Building Muscle After 40: It’s More Than Protein
What can actually be measured—and why the same intervention may be valuable for one goal but irrelevant for another
Building and maintaining muscle becomes increasingly important after 40.
Muscle supports much more than appearance. It contributes to strength, mobility, joint stability, metabolic health, glucose regulation, bone loading, injury resilience and the ability to remain independent later in life.
Yet many muscle-building plans begin and end with one recommendation:
Eat more protein.
Protein matters—but protein alone does not create muscle.
To determine whether a programme is working, we need to look beyond protein intake and ask three more useful questions:
Is the muscle receiving an adequate training stimulus?
Does the body have the resources and recovery capacity to adapt?
Are we measuring the outcomes that actually relate to the goal?
Protein provides the building material—not the instruction
Dietary protein supplies the amino acids required for muscle repair and growth. However, resistance training provides the primary signal telling the body where and why that tissue is needed.
Without a sufficiently challenging and progressive training stimulus, additional protein may simply provide more nutritional material without producing a meaningful increase in muscle.
Research shows that protein supplementation can enhance gains from resistance training, but its effect is generally modest compared with the importance of performing the training itself. The two work together: resistance exercise provides the signal, while adequate protein supports the response.
For many adults undertaking resistance training, a daily protein intake somewhere around 1.2–1.6 grams per kilogram of body weight may be appropriate, depending on age, health, energy intake, training volume and the individual goal. Higher or lower amounts may be appropriate in particular circumstances.
Importantly, more is not automatically better. Once protein needs are adequately met, continually increasing protein may add little if the real limitation is poor training progression, inadequate sleep, low energy intake, pain, illness or inconsistent participation.
The other parts of the muscle-building equation
A successful programme usually requires several elements working together.
Progressive resistance training
The muscles need to encounter a demand greater than the one to which they are already adapted.
That does not mean every session must use extremely heavy weights. Muscle can be developed across a range of resistance loads when exercises are performed with sufficient effort and progression. Heavier loads are generally more specific for improving maximal strength, while moderate and sometimes lighter loads can still stimulate hypertrophy when appropriately prescribed.
Progress can involve:
Increasing resistance
Performing more repetitions
Improving technique or range of motion
Adding sets
Increasing training frequency
Progressing to a more demanding exercise
Producing the same work with better control
If the training stimulus never progresses, the body has little reason to continue adapting.
Adequate total energy
Muscle is metabolically expensive tissue.
Someone who is chronically under-eating—particularly while trying to lose weight rapidly—may struggle to build muscle even when protein intake appears adequate.
This becomes especially important during weight loss. A falling number on the scale may represent fat loss, muscle loss, fluid change or a combination of all three. If preserving or increasing muscle is a priority, resistance training, adequate protein and an appropriate rate of weight loss all matter.
Recovery and sleep
Training initiates adaptation; recovery allows it to occur.
Poor sleep can reduce training quality, alter appetite and glucose regulation, impair recovery and make consistent exercise more difficult. Persistent stress, excessive training volume and inadequate rest can create a programme that consumes energy without producing the intended result.
Hormonal and metabolic health
Not every plateau is caused by hormones—but relevant health problems can affect muscle development.
Thyroid dysfunction, poorly controlled diabetes, vitamin D deficiency, chronic inflammation, anaemia, low testosterone in men, menopause-related changes, medication effects and other medical conditions may influence strength, energy, recovery or body composition.
Testing should be selected according to the person’s symptoms, history and risk factors. Ordering a large hormone panel without a clinical reason is not the same as conducting a useful assessment.
Creatine and other supportive interventions
Creatine monohydrate is one of the better-researched additions to a resistance-training programme. Evidence suggests that it can improve strength and lean-tissue outcomes in many adults, including older populations.
But creatine illustrates an important principle:
An intervention only makes sense in relation to a defined goal and an appropriate foundation.
