Dietetics

Strategies to Limit Muscle Loss During Weight Loss

During weight loss, the primary focus is often on reducing fat mass, but preserving muscle mass is at least as important. Muscle loss can not only reduce strength and performance but also slow metabolism and increase the risk of future weight regain. Fortunately, there are evidence-based strategies that help preserve muscle mass as much as possible during weight loss.

What is required for weight loss?

When an individual has excess body fat, there has been a prolonged positive energy balance. In other words, energy intake has consistently exceeded energy expenditure. This excess energy (calories) is then stored as body fat. The emphasis here is on prolonged, as occasional overeating—for example during a single weekend—will rarely result in meaningful weight gain. Weight loss requires the opposite: a sustained negative energy balance, forcing the body to

What does weight loss consist of when losing weight through dieting?

When an individual is overweight and aims to lose weight, the goal is to reduce fat mass rather than muscle mass. Some loss of muscle mass is often unavoidable. It is important to monitor this and understand which factors influence it.

Body composition

Body weight composition can be expressed in different ways, for example using compartment models. These include the 2-compartment, 3-compartment, and 4-compartment models (see table).

Do not underestimate the importance of muscle mass in older adults

As people age, the decline in muscle mass and muscle strength is inevitable. This has consequences for quality of life and increases the risk of health problems, including fractures, chronic diseases, and even mortality. Fortunately, there are ways to slow down or even reverse this process.

What is ageing?

Ageing is a natural process in which cells gradually lose their ability to function and repair themselves effectively. As a result, muscle mass, bone density, and the elasticity of the skin and blood vessels decline, and cells become less responsive to anabolic stimuli (Wilkinson et al., 2018; Gustafsson et al., 2024). The risk of chronic conditions increases and quality of life decreases. The rate at which this occurs varies between individuals and is influenced by factors such as genetic predisposition, physical activity, nutrition,

How BIA helps distinguish between fat loss and muscle loss in older adults

Unintentional loss of muscle mass and strength occurs relatively frequently in older adults. At the same time, fat mass may either increase or decrease. Both changes can negatively affect health, making it important to distinguish between muscle loss and fat loss. Bioelectrical impedance analysis (BIA) can be used for this purpose.

Unwanted Muscle Loss Is a Problem in Older Adults

Due to natural ageing, body composition changes (Palmer & Jensen, 2022). This often occurs without being directly visible in body weight. Unintentional loss of muscle mass and strength is relatively common among older adults. Natural ageing contributes to this, but inadequate nutrition (insufficient energy and protein intake), physical inactivity, and disease can exacerbate the problem (Larsson et al., 2019).

Below certain threshold values, the condition

Insights into Long-Term Results: The Benefits of Regular BIA Measurements

A scale makes it easy to determine a client’s body weight. However, this provides limited information. BIA measurements (depending on the model) can also provide data on body fat percentage, visceral fat mass, muscle mass, body water, and phase angle. By monitoring this information regularly, it becomes possible to work more purposefully toward an individual’s health and fitness goals.

Weight Alone Says Very Little

Using a simple scale, only body weight can be measured. From this, the Body Mass Index (BMI) can easily be calculated. BMI is the most commonly used measure to express obesity (Heymsfield et al., 2025).

BMI is calculated by dividing body weight by height squared. A BMI of 18.5–25.0 kg/m² is considered normal. A BMI between 25.0 and 30.0 kg/m² indicates overweight, and values above this indicate obesity.

A limitation of BMI

Attention to Muscle Mass Loss in Malnutrition

Malnutrition is an underestimated problem. It is common and has adverse consequences for health. A significant proportion of these consequences result from the loss of muscle mass. It is therefore advisable to measure muscle mass in cases of (suspected) malnutrition. This can support both diagnosis and monitoring of treatment effectiveness.

What Is Malnutrition?

Various definitions of malnutrition are in use. Internationally, the term malnutrition is preferred over undernutrition. The World Health Organization (WHO) applies a broad and general definition, whereas the European Society for Clinical Nutrition and Metabolism (ESPEN) uses a more clinical definition. In the Netherlands, the ESPEN definition is generally followed.

WHO Guidelines

The WHO definition is broad and intended for public health contexts. Malnutrition refers to deficiencies, excesses, or imbalances

What Do the Different BIA Results Mean?

Most people have a clear idea of what body weight represents. Modern BIA equipment goes further and displays a range of results. These data can be useful, but what exactly do they mean?

Classification of Body Composition

Body weight can be classified at different levels:

• Atomic level (carbon, oxygen, nitrogen, etc.)

• Molecular level (fat, protein, water, etc.)

• Cellular level (intra- and extracellular cell mass)

• Functional level (adipose tissue, skeletal muscle, bone tissue, etc.)

• Anatomical level (trunk, arms, legs, etc.)

The most commonly used classification is the molecular level, which can be subdivided into multiple compartments (see Figure 1). The most widely used models are based on two, three, or four compartments (Prado et al., 2025). These compartments can be estimated using bioelectrical impedance analysis (BIA).

Figure 1: Overview of the multi-component model

The Evolution of Body Composition Measurement: From BMI to BIA

Measuring body composition is essential for understanding health status, nutritional status, and the risk of chronic diseases. Over the years, various methods have been developed, ranging from simple anthropometric techniques to advanced technologies that provide detailed information on fat mass, fat-free mass, and body water.

Importance of Body Composition

Assessing body composition provides important insights into nutritional status and can be used as an indicator of overall health (Holmes & Racette, 2021; Jo et al., 2025). Moreover, it enables healthcare professionals to develop personalized health strategies and to monitor responses to interventions.

History of Body Composition Measurement

Today, numerous techniques exist to measure or estimate body composition with varying degrees of accuracy. However, this was not always the case. The need

Exercise Interventions to Improve Body Composition

Exercise interventions aimed at improving body composition focus on increasing muscle mass, reducing fat mass, improving fat distribution, and stimulating bone density. This approach not only helps improve overall health but also contributes to promoting a vital and active life.

Increasing Muscle Mass

To build muscle mass, or to limit its loss, it is necessary to progressively load the muscles and allow sufficient rest for recovery. This stimulates muscle protein synthesis and ensures a positive balance between muscle breakdown and muscle growth (Booth et al., 1991). Resistance training is particularly suitable for this purpose, including in individuals with obesity when combined with an energy-restricted diet (Lopez et al., 2022; Binmahfoz et al., 2025).

Resistance may consist of:

• Free weights: barbells, dumbbells, kettlebells

• Machines: strength equipment