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Home arrow Nutrition arrow Healthy Eating arrow 11 Signs of a Fast Metabolism: What You Should Know

11 Signs of a Fast Metabolism: What You Should Know

Written by Edibel Quintero, RD
Fact checked by Rosmy Barrios, MD
Last update: January 16, 2024
7 min read 3026 Views 0 Comments
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Uncovering the hidden signs of speedy digestion

11 Signs of a Fast Metabolism

A fast metabolism can be a good or bad thing for people. 

Someone with a fast metabolic process may find it frustrating to gain weight. This is because their body burns calories at a quicker rate. Not everyone feels this way, but it can prove to be challenging when you constantly need to eat more throughout the day.

Having a slow metabolism can cause similar issues, except people would struggle to keep the weight off. There are plenty of signs that point to having a fast or slow metabolism. From increased heart rate to frequent urination, you’re bound to notice at least one common sign.

Are you curious to learn more about your metabolism? Do you experience some strange symptoms? If yes, then keep reading to learn more about a fast metabolic rate.

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11 Signs of a Fast Metabolism You Should Know About

A faster metabolism doesn’t always do good things for your body. It can make you sweat or more hungry after big meals. Your basal metabolic rate [1] determines how much energy your body burns while at rest. The higher it is, the more likely you have a faster metabolism. 

Let’s take a look at the 11 common signs of a fast metabolism: 

#1 It’s impossible to gain weight

Those with fast metabolism may find it hard to build body fat. Their basal metabolic rate (BMR) is much higher due to how many calories their body needs to function properly. Not gaining weight may sound like a dream, but it’s tough for those wanting to bulk for the gym.

People usually increase their calorie intake to put on weight. The recommended daily calorie intake for women is 2,000 and 2,500 for men [2]. This figure will depend on their activity level, gender, and age. If you have a fast metabolism, you might require 2,500 calories just to gain a little extra fat. 

This can be especially annoying if you like to burn at least 500 calories from high-intensity workouts. The more calories you burn during exercise, the more calories you need to eat. So, you might end up eating around 3,000 calories, which is a lot to keep up with on a regular diet.

#2 Fast heart rate

A fast metabolism could lead to a fast heart rate during normal daily activities and even rest.

Since you might be eating more to gain weight, your body needs to work harder to digest food properly. This results in your heart rate increasing to help your metabolism. 

However, other health conditions may be the cause of this symptom. Hyperthyroidism (overactive thyroid) [3] happens when your thyroid gland produces too many thyroxine hormones. This accelerates your metabolism and encourages the body to gain or lose weight.

#3 It’s difficult to maintain weight

Maintaining your weight can be more challenging than gaining it. A fast metabolism will often burn through fat storage if you haven’t eaten enough during the day. This may result in dramatic weight loss that prevents you from building more muscle mass at the gym. 

Try to eat more calories when maintaining a healthy weight, as the number of calories you consume might also fuel you with more energy. A fast metabolism shouldn’t hold you back from achieving your fitness goals. Consider keeping a food journal to track your calorie intake. 

#4 Increased appetite

A faster metabolism means you have to eat more to feel full. 

Your body will release hunger hormones like leptin, ghrelin, and insulin [4] to warn you that your metabolism has already burned those calories. Make sure to eat nutritious meals that have bigger portions to fuel your gut.

#5 A low percentage of body fat

People with fast metabolism are more likely to have a lower body fat percentage. Their quick metabolic reactions burn through energy sources before fat can be stored on body parts. Those with a slower metabolism could easily store extra fat around the stomach, face, and thighs.

If you also perform vigorous physical activity, you might be burning calories from muscles or essential fats. This is why you need to eat more than what your fast metabolism is working through. A very low-fat percentage can lead to future health problems.

#6 Irregular menstrual cycle

Your resting metabolic rate can increase for a few days during ovulation. 

This might cause your periods to be early or late, depending on how quick your metabolism is. A fast metabolism can also trigger hormonal changes that disrupt your menstrual cycle completely. 

Physical activity is said to help balance the hormones in your body [5]. You can perform regular exercise before, during, or after menstruation. The thyroid gland is more likely to regulate the period changes. Just remember to take it easy and slow when performing intense workouts.

#7 Excessive sweating 

People with a fast metabolism usually produce too much thyroxine – a chemical that helps regulate the metabolism. 

When your body burns through fat quickly, it causes you to sweat considerable amounts. This may be uncomfortable and hard to manage sometimes. 

You might also experience a racing heartbeat, anxiety, nervousness, shaky hands, weight loss, and disrupted sleep. These are very common symptoms of a fast metabolism. Excess energy usually triggers chemical processes that are responsible for sweating.

#8 You have high energy levels all day  

A fast metabolism may cause you to eat more throughout the day. This fuel will turn into energy that keeps you alert. 

You should avoid drinking caffeinated beverages when feeling wide awake. If you consume more energy, you might not be able to sleep during the night. 

