What Increases and Decreases Metabolism? Your Guide to Metabolic Health

November 18, 2025 •

5 min read

Up to 70% of the calories you burn daily are used for your body's basic functions at rest, known as your basal metabolic rate (BMR). Understanding what increases and decreases metabolism is key to managing your energy and weight effectively by making informed lifestyle choices.

Quick Summary

This article explores the key factors influencing your metabolic rate, including age, muscle mass, genetics, diet, and sleep. It covers the science behind how lifestyle choices can increase or decrease your body's energy expenditure and affect overall health.

Key Points

Muscle Mass: A higher proportion of muscle mass, gained through strength training, directly increases your resting metabolic rate (RMR) because muscle is more metabolically active than fat.
Exercise Intensity: High-Intensity Interval Training (HIIT) provides a temporary metabolic boost that continues long after the workout is over, a phenomenon known as EPOC.
Dietary Protein: Consuming adequate protein boosts your metabolism through the thermic effect of food (TEF) and helps preserve muscle mass, which is key for a higher metabolic rate.
Sleep Deprivation: Insufficient sleep can decrease metabolic rate and disrupt appetite-regulating hormones, increasing the risk of weight gain.
Extreme Dieting: Severely restricting calories slows down your metabolism as the body tries to conserve energy, making long-term weight loss challenging and potentially causing metabolic adaptation.
Aging: While metabolism gradually slows with age, this is primarily due to a decline in muscle mass and reduced activity levels, both of which can be counteracted with exercise.
Hydration: Drinking enough water, especially cold water, provides a small and temporary boost to your metabolic rate and is essential for all metabolic processes.

Understanding the Basics of Metabolism

Metabolism is the intricate set of chemical reactions occurring within your body's cells that convert food and drink into energy. This energy fuels every bodily function, from breathing and blood circulation to cell repair. Your metabolic rate, or the speed at which this process occurs, is influenced by a combination of genetics and lifestyle. A person's metabolic rate is not a fixed number and can fluctuate based on several factors, both controllable and uncontrollable.

The Components of Energy Expenditure

Your total energy expenditure comprises three main components:

Basal Metabolic Rate (BMR): This is the energy your body needs to maintain basic, life-sustaining functions while at complete rest, accounting for the largest portion of daily calorie burn.
Thermic Effect of Food (TEF): This is the energy expended to digest, absorb, and process the nutrients from your food.
Thermic Effect of Activity (TEA): This includes the energy used during both planned exercise and non-exercise activity thermogenesis (NEAT), such as fidgeting and walking.

Factors That Increase Metabolism

Several lifestyle and biological factors can positively influence your metabolic rate:

Building Muscle Mass: Muscle tissue is significantly more metabolically active than fat tissue, meaning it burns more calories at rest. Regular strength training is one of the most effective ways to build and maintain lean muscle, which in turn boosts your BMR.
High-Intensity Interval Training (HIIT): This form of exercise, which involves short bursts of intense activity followed by brief recovery periods, has been shown to significantly elevate metabolic rate even after the workout is finished, a phenomenon known as Excess Post-exercise Oxygen Consumption (EPOC).
Consuming Enough Protein: Your body uses more energy to digest protein compared to carbohydrates or fat. This thermic effect of food (TEF) means a higher protein intake can slightly increase your metabolic rate. Additionally, adequate protein is crucial for muscle repair and preventing muscle loss during weight management.
Staying Hydrated: Drinking enough water can briefly boost your metabolism. Drinking cold water, in particular, requires your body to expend extra energy to warm it to body temperature. Staying properly hydrated also ensures all metabolic processes function efficiently.
Drinking Coffee and Green Tea: The caffeine in coffee is a stimulant that can temporarily increase metabolic rate. Green tea contains catechins in addition to caffeine, which may also contribute to a metabolic boost.

Factors That Decrease Metabolism

Conversely, certain factors and habits can lead to a slower metabolic rate:

Aging: While not as dramatic as previously thought, metabolism does slightly decline after age 60, largely due to the natural loss of muscle mass (sarcopenia) that occurs over time. A sedentary lifestyle often exacerbates this decline.
Extreme Calorie Restriction: Drastically cutting calories sends the body into "starvation mode," prompting it to conserve energy and burn fewer calories. This can lead to a significant and lasting drop in BMR, making future weight loss more difficult.
Lack of Sleep: Chronic sleep deprivation can disrupt hormones that regulate appetite (ghrelin and leptin) and slow down your metabolic rate, affecting how your body processes glucose and fat. Aiming for 7-9 hours per night is vital for metabolic health.
Low Protein Intake: A diet low in protein results in a smaller thermic effect of food. Insufficient protein can also lead to a loss of muscle mass, further decreasing your metabolic rate over time.
Sedentary Lifestyle: Prolonged periods of sitting and lack of regular physical activity directly reduce the energy you expend daily, lowering your overall metabolic rate.
Medical Conditions: Hormonal imbalances, such as hypothyroidism (an underactive thyroid), can significantly slow down metabolism. Certain genetic and metabolic disorders can also play a role.

