Fast Metabolism and Does it Actually Exist? An Evidence-Based Guide

Your metabolism describes the sum of the continuous chemical reactions taking place in your body every second to keep you alive and functioning. This includes breathing, regulating temperature, repairing cells, and supporting digestion, movement, and thinking.

This article explains whether a fast metabolism truly exists and how lifestyle factors influence it to support long-term health. To be clear, no single food can magically speed it up. Claims suggesting otherwise are often marketing strategies, not science. While some people naturally have a faster metabolism, the most effective ways to support metabolic health involve sustainable lifestyle choices like building lean muscle, staying active, and prioritising sleep, rather than relying on so-called ‘miracle foods’.

Metabolism refers to all chemical processes in your body, while metabolic rate is the amount of energy your body uses over time. Daily energy expenditure includes:

1. Basal Metabolic Rate (BMR)
The energy needed to sustain life at rest. This accounts for the majority of daily calorie use. BMR is influenced by age, sex, genetics, body composition, and hormones.

2. Thermic Effect of Eating (TEE)
The energy required to digest and process food (around 10% of intake). Protein has the highest thermic effect.

3. Physical Activity
All movement, including exercise, walking, fidgeting, housework, and intense workouts.

People are thought to have a fast metabolism when their BMR is higher. A higher BMR is largely determined by lean body mass. More muscle increases calorie expenditure at rest.

Read more about Protein for Vegans here.

Some individuals naturally have a fast metabolism and burn more calories at rest. However, metabolic rate alone does not dictate body weight. People with higher body weight often have:

Lean body mass is the single most important factor influencing metabolic rate (Zampino et al., 2020). Weight management is more strongly affected by diet, activity levels, and habits than by having a ‘slow’ or ‘fast’ metabolism.

The trillions of microbes in your gut influence energy regulation, appetite, inflammation, and how efficiently you extract calories from food.

A diverse, well-nourished microbiome can support healthier metabolic function over time.

Many products claim they can speed up your metabolism and help you burn calories. These claims are misleading, and there are no shortcuts to our bodies' biology.

Supplements like green tea extract or caffeine may slightly increase energy expenditure or improve exercise performance. These effects are insignificant compared to physical activity, protein intake, or maintaining muscle mass.

Instead of trying to ‘speed up’ metabolism, focus on supporting the systems that regulate it. Key strategies include:

These evidence-based habits help preserve lean mass, maintain energy balance, and support a healthy, resilient metabolism over time.

Calo provides convenient, nutritionally balanced meals to support a healthy metabolism, taking the stress out of everyday eating. Download the Calo app to explore our meal prep service, offering delicious, protein-rich dishes with fibre and healthy fats delivered straight to your door.

It is the process by which your body converts food into energy, and it’s important because it powers all essential functions that keep you alive and healthy.

No single food can dramatically speed it up. While some foods like protein-rich meals may slightly increase calorie expenditure through digestion, the most effective way to support a healthy fast metabolism is through consistent lifestyle habits such as strength training, staying active, eating balanced meals, and getting quality sleep.

Increase metabolism by maintaining lean muscle through strength training, staying active, eating protein-rich meals, and prioritising sleep.

Metabolic age compares your basal metabolic rate to the average BMR of your chronological age, reflecting how efficiently your body uses calories.

Metabolism is far more complex than simply how ‘fast’ your body burns calories. It underpins every biological process that keeps you alive. While metabolic rate is strongly influenced by genetics and body composition, lifestyle choices, particularly diet, physical activity, sleep, and gut health, play a significant role in supporting long-term metabolic wellbeing.

Extreme calorie restriction or reliance on ‘boosting’ products can actually slow metabolic function rather than improve it. By focusing on sustainable, evidence-based habits, you can support a healthy metabolism. Read more about matcha for energy and the benefits of turmeric, and more health-related topics on the Calo blog.

References

1- Rosenbaum, M. & Leibel, R. L. (2010) ‘Adaptive thermogenesis in humans’, International Journal of Obesity, 34 (Suppl 1), pp. S47–S55. doi: 10.1038/ijo.2010.184

2- Stenman, L. K., Burcelin, R. & Lahtinen, S. (2016) ‘Establishing a causal link between gut microbes, body weight gain and glucose metabolism in humans – towards treatment with probiotics’, Beneficial Microbes, 7(1), pp. 11–22. doi: 10.3920/BM2015.0069

3- Zampino, M., Semba, R. D., Adelnia, F., Spencer, R. G., Fishbein, K. W., Schrack, J. A., Simonsick, E. M. & Ferrucci, L. (2020) ‘Greater Skeletal Muscle Oxidative Capacity Is Associated With Higher Resting Metabolic Rate: Results From the Baltimore Longitudinal Study of Aging’, The Journals of Gerontology: Series A Biological Sciences and Medical Sciences, 75(12), pp. 2262–2268. doi: 10.1093/gerona/glaa071.