How to Improve Metabolic Age
Metabolic age is often presented as a single number on a body composition scan. Yet behind that number is a deeper indicator of how efficiently your body produces and uses energy compared to others of the same chronological age.
In the UK, nearly 63% of adults are overweight or living with obesity (NHS Digital, 2022), and more than 4.3 million people are living with diagnosed diabetes (Diabetes UK, 2023). Both conditions are closely linked to impaired metabolic regulation and insulin resistance.
At the same time, research published in Science suggests that total daily energy expenditure remains relatively stable between ages 20 and 60 when lean muscle mass and physical activity are maintained (Pontzer et al., 2021). This challenges the common assumption that metabolism inevitably slows early in adulthood.
Metabolic age provides insight into whether your body is functioning efficiently — and importantly, it highlights areas that can be improved through sustainable lifestyle habits.
Quick Jump-To Guide
What Is Metabolic Age? ｜ Why It Matters ｜Key Factors｜Lifestyle Impact｜How to Improve It｜Healthy Recipes｜Frequently Asked Questions｜Final Thoughts
What Is Metabolic Age?
Metabolic age compares your basal metabolic rate (BMR) to the average BMR of individuals in your age group.
Basal metabolic rate represents the number of calories your body requires at complete rest to sustain essential life functions. It typically accounts for 60–75% of total daily energy expenditure (NHS).
Even when you are not moving, energy is being used to:
Maintain heart rhythm and circulation Regulate hormones Support immune function Repair tissues Power the brain (approximately 20% of resting energy expenditure)
If your resting metabolic rate is lower than average for your age, your metabolic age may appear higher. If it is higher than average, your metabolic age may appear lower.
Metabolic age is not a medical diagnosis. It is a comparative marker of metabolic efficiency influenced by body composition, activity levels and nutritional status.
Why It Matters
Metabolism governs how nutrients are converted into ATP (adenosine triphosphate), the molecule that powers cellular activity. Every system in the body — endocrine, digestive, neurological and immune — depends on efficient energy production.
When metabolic regulation is balanced, the body maintains stable blood glucose, efficient fat oxidation and healthy hormone signaling. When impaired, risk increases for:
Type 2 diabetes Cardiovascular disease Chronic inflammation Fatty liver disease
Metabolic age reflects long-term resilience. It provides a window into how well your body adapts to stress, dietary changes and ageing.
Key Factors
Metabolic age is shaped by several interconnected biological systems. Each influences resting energy expenditure and metabolic flexibility.
Muscle and Resting Energy
Lean muscle mass is one of the most influential determinants of resting metabolic rate.
Muscle tissue contains high numbers of mitochondria, which generate ATP. Because muscle is metabolically active, it consumes more energy than fat tissue even when the body is at rest.
Research indicates:
1 kg of muscle burns ~13 kcal per day at rest 1 kg of fat burns ~4–5 kcal per day (Wang et al., 2010)
While these numbers appear modest, cumulative differences in lean mass significantly influence basal metabolic rate over time.
Adults may lose 3–8% of muscle mass per decade after age 30 without resistance training (NIH). This gradual decline lowers resting energy expenditure and can increase fat storage if dietary intake remains unchanged.
Muscle also enhances glucose uptake. During contraction, GLUT4 transporters move to the cell membrane, allowing glucose to enter cells efficiently. This improves insulin sensitivity and stabilises blood sugar.
Maintaining muscle supports:
Higher resting energy expenditure Improved insulin responsiveness Greater physical strength Reduced metabolic ageing
Muscle functions as a metabolic regulator — not merely structural tissue.
Body Fat and Insulin Regulation
Body fat distribution is a major determinant of metabolic efficiency.
Visceral fat — stored around internal organs — is metabolically active and releases inflammatory cytokines that interfere with insulin signalling pathways.
Insulin enables glucose to move from the bloodstream into cells for energy. When insulin sensitivity declines, glucose remains elevated in circulation and the pancreas produces more insulin to compensate.
Sleep restriction alone can reduce insulin sensitivity by up to 25% (Spiegel et al., 1999), demonstrating how lifestyle factors affect metabolic regulation.
When insulin resistance develops, it contributes to:
Elevated blood glucose Increased fat storage Greater metabolic strain Higher risk of type 2 diabetes
Reducing visceral fat improves insulin responsiveness and lowers inflammatory signaling.