Creatine may be useful for someone progressively resistance training to improve strength and muscle. It is far less relevant if the main barrier is uncontrolled pain, inconsistent training, insufficient food, severe sleep disruption or an undiagnosed medical problem.
What can actually be measured?
If the goal is to build muscle, body weight alone is an inadequate measure.
A person can gain muscle while losing fat and see very little change on the scale. Another person can gain weight without gaining meaningful muscle. That is why progress should be evaluated across several dimensions.
1. Body composition
Useful options include:
DEXA-derived lean mass
Bioelectrical impedance when performed under consistent conditions
Limb, waist and hip measurements
Standardised progress photographs
Body weight interpreted alongside other measures
DEXA and bioimpedance estimate lean mass, not pure skeletal muscle. Hydration, glycogen, food intake and measurement conditions can influence the result. Trends are generally more useful than isolated readings.
2. Strength
Strength is one of the most practical measures of functional improvement.
It may be assessed through:
Repetition maximums
Estimated one-repetition maximums
Grip strength
Leg press or squat performance
Push, pull and carry capacity
Progress in resistance, repetitions or total training volume
Strength and muscle size are related but not identical. Improvements in technique and nervous-system efficiency can increase strength before a large change in muscle mass becomes visible.
3. Physical performance
Performance testing helps answer a clinically important question:
Is the additional strength improving what the person can actually do?
Examples include:
Sit-to-stand testing
Walking speed
Stair-climbing ability
Balance
Carrying capacity
Getting up from the floor
Ability to complete daily activities without fatigue
Muscle quantity matters, but muscle function matters more.
4. Recovery
Recovery can be tracked through:
Sleep duration and quality
Persistent muscle soreness
Energy levels
Training readiness
Resting heart rate
Pain or joint irritation
Ability to reproduce or improve performance
If performance is declining while fatigue, poor sleep and soreness are increasing, adding more training may not be the correct intervention.
5. Relevant biomarkers
Laboratory testing is not required to prove every muscle gain. However, selected biomarkers may help identify barriers or monitor health when clinically indicated:
HbA1c and fasting glucose
Full blood count and iron studies
TSH and free T4
Vitamin D
Kidney and liver function
Testosterone and related hormones when symptoms justify testing
Inflammatory markers in an appropriate clinical context
The purpose is not to collect the largest number of results. It is to identify information capable of changing the plan.
The same intervention can be valuable for one goal—and irrelevant for another
This is one of the most important principles in personalised healthcare.
A high-protein diet may be valuable for supporting muscle gain, recovery or preservation during weight loss. It does not automatically treat poor sleep, thyroid disease or severe vasomotor symptoms.
Walking is excellent for cardiovascular health, glucose control and general activity. By itself, it may not provide enough progressive overload to maximise muscle growth.
Creatine may support resistance-training performance. It cannot compensate for a programme that is never performed consistently.
Weight loss medication may help reduce fat and improve metabolic risk. If muscle preservation is not actively addressed, weight loss alone does not guarantee improved strength or function.
The question should therefore never be simply:
“Is this intervention good?”
A better set of questions is:
Good for what?
For whom?
Compared with what?
How will we know whether it worked?
Start with the goal, then build the programme
A useful muscle-building plan after 40 follows a clear sequence:
Define the goal → establish a baseline → select the intervention → measure the response → adjust the plan.
The goal may be larger muscles, greater strength, improved metabolic health, better physical function, injury resilience or preservation of independence. Those goals overlap, but they are not identical—and they should not all be measured in the same way.
Protein is important.
But meaningful muscle development also requires progressive training, adequate energy, recovery, appropriate health assessment and measurements that reflect the actual goal.
Do not simply add another supplement and hope.
Assess. Measure. Strategise. Thrive.
Dr D Michael Elliott MSc. D.C. CFMP Able Bodied Healthcare Chiropractic • Lifestyle & Functional Medicine Better Data. Better Decisions. Better Health.
