Resistance training has emerged as an evidence-based therapeutic intervention for obesity management, complementing traditional approaches of dietary modification and aerobic exercise. Whilst caloric restriction and cardiovascular activity remain cornerstones of weight management, growing clinical evidence demonstrates that resistance training offers unique metabolic and body composition benefits. By preserving lean muscle mass during weight loss, resistance training helps maintain resting metabolic rate and may support long-term weight management outcomes. This article examines the clinical evidence supporting resistance training in obesity treatment, explores the physiological mechanisms underlying its effectiveness, and provides practical guidance aligned with UK clinical recommendations for safe implementation in individuals living with obesity.
Summary: Clinical evidence demonstrates that resistance training is an effective component of obesity treatment, particularly when combined with dietary intervention, by preserving lean muscle mass and improving metabolic health markers.
- Resistance training preserves fat-free mass during caloric restriction, helping maintain resting metabolic rate and potentially reducing weight regain risk.
- Systematic reviews show resistance training improves body composition, insulin sensitivity, and cardiovascular risk markers in individuals with obesity.
- UK Chief Medical Officers recommend muscle-strengthening activities on at least two days per week as part of comprehensive obesity management.
- Combined resistance and aerobic training produces superior outcomes compared to either modality alone, according to NICE guidance on obesity management.
- Pre-exercise screening is essential to identify cardiovascular risk factors and obesity-related comorbidities before commencing resistance training programmes.
Table of Contents
- Understanding Resistance Training in Obesity Management
- Clinical Evidence for Resistance Training in Weight Management
- How Resistance Training Affects Body Composition and Metabolism
- Comparing Resistance Training to Other Exercise Interventions
- Implementing Resistance Training: UK Guidelines and Recommendations
- Safety Considerations and Contraindications in Obesity
- Frequently Asked Questions
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Understanding Resistance Training in Obesity Management
Resistance training, also known as strength training or weight training, involves exercises that cause muscles to contract against external resistance with the expectation of increases in strength, tone, mass, and endurance. In the context of obesity management, resistance training has emerged as an important therapeutic intervention alongside dietary modification and aerobic exercise.
Obesity, defined by the National Institute for Health and Care Excellence (NICE) as a body mass index (BMI) of 30 kg/m² or above (NICE CG189), affects a substantial proportion of adults in England. According to the latest Health Survey for England data, approximately 26% of adults are living with obesity, with prevalence varying by age, sex, and ethnicity. Traditional weight management approaches have predominantly focused on caloric restriction and cardiovascular exercise. However, growing evidence suggests that resistance training offers complementary metabolic and body composition benefits that enhance these conventional strategies.
The rationale for incorporating resistance training into obesity treatment stems from its ability to preserve or increase lean muscle mass during weight loss. When individuals lose weight through diet alone or diet combined with aerobic exercise, a proportion of the weight lost may come from lean tissue rather than fat mass. The extent of lean mass loss varies depending on dietary protein intake, the magnitude of energy deficit, and whether resistance training is included. This loss of muscle tissue can reduce resting metabolic rate, potentially contributing to weight regain—a phenomenon sometimes termed 'metabolic adaptation', whereby the body's energy expenditure decreases beyond what would be predicted by changes in body mass alone.
Resistance training addresses this concern by stimulating muscle protein synthesis and promoting muscle hypertrophy, even in a caloric deficit. This preservation of metabolically active tissue may help maintain energy expenditure during weight loss and support long-term weight management. Furthermore, resistance training improves functional capacity, which is particularly important for individuals with obesity who may experience mobility limitations and reduced quality of life.
Clinical Evidence for Resistance Training in Weight Management
A substantial body of clinical evidence supports the role of resistance training in obesity management, though the evidence base continues to evolve. Systematic reviews and meta-analyses have consistently demonstrated that resistance training, particularly when combined with dietary intervention, produces favourable changes in body composition compared to diet alone.
Systematic reviews have analysed data from multiple randomised controlled trials and found that resistance training during caloric restriction results in significantly greater preservation of fat-free mass compared to diet-only interventions. Participants engaging in resistance training typically maintain or even increase lean muscle mass whilst achieving fat loss, resulting in improved body composition despite sometimes modest changes in total body weight.