Fat tissue is hormonally active and directly influences metabolic ageing.
Nutrition and Cellular Energy
Nutrition directly influences how efficiently cells generate ATP.
Protein has a higher thermic effect than carbohydrates or fats. Research shows:
20–30% of protein calories are used during digestion 5–10% of carbohydrate calories are used 0–3% of fat calories are used (Halton & Hu, 2004)
Micronutrients also play critical roles in metabolic pathways. Iron supports oxygen transport. Magnesium is required for ATP synthesis. B vitamins act as metabolic cofactors. Iodine regulates thyroid hormone production.
The World Health Organization recommends limiting added sugars to less than 10% of daily energy intake to reduce metabolic disease risk.
A nutrient-dense diet supports:
Stable blood glucose levels Efficient mitochondrial function Lean muscle preservation Reduced oxidative stress
Metabolic health depends on nutrient quality as much as energy quantity.
Exercise and Metabolic Adaptation
Exercise remodels metabolism over time.
Resistance training stimulates muscle growth and increases mitochondrial density. Aerobic exercise improves oxygen delivery and enhances fat oxidation capacity.
High-intensity interval training (HIIT) increases excess post-exercise oxygen consumption, meaning metabolic rate remains elevated after activity.
Non-exercise activity thermogenesis (NEAT) — daily movement outside structured exercise — can vary significantly between individuals and meaningfully influence energy expenditure (Levine, 2005).
Regular movement supports:
Preserved lean muscle mass Improved insulin sensitivity Reduced visceral fat Greater metabolic flexibility
Exercise is metabolic conditioning, not simply calorie burning.
Sleep and Hormonal Balance
Metabolic systems are hormonally regulated.
Adults require 7–9 hours of quality sleep per night (NHS). During sleep, the body regulates cortisol, leptin, ghrelin and thyroid hormones.
Insufficient sleep disrupts appetite regulation and glucose metabolism. Chronic stress elevates cortisol, which may promote abdominal fat storage and impair thyroid hormone conversion.
Adequate sleep supports:
Stable appetite signals Improved insulin sensitivity Balanced stress hormones Enhanced metabolic resilience
Sleep is foundational to metabolic health.
How Lifestyle Patterns Impact Metabolic Age
Your metabolic age is shaped not just by genetics, but by long-term lifestyle patterns — the everyday behaviours that influence how efficiently your body produces and uses energy.
In the UK, lifestyle factors around weight, activity, diet and sleep are closely linked to metabolic health indicators such as obesity, insulin resistance and chronic disease risk. These real-world averages help show how lifestyle trends relate to metabolic age:
Around 26.5% of adults in England are classified as obese (with higher excess weight beyond healthy ranges) based on measured BMI data — a trend that contributes to metabolic inefficiency since fat mass affects insulin sensitivity and systemic inflammation.
National diet surveys in the UK indicate portions of the population consume higher than recommended sugar and saturated fats while often not meeting recommended fibre and micronutrient intakes, which can negatively affect metabolic pathways over time.
Physical inactivity patterns in England’s adult population show that many fail to meet recommended activity guidelines, a pattern that hastens loss of lean muscle and lowers resting metabolic rate.
These trends are not just abstract numbers — they reflect behaviours that slowly reshape metabolic efficiency, insulin regulation and energy use.
Sedentary vs. Active Daily Life
A lifestyle with low physical activity — including sitting for long periods and limited movement outside exercise sessions — reduces energy expenditure and promotes loss of lean muscle mass. Since muscle is metabolically active tissue, this downward shift in muscle mass reduces your resting metabolic rate.
UK physical activity monitoring shows many adults do not meet regular activity targets, and these patterns correlate with poorer metabolic outcomes.
Long-term effect: Low activity patterns are associated with increased visceral fat and reduced metabolic flexibility — both key contributors to a higher metabolic age.
Diet Quality Over Time
Sugar-rich, refined carbohydrates and ultra-processed foods contribute to metabolic strain. According to UK nutrition surveys, consumption of sugar, saturated fats and salt exceeds recommended levels for many people, while intake of fibre and important micronutrients is often lower than recommended.
This type of dietary pattern can:
Trigger repeated insulin spikes Promote energy storage rather than utilisation Increase inflammatory signalling
Over years, these responses make your metabolism less efficient — reflected in a higher metabolic age compared to peers with balanced nutrient intake.