#9 You are peeing frequently

Frequent urination is very common for someone with a fast metabolism [6]. Not everyone will experience it, but physical activity mixed with a rapid metabolism can stir movement in your lower abdomen. 

However, you might also be drinking too many fluids. A gallon of water a day is healthy for you, but even drinking 8–12 cups is still great. Going over this amount could lead to water poisoning that affects your brain function and central nervous system. 

#10 Slightly higher body temperature

A fast metabolism could increase your body temperature due to how many calories you’re burning. You may feel warmer when eating, sleeping, exercising, and breathing. This is when your metabolism is working the hardest to burn calories throughout the day. 

#11 Irritability

Feeling annoyed is a natural occurrence for someone with a fast metabolism. Hyperthyroidism is usually the cause of such irritable symptoms. 

Sleep disturbances will also make you feel agitated the next day, so talk to a doctor if you keep experiencing these emotional waves. 

What Is a Fast Metabolism?

A fast metabolism means your body burns more calories. 

People usually measure their basal metabolic rate (BMR) when determining how fast their metabolism works. If you have a high BMR, then your body requires extra calories to properly function throughout the day. You can use the below formula to estimate yours. 

Women: 655 + (4.35 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)

Men: 66 + (6.23 x weight in pounds) + (12.7 x height in inches) – (6.8 x age in years) 

For example, a 23-year-old woman is 67 inches tall and weighs 132 pounds. The equation would be 655 + 574.2 + 314.9 108.1 = 1,436 calories. This is the amount she needs to function when completing daily activities, such as resting, breathing, and sleeping.

How to Know if You Have a Fast Metabolism?

You will most likely struggle with maintaining or gaining weight. 

A fast metabolism burns through calories quickly without storing fat between your organs. Therefore, you may struggle to increase your fat percentage over time. Increasing your daily calories could help you build up the necessary fat without becoming too unhealthy. 

You might find that high-intensity interval training (HIIT) actually makes you shed weight quickly. This is why you need to eat more before and after working out. If you feel tired, weak, or lightheaded, this is a sign that your body requires extra energy.

Why Is My Metabolism So Fast?

Your metabolism depends on genetic and physical factors.

People with larger muscle mass usually have a fast metabolism. Age, fitness level, and gender can also contribute to the metabolic rate. If you want to increase your metabolism, consider performing more physical activity to improve the calorie-burning process. 

A strong metabolism also runs in your family’s genetics. If your parents have a high metabolic rate, you’ll most likely share the same BMR. Just remember that your metabolism will slow down with age since your body is getting naturally weaker and more fragile.

A Word From a Personal Trainer

A fast metabolism can depend on your muscle mass, age, gender, and workout routine. Not everyone shares the same metabolic process. Some people may have a really slow metabolism that prevents them from losing weight. It all comes down to your genetics and physical factors.

Sweating, irregular hormone levels, high energy, and frequent urination are just a few common signs of a fast metabolism. You might experience all of these symptoms, but if you do, they are completely normal and represent how fast your metabolism burns calories.

If you want to strengthen your metabolism, complete strength training exercises that help build muscle mass. This will eventually improve your body’s natural digestion process.

Just find a workout and diet plan that works for your metabolism.


You shouldn’t worry about having a fast metabolism since it mainly boils down to genetics and factors you can’t change. 

Focus more on your overall health when eating extra calories or performing intense cardio-based workouts. It’s important to take care of your body’s functions.


  1. Hulbert A. J, Else P.L. Basal metabolic rate: history, composition, regulation, and usefulness. 2004.
  2. U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th Edition.
  3. National Institute of Diabetes and Digestive and Kidney Diseases [NIDDK]. Hyperthyroidism (Overactive Thyroid).
  4. Yeung A.Y., Tadi P. Physiology, Obesity Neurohormonal Appetite And Satiety Control. Updated 2023 Jan
  5. Samadi, Z., Taghian, F., Valiani, M. The effects of 8 weeks of regular aerobic exercise on the symptoms of premenstrual syndrome in non-athlete girls. Iranian Journal of Nursing and Midwifery Research. 2013.
  6. Hsu Li-Nei, Hu Ju-Chuan, Chen Po-Yen, Lee Wei-Chia, Chuang Yao-Chi. Metabolic Syndrome and Overactive Bladder Syndrome May Share Common Pathophysiologies. 2022 Aug.
Written by Edibel Quintero, RD
Edibel Quintero is a medical doctor who graduated in 2013 from the University of Zulia and has been working in her profession since then. She specializes in obesity and nutrition, physical rehabilitation, sports massage and post-operative rehabilitation. Edibel’s goal is to help people live healthier lives by educating them about food, exercise, mental wellness and other lifestyle choices that can improve their quality of life.
The article was fact checked by Rosmy Barrios, MD
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Written by Edibel Quintero, RD
Fact checked by Rosmy Barrios, MD
Last update: January 16, 2024
7 min read 3026 Views 0 Comments

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