Comparison of Factors Affecting Metabolism


Factor	Effect on Metabolism	Impact Level	Controllable?
Muscle Mass	Increases	High	Yes, through strength training
Age	Decreases	Medium (gradual)	No, but effects can be mitigated
Dietary Protein	Increases	Low to Medium	Yes, by adjusting diet
Sleep Deprivation	Decreases	High	Yes, by improving sleep hygiene
Genetics	Varies (Predisposition)	High (innate)	No
Physical Activity	Increases	High	Yes, by being active
Extreme Dieting	Decreases	High	Yes, by avoiding crash diets
Thyroid Hormones	Varies (Disorder)	High (significant)	No, requires medical management

Debunking Common Metabolism Myths

Many misconceptions surround metabolism, particularly concerning weight management. One persistent myth is that metabolism slows dramatically in middle age, inevitably causing weight gain. A 2021 study in Science challenged this, finding that metabolic rates remain fairly stable between the ages of 20 and 60. The weight gain often attributed to age is more likely the result of decreased physical activity and the associated loss of muscle mass.

Another myth is that certain 'miracle' foods can drastically increase metabolism. While some foods have a small thermic effect, relying solely on them without considering overall dietary balance and exercise is ineffective. The best approach is a holistic one that combines a nutritious diet with a regular exercise routine.

Can you "damage" your metabolism permanently?

The concept of a "permanently damaged" metabolism is misleading, but the effects of prolonged metabolic suppression are real and can be persistent. Years of yo-yo dieting or eating disorders can trigger a protective metabolic slowdown that can take a long time to reverse, even after normal eating resumes. However, by consistently applying healthy lifestyle changes—including adequate nutrition, strength training, and proper sleep—it is possible to restore and improve metabolic function over time. The key is consistency and patience, rather than seeking quick fixes that are often unsustainable.

Conclusion: Taking Control of Your Metabolic Health

While factors like genetics and age are largely beyond your control, your metabolism is not a completely fixed variable. Lifestyle choices significantly influence your metabolic rate and energy expenditure. Building and maintaining muscle mass through regular strength and high-intensity training, consuming a balanced diet rich in protein, prioritizing consistent sleep, and staying hydrated are all powerful, evidence-based strategies for promoting a healthy metabolism. By focusing on these sustainable habits, you can take meaningful steps toward better metabolic health and more effective weight management. Your body is a complex system, and supporting its processes with consistent, positive behaviors is the most reliable path to a healthier future.

Frequently Asked Questions

The most significant factor is body composition, specifically the ratio of muscle to fat. Muscle tissue is more metabolically active, so individuals with more muscle mass naturally have a higher basal metabolic rate (BMR).

Recent research suggests that while metabolism does decline, it's not a dramatic slowdown in middle age as once believed. The decline is more noticeable after age 60 and is largely linked to the gradual loss of muscle mass that occurs over time.

While certain foods, like protein-rich items, spices, and caffeine, have a small thermic effect that temporarily increases calorie burning, no single food can drastically speed up your metabolism. A balanced diet is more important than focusing on individual 'superfoods'.

When you drastically cut calories, your body perceives it as starvation and slows down your metabolism to conserve energy. This adaptive response can make it harder to lose weight and easier to regain it after the diet ends.

Inadequate sleep disrupts the hormones that control appetite and satiety, namely ghrelin and leptin. It can also negatively affect how your body metabolizes glucose and fat, potentially slowing down your metabolic rate.

Yes, it is possible to improve a slow metabolism, particularly one affected by chronic dieting. Focus on increasing lean muscle mass with strength training, eating enough calories from nutritious sources, and prioritizing consistent sleep and activity.

Yes, genetics play a significant role in determining your inherent metabolic rate. However, lifestyle factors like diet and exercise have a major impact on overall metabolic health and can help optimize your body's energy use, regardless of genetics.

Both are crucial. Exercise, especially strength and HIIT, directly increases energy expenditure and builds muscle, boosting your BMR. Diet influences the thermic effect of food and provides the fuel needed for exercise and recovery. A combination of both is most effective.