Sleep and Recovery Patterns
Sleep and circadian rhythm are deeply tied to metabolic regulation. Short or irregular sleep patterns have been linked to changes in appetite hormones and glucose handling, contributing to insulin resistance and altered energy use.
Although detailed UK sleep data warrants separate reporting, large population studies consistently show that inadequate sleep is part of a cluster of behaviours associated with cardiometabolic health decline.
Long-term effect: Poor sleep amplifies stress hormone responses and reduces metabolic efficiency over time.
Stress and Daily Routine
Chronic stress — from work, caregiving responsibilities, socioeconomic pressures or ongoing lifestyle disruption — elevates cortisol. Long-term cortisol elevation encourages fat storage, particularly around the abdomen, and reduces insulin sensitivity — both hallmarks of metabolic slowing.
While specific UK stress prevalence data is complex, the link between chronic stress and metabolic disruption is well established.
Alcohol, Smoking and Other Habits
Alcohol consumption slows liver fat oxidation, which is central to energy metabolism, while smoking increases oxidative stress that interferes with mitochondrial function — key for efficient energy production and metabolic stamina.
These behaviours cumulatively influence how the body manages energy, fat storage and blood glucose.
How to Improve Metabolic Age
1. Strength Training at Least Twice Weekly
Strength training is one of the most effective ways to improve metabolic age because it increases lean muscle mass — and muscle tissue burns more energy at rest than fat.
When you perform resistance exercises such as squats, lunges, presses or rows, your muscles respond by adapting structurally. They increase in size (hypertrophy) and develop more mitochondria — the cellular powerhouses that produce ATP, your body’s primary energy currency.
How this matters: More muscle → higher resting metabolic rate (RMR) → more calories burned even at rest.
Why it helps metabolic age: Since metabolic age estimates how efficiently your metabolism works relative to others your age, increasing RMR through muscle growth can effectively ‘lower’ your metabolic age.
Research supports that resistance training bluntly counteracts age-related muscle loss (sarcopenia) and helps preserve metabolic function over time.
Recommended approach:
Aim for 2–3 resistance training sessions per week, targeting all major muscle groups.
2. Consuming Adequate Daily Protein
Protein plays a dual role in improving metabolic age:
a. Supports muscle protein synthesis (MPS): Dietary protein provides the amino acids required to build and repair muscle tissue — especially important when paired with strength training.
b. Higher thermic effect: Protein requires more energy to digest compared with carbohydrates and fats (about 20–30% of its energy content), meaning you burn more calories processing protein than many other nutrients.
Why this matters: Increasing protein intake supports muscle maintenance and growth, both of which contribute to a higher resting metabolic rate.
Practical point: Distribute protein intake evenly across meals (e.g., 20–30 g per meal) to continually stimulate muscle protein synthesis.
Note on amounts: While individual needs vary, aiming for around 1.2–1.6 g of protein per kg of body weight per day is often useful (especially in conjunction with resistance training).
3. Increasing Daily Movement and Activity
Daily movement — beyond structured workouts — boosts energy expenditure throughout the day. This concept is known as non-exercise activity thermogenesis (NEAT) and includes walking, using stairs, gardening, standing up regularly and general mobility.
How this matters: NEAT can significantly increase total daily energy expenditure, helping to regulate body composition and metabolic rate.
Why it helps metabolic age: Metabolic age reflects basal metabolic processes as well as overall energy burn. Increasing movement keeps the metabolism active even outside gym sessions.
Small changes like walking after meals improve glucose regulation, which in turn supports efficient metabolism.
4. Reducing Ultra-Processed Foods
What you eat not only affects energy intake but also metabolic pathways.
Ultra-processed foods tend to be high in added sugars, refined carbohydrates and unhealthy fats. These can:
Trigger insulin spikes Lead to greater fat storage Contribute to chronic inflammation
All of these negatively impact metabolic efficiency. Conversely, diets focused on whole foods (lean proteins, whole grains, fruits, vegetables, healthy fats) support stable blood glucose and energy production.
How this matters: Whole foods help maintain balanced insulin response and provide micronutrients required for metabolic processes.
Why it helps metabolic age: Stable glucose and nutrient supply reduce metabolic stress and support long-term energy regulation.