The evidence for resistance training as a standalone intervention for weight loss is more nuanced. Whilst resistance training alone typically produces smaller reductions in total body weight compared to aerobic exercise or combined interventions, it consistently demonstrates improvements in body composition markers. Research indicates that resistance training can contribute to reductions in visceral adipose tissue—the metabolically harmful fat surrounding internal organs—though aerobic exercise and combined training approaches often yield greater reductions in visceral fat.
Key findings from clinical trials include:
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Improved insulin sensitivity and glycaemic control in individuals with obesity and type 2 diabetes, with meta-analyses showing modest but clinically meaningful reductions in HbA1c
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Reductions in cardiovascular disease risk markers, including modest improvements in blood pressure and lipid profiles
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Enhanced physical function and quality of life measures
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Potential benefits for mental health and self-efficacy
However, it is important to note that individual responses to resistance training vary considerably, and specific weight loss outcomes cannot be guaranteed for all individuals. The effectiveness of resistance training depends on factors including programme design, adherence, nutritional intake, and individual metabolic characteristics.
How Resistance Training Affects Body Composition and Metabolism
The physiological mechanisms through which resistance training influences body composition and metabolism are multifaceted and extend beyond simple energy expenditure during exercise sessions. Understanding these mechanisms helps explain why resistance training represents a valuable therapeutic tool in obesity management.
Muscle protein synthesis and hypertrophy: Resistance training stimulates mechanotransduction pathways within muscle fibres, activating the mammalian target of rapamycin (mTOR) signalling cascade. This promotes muscle protein synthesis, leading to muscle fibre hypertrophy over time. Increased muscle mass contributes to resting metabolic rate, as skeletal muscle is metabolically active tissue that requires energy for maintenance even at rest. Whilst the precise contribution of added muscle to daily energy expenditure is debated, the preservation of lean mass during weight loss helps maintain metabolic rate.
Metabolic adaptations: Beyond changes in muscle mass, resistance training induces several metabolic adaptations that benefit individuals with obesity. These include improved insulin sensitivity through enhanced glucose transporter (GLUT4) expression and translocation in muscle cells, increased mitochondrial density and oxidative capacity, and potentially favourable alterations in adipokine profiles. Some studies suggest that resistance training can reduce circulating levels of pro-inflammatory cytokines whilst increasing anti-inflammatory markers, though findings are heterogeneous across studies.
Excess post-exercise oxygen consumption (EPOC): Following resistance training sessions, the body experiences an elevated metabolic rate as it returns to homeostasis—a phenomenon known as EPOC or the 'afterburn effect'. Whilst EPOC contributes additional energy expenditure beyond the exercise session itself, this effect is typically modest and represents a small proportion of total daily energy expenditure. The magnitude and duration of EPOC vary depending on training intensity and volume.
Hormonal responses: Resistance training influences several hormones relevant to body composition, including growth hormone, testosterone, and cortisol. Acute increases in anabolic hormones following training sessions may support muscle maintenance and fat oxidation, though the long-term significance of these transient hormonal changes remains an area of ongoing research.
Comparing Resistance Training to Other Exercise Interventions
When evaluating resistance training as a treatment therapy for obesity, it is essential to consider how it compares to other exercise modalities, particularly aerobic exercise and combined training approaches. Each intervention offers distinct benefits, and the optimal approach may vary depending on individual circumstances and treatment goals.
Resistance training versus aerobic exercise: Aerobic exercise (such as walking, cycling, or swimming) typically produces greater total energy expenditure during exercise sessions and has been associated with larger reductions in total body weight and visceral adipose tissue in many studies. However, resistance training demonstrates superior effects on preserving or increasing lean muscle mass and offers important improvements in metabolic health markers. Meta-analyses comparing exercise modalities have found that whilst aerobic exercise may produce greater initial weight loss, resistance training results in more favourable long-term body composition changes, with preserved or increased lean mass.
Combined training approaches: Current evidence suggests that combining resistance training with aerobic exercise may offer synergistic benefits for obesity management. NICE guidance on obesity management (CG189 and PH53) acknowledges that multicomponent interventions incorporating both aerobic and resistance training, alongside dietary modification and behavioural support, produce the most robust outcomes. Combined training programmes allow individuals to benefit from the cardiovascular adaptations and energy expenditure of aerobic exercise whilst gaining the muscle-preserving and metabolic advantages of resistance training.
