, which is why a slight calorie surplus is often recommended if your goal is muscle growth. But, of course, this goes against the number one rule for fat loss. So how do you do both at the same time? Read on for all you need to know.
How do we build muscle while losing fat?
This is all about striking the right balance. You need to create a moderate calorie reduction to promote fat loss, while ensuring the deficit is not so low that it hinders muscle growth and maintenance. Alongside this, an appropriate exercise routine is essential to promote muscle growth, plus macronutrient intakes need to be on point. Here are the key focus areas:
Nutrition
Aim for a moderate calorie reduction rather than a very low-calorie diet for the best results. Research has found that more extreme deficits can lead to a loss of muscle mass,(1), (2), so a decrease of around 10-20% from maintenance calories is generally recommended. Nutrient-wise, it’s recommended to aim for 1.6-2.2g of protein per kg of body weight each day to support muscle growth, maintenance, and recovery. Adequate carbohydrates are also necessary to help fuel workouts and aid recovery; these should make up around 40-50% of total calories. Fats should make up the rest, with between 20-35% of calories coming from total fats, as these support hormone production and cell health.
Exercise
Research suggests that just two days a week of full-body strength training can lead to significant strength and muscle-building outcomes.(3) This should therefore be the minimum to aim for, but more frequent workouts are likely to lead to faster results. If you’re working out on multiple days, aim to mix up the target muscles each day – so, for example, aim for a lower body day followed by an upper body day, or a pull day (lat pull downs and deadlifts) one day and a push day (press up, bench press, squat) the next.
In terms of workload, aim for 3-4 sets of 8-12 reps of each exercise to stimulate muscle growth. If you’re a beginner, start with lighter weights that challenge you by the final set, but don’t necessarily push you to failure. But as you become more experienced and your muscles adapt, you should be lifting heavy enough that you struggle to finish the last few reps to see the best gains. It’s also important to keep progressing your exercise routine as you get stronger, so aim to lift heavier or complete more sets, for example.
As well as strength training, some research supports the use of HIIT training in combination with resistance training to further increase fat loss and overall fitness benefits.(4) Examples could be a 20-minute interval run or a 20-30 minute circuit workout with little rest between exercises. Aim for 1-2 sessions a week alongside consistent strength training.
Rest and recovery
You may have heard the phrase ‘abs are made in the kitchen’. Well, muscle is made while we sleep! Without adequate rest and recovery time, our muscles can’t effectively adapt, so it’s thoroughly important to build in rest days and make sure you’re prioritising 7-9 hours of good quality sleep each night.
As well as this, you should aim to leave at least 48-72 hours between training sessions where the same muscle groups are targeted. Research into training frequency shows two sessions per week is more effective than one, indicating 2-3 days of rest is adequate.(5) This is where alternating the target muscle groups comes in handy if you’re aiming for multiple sessions per week.
What else should I consider?
As well as the above fundamentals, there are other things to consider to help maximise your results:
- Time your nutrition. Ensure your protein intake is spaced out throughout the day and aim to have a protein- and carbohydrate-rich snack/meal within the 1-2 hours post-workout. A carbohydrate-rich snack with some additional protein pre-workout can also help fuel energy levels and promote muscle growth.
- Eat back exercise calories. It’s important to ensure your calorie deficit doesn’t become too big, or it could affect your body’s ability to build muscle. So make sure you’re tracking your exercise and eating back some of the calories if you’ve already built a deficit into your daily intake.
- Track your progress. Keep track of your body measurements to monitor changes in size, as you may not notice such big changes on the scales if you’re building muscle at the same time as losing fat. Also, keep a log of your workouts and the weight you can lift for different exercises to ensure you keep progressing.
- Incorporate deload weeks. If you're training consistently and challenging yourself to lift heavier, it's wise to schedule a lighter week every 6-8 weeks. This is known as a deload, during which you reduce the weight, volume, or intensity of your workouts. Deloading helps prevent injury, reduce fatigue, and allows your muscles and joints the chance to recover fully – ensuring you can continue making progress over the long term.
- Manage expectations. When done correctly, fat loss and muscle building are gradual processes. It’s important to know that these changes won’t come overnight, but with consistency, the benefits will be huge in the long run.
Your recomposition checklist:
- Modest daily calorie deficit – 10-20% of maintenance allowance
- Adequate protein intake – 1.6-2.2g per kg protein per day
- Suitable training programme – at least 2 strength sessions per week