5. Maintaining Regular Sleep Patterns
Regular sleep is one of the most overlooked factors influencing metabolic age because sleep regulates hormones that control appetite, stress response and glucose metabolism.
During consistent sleep cycles, hormones such as cortisol, insulin, leptin and ghrelin stay balanced. Sleeping at similar times each night helps align circadian rhythms, allowing the body to repair tissues, regulate blood sugar and optimise energy production. Adults are generally advised to aim for 7–9 hours of sleep, but in practice many people function best around 7–8 hours, especially when bedtime and wake time remain consistent — for example, sleeping around 11 pm and waking at 6–7 am daily. Dimming lights in the evening helps signal melatonin release and prepares the body for metabolic recovery.
How this matters: Consistent sleep timing → balanced hormones → improved insulin sensitivity → stable energy use.
Why it helps metabolic age: Since metabolic age reflects metabolic efficiency, stable hormonal rhythms support better glucose handling and recovery, helping maintain a younger metabolic profile.
Research shows that irregular or insufficient sleep disrupts appetite hormones and reduces insulin sensitivity, which can impair metabolic function over time.
Recommended approach:
Aim for a consistent sleep window (e.g., 10:30–11 pm to 6–7 am), dim lights before bed, and keep sleep and wake times similar even on weekends.
6. Staying Well Hydrated
Hydration is essential for metabolic health because water supports digestion, nutrient transport and cellular respiration — all processes involved in energy production.
Even mild dehydration can reduce metabolic efficiency by lowering blood volume and slowing nutrient delivery to cells. Proper hydration supports circulation, temperature regulation and mitochondrial function, which helps the body produce ATP more efficiently. During periods like fasting or intense activity, electrolytes become especially important because they help maintain fluid balance and nerve signaling. Adding a small pinch of mineral-rich salt — such as Himalayan salt — to water can help supply trace minerals like sodium, potassium and small amounts of magnesium and calcium that support hydration balance.
How this matters: Adequate hydration → improved circulation → efficient ATP production → better metabolic function.
Why it helps metabolic age: Efficient cellular hydration supports energy production and metabolic stability, contributing to a younger metabolic profile.
Research shows that fluid balance influences metabolic reactions and exercise performance, while electrolyte balance helps maintain nerve and muscle function that underpin metabolic efficiency.
Recommended approach:
Drink water consistently throughout the day, consider adding electrolyte concentrate or hydration sachets during prolonged fasting or exercise, and a small pinch of salt in water can help maintain electrolyte balance when dietary intake is low.
Healthy Recipes
1. Greek Yogurt & Seed Bowl
A high-protein breakfast that supports muscle preservation, satiety and stable blood sugar — key factors for maintaining metabolic efficiency.
Ingredients
200g Greek yogurt
1 tbsp chia seeds
Handful of berries
1 tbsp of cashew nuts, almonds, or pumpkin seeds
Instructions
- Add Greek yogurt to a bowl.
- Sprinkle chia seeds and pumpkin seeds evenly on top.
- Add berries for fibre and antioxidants.
- Stir lightly or leave layered depending on preference.
Nutritional Insight
This bowl provides approximately:
18–22g protein (mainly from Greek yogurt) Healthy fats from seeds Fibre from berries and chia Calcium for muscle contraction Magnesium from pumpkin seeds
Protein helps stimulate muscle protein synthesis and has a higher thermic effect than carbohydrates or fats, meaning more calories are used during digestion. The fibre and fats slow glucose absorption, helping maintain steady energy.
2. Lentil & Quinoa Salad
A balanced plant-based meal combining protein, fibre and slow-release carbohydrates that support stable energy metabolism.
Ingredients
½ cup cooked lentils
½ cup cooked quinoa
Mixed vegetables (e.g., cucumber, tomato, bell pepper)
1 tbsp olive oil
Lemon juice
Salt and black pepper
Optional spices: cumin, paprika or parsley
Instructions
- Cook lentils and quinoa separately according to package instructions and allow to cool slightly.
- Combine lentils and quinoa in a bowl.
- Add chopped vegetables.
- Drizzle with olive oil and lemon juice.
- Season with salt, pepper and optional spices.
- Toss gently and serve warm or chilled.