Practical considerations: The choice between exercise modalities should also consider practical factors including:
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Accessibility and equipment requirements: Resistance training can be performed with minimal equipment using bodyweight exercises, though progression may require access to weights or resistance bands
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Time efficiency: Resistance training sessions can be relatively brief (30–45 minutes) whilst still providing substantial stimulus
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Individual preferences and adherence: Long-term success depends heavily on adherence, making personal preference a crucial consideration
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Functional outcomes: Resistance training may offer particular benefits for improving activities of daily living and reducing fall risk in older adults with obesity
Implementing Resistance Training: UK Guidelines and Recommendations
The implementation of resistance training for obesity management should follow evidence-based guidelines whilst being tailored to individual capabilities and circumstances. UK health authorities, including NICE and the Chief Medical Officers, provide recommendations that inform clinical practice.
Current UK physical activity guidelines (UK Chief Medical Officers' Physical Activity Guidelines, 2019) recommend that adults should undertake activities that strengthen muscles on at least two days per week. For individuals with obesity seeking weight management, NICE guidance (CG189) suggests that physical activity programmes should be tailored to individual preferences and capabilities, with a gradual progression in intensity and duration.
Programme design principles for obesity management:
The following principles reflect evidence-based practice guidance (e.g., from the American College of Sports Medicine and the British Association of Sport and Exercise Sciences) and should be individualised to each person's starting fitness, comorbidities, and goals:
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Frequency: 2–3 sessions per week, allowing adequate recovery between sessions targeting the same muscle groups
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Intensity: Moderate to high intensity, typically 60–80% of one-repetition maximum (1RM), though beginners may start with lighter loads focusing on technique
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Volume: 8–12 repetitions per set, 2–4 sets per exercise, targeting major muscle groups (legs, back, chest, shoulders, arms, core)
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Progression: Gradual increases in load, volume, or exercise complexity as strength and confidence improve
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Exercise selection: Multi-joint compound exercises (squats, lunges, rows, presses) supplemented with isolation exercises as appropriate
Referral pathways: Healthcare professionals should consider referring patients with obesity to appropriate services, which may include:
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NHS-commissioned weight management services (Tier 2 lifestyle services) that incorporate supervised exercise
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Exercise referral schemes available through some local authorities
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Specialist obesity services (Tier 3) for individuals with complex needs; local commissioning criteria vary, but NICE CG189 recommends assessment for bariatric surgery for people with BMI ≥40 kg/m² or ≥35 kg/m² with comorbidities
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Physiotherapy services for those with musculoskeletal concerns requiring assessment before commencing resistance training
It is important to note that BMI risk thresholds differ for some minority ethnic groups. NICE guidance (PH46) recommends using lower BMI thresholds (≥27.5 kg/m² for obesity) for people of South Asian, Chinese, other Asian, Middle Eastern, Black African, or African-Caribbean family background.
Professional supervision: Particularly for individuals new to resistance training or those with obesity-related comorbidities, working with qualified exercise professionals (such as those registered with the Chartered Institute for the Management of Sport and Physical Activity, CIMSPA) can ensure safe and effective programme delivery. These professionals can provide instruction on proper technique, appropriate progression, and modifications for individual limitations.
Safety Considerations and Contraindications in Obesity
Whilst resistance training is generally safe and beneficial for most individuals with obesity, certain safety considerations and potential contraindications require careful evaluation before commencing a training programme. Healthcare professionals should conduct appropriate screening and provide individualised advice.
Pre-exercise screening: Before beginning resistance training, individuals with obesity should undergo assessment for cardiovascular risk factors and obesity-related comorbidities. The Physical Activity Readiness Questionnaire (PAR-Q) or similar screening tools can identify those who may require medical clearance. UK resources such as those from the British Association for Cardiovascular Prevention and Rehabilitation (BACPR) and the Association of Chartered Physiotherapists in Cardiac Rehabilitation (ACPICR) provide evidence-based thresholds for safe exercise participation. Individuals with uncontrolled hypertension (systolic ≥180 mmHg or diastolic ≥110 mmHg), unstable cardiovascular disease, or recent cardiac events should obtain medical approval before commencing resistance training.
