When it comes to optimising for our health, weight loss is a top priority for many. In 2022, 66% of adults aged 18 and over were living with overweight, or obesity (which equates to 13 million people) and is a high-risk factor for a variety of diseases including cancer, cardiovascular diseases, Type 2 Diabetes and musculoskeletal conditions.
We all know that to lose weight, lifestyle factors need to be changed, normally by modifying diet and engaging in regular exercise. When it comes to exercise, many understand that to lose weight, aerobic/ endurance exercise is a common method used to achieve this. Whilst this is crucial for weight loss, strength training and building muscle mass is equally critical in the management of weight loss and managing the associated diseases that come with long term obesity (eg. Type 2 diabetes, cardiovascular disease and musculoskeletal conditions).
Our muscle’s primary role is not just for physical strength, function and appearance; it is also vital for our body’s metabolism and is a great tool in our arsenal for weight loss and long term health.
What is the role of our muscle for metabolism?
- Glucose Regulation: Muscles are the primary site for glucose uptake, playing a critical role in regulating blood sugar levels. When muscles contract during physical activity, they increase glucose uptake independently of insulin, improving insulin sensitivity. This process helps prevent and manage type 2 diabetes, which can be a barrier to weight loss.
- Basal Metabolic Rate (BMR): Muscle mass significantly contributes to the basal metabolic rate (BMR) — the number of calories the body burns at rest. A higher muscle mass means a higher BMR, which aids in maintaining a healthy weight by increasing the number of calories burned even when not exercising. This increased metabolic rate is crucial for creating a caloric deficit, essential for weight loss.
- Fat Oxidation: Muscles are essential for fat oxidation. Increased muscle mass enhances the body’s ability to burn fat, contributing to a leaner body composition. This process is vital for reducing visceral fat, the dangerous fat that accumulates around internal organs and is linked to numerous health problems, including obesity and metabolic syndrome.
So why is resistance training important?
Building muscle mass and strength leads to several beneficial adaptations in the body, enhancing metabolic health and promoting weight loss. Other adaptations include:
- Improved Muscle Protein Synthesis
Resistance training stimulates muscle protein synthesis, a process where the body repairs and builds new muscle fibers. This adaptation is critical for maintaining muscle mass, especially when on a calorie-restricted diet. Preserving muscle mass while losing fat ensures a healthy and sustainable weight loss.
- Enhanced Hormonal Balance
Regular strength training and improving muscle mass significantly influence various metabolic processes critical for weight loss by releasing hormones such as growth hormone (GH), insulin-like growth factor 1 (IGF-1), and testosterone, which promote muscle growth, fat breakdown, and improved body composition. Additionally, muscle contractions enhance insulin sensitivity and release myokines that regulate metabolism, inflammation, and energy expenditure, further supporting weight loss.
- Increased Energy Expenditure
Muscles require a substantial amount of energy to maintain, repair, and grow. The more we build our muscle mass with strength training, the higher the energy demands become, leading to a higher BMR. The continuous turnover of muscle proteins, which involves breaking down old proteins and synthesizing new ones, is an energy-intensive process that contributes to the high metabolic rate of muscles. Strength training increases overall energy expenditure, both during and after exercise. The afterburn effect, known as excess post-exercise oxygen consumption (EPOC), means the body continues to burn calories at an elevated rate even after the workout is over. This increased calorie burn is beneficial for achieving and maintaining weight loss.
- Enhanced Functional Capacity
Building muscle mass and strength enhances functional capacity, making daily activities easier and improving quality of life. This increased functional capacity means better strength, balance, coordination, and endurance, which can lead to a more active lifestyle and further support weight loss efforts.
To learn more about resistance training and ways to manage weight loss, an Exercise Physiologist is a great option as they can develop an individualised training program and provide up to date education to help you achieve your health goals.