Nutritional Insight
This dish provides approximately:
10–12g fibre per serving Plant protein supporting muscle maintenance Magnesium from lentils and quinoa Iron supporting oxygen transport Slow-release carbohydrates for stable glucose
Fibre helps regulate blood sugar and supports gut bacteria that influence metabolic health. Magnesium contributes to ATP production and muscle function, while iron supports oxygen delivery for energy metabolism.
3. Chickpea & Spinach Stir Fry
A nutrient-dense dish supporting cellular energy production through minerals and plant protein.
Ingredients
1 cup chickpeas
2 cups spinach
Garlic
Salt and black pepper
Turmeric
Olive oil
Instructions
- Heat olive oil in a pan.
- Add garlic and sauté briefly.
- Add chickpeas and cook for 3–4 minutes.
- Stir in spinach until wilted.
- Add turmeric and season with salt and pepper.
Nutritional Insight
Magnesium comes primarily from chickpeas, while spinach contributes both magnesium and iron. These minerals support muscle function, nerve signalling and ATP production. Chickpeas also provide fibre that stabilises blood sugar and improves satiety.
Turmeric adds anti-inflammatory compounds that may support metabolic health indirectly.
Frequently Asked Questions
What does metabolic age mean?
Metabolic age compares your resting metabolic rate to others in your age group.
Is metabolic age accurate?
It is an estimate based on body composition and energy expenditure, not a medical diagnosis.
How can I lower my metabolic age?
Increase lean muscle mass, improve insulin sensitivity, prioritise sleep and maintain consistent physical activity.
Does metabolism slow with age?
Research suggests metabolism remains stable between ages 20 and 60 if lean muscle mass and activity are maintained (Pontzer et al., 2021).
Can diet alone improve metabolic age?
Diet quality is important, but combining nutrition with resistance training and sleep optimisation produces stronger results.
Final Thoughts
Metabolic age reflects how efficiently your body produces and uses energy compared to others your age.
It is influenced by muscle mass, fat distribution, nutrition quality, daily movement and sleep behaviour.
Improving metabolic age is not about extreme restriction or short-term dieting. It is about building consistent habits that preserve muscle, support insulin sensitivity and strengthen long-term metabolic resilience.
The goal is not simply to burn more calories — it is to function more efficiently over time.
References
Bluecrest Wellness. (n.d.). How to improve your metabolic age.
https://www.bluecrestwellness.com/article/how-to-improve-your-metabolic-age
Cappuccio, F. P., Cooper, D., D’Elia, L., Strazzullo, P., & Miller, M. A. (2011). Sleep duration predicts cardiovascular outcomes: A systematic review and meta-analysis of prospective studies. European Heart Journal, 32(12), 1484–1492. https://doi.org/10.1093/eurheartj/ehr007
Dr. Axe. (n.d.). Metabolism boosters: Top ways to increase metabolism naturally.
https://draxe.com/health/metabolism-boosters/
Healthline. (n.d.). Metabolic age: What it is and how to improve it.
https://www.healthline.com/health/exercise-fitness/metabolic-age
HM Government. (2025). Obesity profile short statistical commentary. Office for Health Improvement and Disparities.
https://www.gov.uk/government/statistics/obesity-profile-may-2025-update/obesity-profile-short-statistical-commentary-may-2025
Levine, J. A. (2005). Nonexercise activity thermogenesis (NEAT): Environment and biology. American Journal of Physiology-Endocrinology and Metabolism, 286(5), E675–E685. https://doi.org/10.1152/ajpendo.00562.2004
NHS Digital. (2022). Health Survey for England 2021: Physical activity in adults.
https://digital.nhs.uk/data-and-information/publications/statistical/health-survey-for-england/2021-part-2/physical-activity
Public Health England. (2020). National Diet and Nutrition Survey results.
https://fingertips.phe.org.uk/profile/obesity-physical-activity-nutrition
Spiegel, K., Leproult, R., & Van Cauter, E. (1999). Impact of sleep debt on metabolic and endocrine function. The Lancet, 354(9188), 1435–1439. https://doi.org/10.1016/S0140-6736(99)01376-8
Wang, Z., Heshka, S., Gallagher, D., Boozer, C. N., Kotler, D. P., & Heymsfield, S. B. (2000). Resting energy expenditure-fat-free mass relationship: New insights provided by body composition modeling. American Journal of Physiology-Endocrinology and Metabolism, 279(3), E539–E545.