Musculoskeletal considerations: Obesity places increased mechanical stress on joints, particularly weight-bearing joints such as knees, hips, and ankles. Individuals may present with osteoarthritis, previous injuries, or movement limitations that require exercise modification. Starting with bodyweight exercises, using machines that provide support, or performing seated exercises can reduce joint stress whilst building strength. Proper technique is paramount to prevent injury, and exercises should be performed through a pain-free range of motion.
Cardiovascular responses: Resistance training, particularly when performed with high intensity or using the Valsalva manoeuvre (breath-holding during exertion), can produce acute increases in blood pressure. Individuals should be educated on proper breathing techniques—exhaling during the exertive phase and inhaling during the eccentric phase. Those with cardiovascular conditions may benefit from lower-intensity, higher-repetition protocols initially.
Condition-specific cautions: Certain conditions require additional precautions. For example, individuals with proliferative diabetic retinopathy should avoid heavy lifting and Valsalva manoeuvres due to the risk of retinal haemorrhage. Those with symptomatic hernias or advanced osteoarthritis may require specific exercise modifications.
When to seek medical advice: Patients should be advised to contact their GP if they experience:
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Chest pain, excessive breathlessness, or palpitations during or after exercise
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Persistent joint pain that worsens with activity
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Dizziness, light-headedness, or unusual fatigue
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Any new or concerning symptoms
Absolute contraindications to resistance training are rare but include unstable angina, uncontrolled arrhythmias, acute myocarditis or pericarditis, and severe symptomatic aortic stenosis. Relative contraindications requiring medical assessment and potential modification include moderate to severe aortic stenosis, uncontrolled hypertension (systolic ≥180 mmHg or diastolic ≥110 mmHg), and recent musculoskeletal injury.
With appropriate screening, individualised programming, and gradual progression, resistance training can be safely implemented as an effective component of obesity management for the vast majority of individuals.
Frequently Asked Questions
Does resistance training actually help with weight loss in obesity?
Resistance training helps with obesity management by improving body composition rather than producing large reductions in total body weight alone. Clinical trials show that resistance training preserves or increases lean muscle mass whilst reducing fat mass, particularly when combined with dietary intervention, resulting in favourable metabolic changes even when scale weight changes are modest.
What is the evidence for resistance training compared to cardio for obesity?
Aerobic exercise typically produces greater initial weight loss and visceral fat reduction, whilst resistance training demonstrates superior effects on preserving lean muscle mass and improving long-term body composition. Meta-analyses indicate that combined resistance and aerobic training offers synergistic benefits, which is why NICE guidance recommends multicomponent interventions incorporating both modalities alongside dietary modification.
How often should someone with obesity do resistance training?
UK Chief Medical Officers recommend muscle-strengthening activities on at least two days per week for all adults. For obesity management, evidence-based programmes typically involve 2–3 resistance training sessions weekly, targeting major muscle groups with 8–12 repetitions per set and allowing adequate recovery between sessions targeting the same muscles.
Can I start resistance training if I have obesity-related health conditions?
Most individuals with obesity can safely undertake resistance training with appropriate screening and modifications, though those with uncontrolled hypertension, unstable cardiovascular disease, or certain comorbidities require medical clearance first. Pre-exercise screening using tools like PAR-Q helps identify who needs GP approval, and working with qualified exercise professionals ensures safe programme delivery tailored to individual limitations.
Will resistance training stop me losing muscle when dieting?
Resistance training significantly reduces lean muscle loss during caloric restriction compared to diet alone. Systematic reviews consistently show that individuals engaging in resistance training whilst dieting maintain or even increase muscle mass, which helps preserve resting metabolic rate and may reduce the risk of weight regain after initial weight loss.
How do I get referred to a resistance training programme for obesity on the NHS?
Your GP can refer you to NHS-commissioned Tier 2 weight management services that incorporate supervised exercise, or to local authority exercise referral schemes where available. For complex obesity cases, specialist Tier 3 services may be appropriate, though commissioning criteria vary by region and typically require BMI ≥40 kg/m² or ≥35 kg/m² with comorbidities.
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