Medically reviewed on October 20, 2023 by Rosanna Sutherby, PharmD. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.
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Metabolism is the chemical process in your body that turns the food you consume into the energy needed to run the functions that keep you alive. The number of calories your body burns for fuel largely determines your metabolic rate—and some people are known to have a faster metabolism compared to others (meaning their bodies in a resting condition need to burn more calories in a given time frame). 
So you may be wondering whether you have a fast metabolism—and if there are any signs that could clue you into this possibility.
Here we’ll dive deeper into the possible signs of a fast metabolism, plus provide answers to other questions people commonly have about “fast metabolism”—so continue reading.
Check your levels of three key hormones that affect metabolism and weight (cortisol, testosterone, and thyroid-stimulating hormone or TSH) with the easy-to-use, at-home Metabolism Test. Note that this test does not give you a measurement of your metabolic rate.
Your metabolism is a complex process that helps to maintain homeostasis. To understand how your metabolism works, it’s critical to understand its three components :
Your BMR refers to how much energy (calories) your body needs to maintain its baseline physiological functions when at rest.  In other words, if you were to stay in bed all day, without moving, your body would still require energy to breathe, distribute blood, and repair tissues, among other things.
For men, the average BMR sits at 7,100 kilojoules (kJ) a day, while women average around 5,900 kJ daily. 
A significant factor in BMR is the amount of lean muscle mass you have on your body since maintaining muscle mass requires a lot of energy expenditure. As such, a higher level of muscle mass will lend itself to a higher BMR. 
Your metabolism, and your resting and basal metabolic rate, is significantly influenced by genetics. That being said, a faster metabolism (in terms of resting metabolic rate) may be promoted through strength training exercise. 
Several factors are correlated with metabolic rate, including :
Hormonal imbalances can also impact your metabolic rate since hormones help facilitate the digestion and absorption of nutrients. More specifically, thyroid disorders can either increase or decrease your metabolism. 
Namely, hyperthyroidism (in which large amounts of the thyroid hormone are produced) can boost your metabolism. Conversely, hypothyroidism, characterized by an underactive thyroid, will slow your metabolism since not enough of the hormone is entering your system. 
The thermic effect of food, or thermogenesis, refers to the amount of energy your body uses to not only digest the foods you consume but also absorb, transport, and store their nutrients.  Fats, like red meat, whole milk, and eggs, will only raise your BMR up to 5%, while carbohydrates—found in breads, vegetables, and pastas—can increase it anywhere from 5 to 10%. 
Proteins, however, are the most effective at raising your BMR—up to 20 to 30%. 
The third component of your metabolism is the energy you burn during exercise. The amount of energy you burn, however, will depend on the intensity of the workout: lower-intensity workouts require less energy, while higher-intensity workouts or those that last several hours will require more energy. 
Your energy used during physical activity is the only energy expenditure that you can control. When you exercise, your body uses the calories you consume to fuel its movements. Regular exercise can increase your lean muscle mass and promote more energy usage from day to day, increasing your metabolism over time. 
That said, several other factors may contribute to a temporarily faster metabolism. These include :
What is a fast metabolism? While it’s hard to pinpoint the exact signs of a fast metabolism, there are possible indicators that may suggest your metabolism works at a faster rate.
Fast metabolism symptoms or signs of high metabolism may include a decrease in body weight and acute or chronic stress. [4,5]
It’s important to note that these high metabolism symptoms are very often caused by other factors or serious health issues that don’t have to do with one’s metabolic rate—so be sure to consult with your healthcare provider if you’re experiencing any of the above.
Also, contrary to some beliefs, a faster metabolism does not necessarily mean that you’re thin or experience difficulty gaining weight. Some studies have found that people who are overweight and obese have fast metabolisms since their bodies require more energy to function. A fast metabolism simply means that you have a higher BMR. 
Experiencing changes in your energy levels and aren’t sure why? The Everlywell at-home Metabolism Test lets you check 3 key hormones commonly associated with fast or slow metabolism and weight to help narrow down possible causes and determine whether abnormal hormone levels may be affecting your metabolism. Note that this test does not give you a measurement of your metabolic rate.
Having a high basal and resting metabolic rate means that your body naturally burns more calories in a state of rest than someone with a lower metabolic rate. This means that the faster your metabolism is, the more calories your body needs. 
While having a fast metabolic rate is not necessarily good or bad in terms of health, making sure you take in enough calories to sustain yourself and nourish your body is important—while also striving not to take in too many calories, which can lead to an energy imbalance or weight gain.
There is no clear answer for how long it takes to speed up your metabolism if you don’t have a higher metabolic rate genetically. Everybody is different and lifestyle, eating habits, and other factors play a role in how your metabolic rate may change over time.
That being said, here are a few, simple lifestyle changes that may help speed up metabolism over time:
Learn your levels of 3 key hormones (cortisol, testosterone, and thyroid-stimulating hormone or TSH) that affect metabolism and weight with the Everlywell at-home Metabolism Test. This at-home lab test lets you easily collect your sample from the comfort of your home, send it to a CLIA-certified lab for testing using the prepaid mailer provided in the kit, and get digital results in just a few days. The test can help indicate if abnormal hormone levels may be interfering with your weight gain or weight loss goals. Note that this test does not give you a measurement of your metabolic rate.