October 15, 2026, 3:02 pm | Read time: 3 minutes
Fat loss and muscle gain are often seen as opposing goals: Losing weight requires a calorie deficit, while muscle building benefits from a calorie surplus. However, by properly coordinating training, nutrition, and recovery, you can achieve both simultaneously: reduce body fat and build muscle. FITBOOK Editor-in-Chief Nuno Alves explains what it takes to do this.
Good Conditions for a Body Recomposition
Body recomposition refers to the simultaneous loss of fat mass and gain of muscle. Studies show this is often successful for people who are new to strength training, returning after a long break, or have a higher body fat percentage. Factors such as age, gender, and individual predisposition also play a role. Here are five key points to focus on.
1. Measure Success Beyond the Scale
Those who lose fat mass and simultaneously build muscle won’t necessarily weigh significantly less. Therefore, it’s worth looking at other progress: Are clothes fitting more loosely? Are strength levels improving? Do you feel more capable?
Especially in a body recomposition, these changes often provide a more accurate picture than the number on the scale. Sustainable progress usually occurs slowly but is much more consistent.
2. Strength Training Is the Key Factor
Alongside nutrition, strength training is crucial. It signals the body to maintain and build muscle. Intensity and regularity are particularly important.
According to the American College of Sports Medicine, two sessions per week for the major muscle groups can be sufficient.1 Whether using dumbbells, machines, bands, or body weight is secondary. The key is to continuously increase the training stimulus. Sports scientist Stuart Phillips emphasizes: “Strength training is one of the most effective things you can do for your long-term health and performance.” His advice: “Just start, push yourself seriously, gradually increase, and stick with it.”
3. Don’t Neglect Endurance Training
Endurance training can also support fat loss. The WHO recommends at least 150 minutes of moderate or 75 minutes of intense activity per week.2
4. Sleep Is Important
Adequate sleep is equally important. Studies show that people with sleep deprivation can lose weight but often lose less fat mass and more fat-free body mass. Seven to eight hours of sleep per night are therefore considered beneficial.
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5. Moderate Deficit Instead of Crash Diet
Those looking to lose weight quickly often reduce calorie intake too drastically. Research suggests that a large energy deficit can significantly hinder or even prevent muscle building.3 Additionally, the body often responds with lower energy expenditure: You feel more tired, move less, and perform worse in training.
For a body recomposition, a moderate calorie deficit is more advisable. A rough guideline is about 0.5 percent weight loss per week, slightly more for those with significant overweight.
Also interesting: “My 5 Most Important Rules for Muscle Building”
6. Protein Protects Muscle
During a diet, protein becomes even more important. It supports the maintenance of muscle mass and provides the building blocks for new muscle. Studies suggest at least 1.9 grams of protein per kilogram of body weight as a sensible guideline when combining strength training with a calorie deficit.4
However, actual needs can vary depending on training volume, age, and body composition. What is clear: Without sufficient protein intake, building or maintaining muscle becomes significantly harder.