What Is Metabolism?
Metabolism is a series of processes that control how your body creates and uses energy. It converts food and drinks into energy in your body, which you can use both when you're active and when you're resting. You need it for many basic functions, such as breathing and growing. Your metabolism uses calories and oxygen to make and release energy in a form the cells in all your organs and tissues can use.
Your metabolism affects how much of that energy your body uses up and how much it stores. You might hear people talk about metabolism when discussing health, weight, and nutrition. It can be low, high, slow, or fast.
You might think your metabolism, whether fast or slow, is something you're born with, passed down from your parents. Some people do seem like they've been born with a high metabolism and can eat whatever they want without gaining an ounce. But there are several things that you can control that affect your metabolism and your weight.
Anabolism vs. catabolism
Metabolism is broken down into two processes: anabolism and catabolism. Anabolism is the storing of energy, supporting new cells, and maintaining body tissues. Catabolism is the opposite, breaking down energy to move, heat, and fuel your body.
What Is Basal Metabolic Rate?
Your basal metabolic rate (BMR) is the amount of calories you need to keep your body working when you're resting. Your BMR gives your body the energy it needs for many basic functions that are happening all the time, without you thinking about it. For example, you need it to:
- Breathe air into your lungs
- Pump your blood
- Break down your food
- Grow
- Heal
- Make and control your hormone levels
- Keep your body warm
People can have really different BMRs. About 60%-70% of the energy your body uses goes toward your BMR. But your BMR may vary depending on:
- How much muscle you have
- How much fat you have
- How old you are
- How many calories you eat
- How active you are
Some people think your sex plays a role, but at least one study didn't find it to have any impact on BMR. Exercise might also change your BMR, but it's not easy to tell how. If you need to rest a lot, it may go down. If you run a lot and then stop, even that may cause your BMR to go down. Your BMR also can vary for lots of reasons that scientists and doctors don't understand.
Your BMR can also change. For example, if you try to lose weight and cut calories drastically, it will make your BMR go down. That's why it can seem like you'll lose weight fast at first and then you'll see weight loss slow down.
Fast metabolism vs. slow metabolism
If you have a "fast metabolism," it means that you burn lots of calories when you're just resting. If your metabolism is slow, your body can get by with less food or calories. But it might surprise you that fast vs. slow metabolism doesn't always relate to a person's weight in the way you'd expect. Many people who have fast metabolisms or BMRs can be overweight or have obesity. So, having a fast metabolism doesn't always mean you'll be thin. Your weight will depend on many other factors, such as how active you are, how much you eat, and what you eat.
Metabolism and Weight
It’s easy to blame problems with weight on metabolism. But maintaining your weight is a complex process that involves genetics, hormones, diet, lifestyle, sleep, physical activity, and stress.
A lack of activity combined with lower energy needs creates a slow metabolism. If you give your body too much energy in the form of calories, that energy has nowhere to go and is stored as fat.
Your metabolism is working to maintain your weight. You can’t change your routine for a few days and expect major changes. A balance of good habits will help your metabolism recognize a new ideal weight.
Factors That Influence Your Metabolism
Your metabolism depends on many different factors. Some of them you can change, but others you can't. These include:
Genes. How much energy your body needs is determined by a handful of genetic factors. Larger people have more muscle mass and usually need more calories. Men tend to have less body fat and more muscle mass, so they need more calories.
Age. A common myth is that age causes your metabolism to slow. But age isn’t the main problem. As you get older, you may not be as physically active, you may have less muscle mass, and your diet may not change to suit your body’s needs. All of these things lead to a slower metabolism.
Diet. There are no miracle foods, eating plans, or perfect diets to maintain your metabolism. But you can still improve your metabolism through your diet. A diet of good carbohydrates, a suitable amount of calories, and consistent meals will give your body the energy it needs.
One popular diet to improve metabolism is intermittent fasting. This involves eating during a set number of hours each day (often about 8 hours) and not eating for the rest of the time. Once your body exhausts the energy it took in, it starts using energy stored in your body’s fat. This may allow your body to get rid of any extra fuel it has stored.
Intermittent fasting can be helpful for weight loss, heart health, diabetes, and obesity. There are many plans, so it’s important to pick one that works with your health and needs. Talk with your doctor before trying it.
Sleep. Sleep helps regulate your glucose, or blood sugar. A lack of sleep causes your body to have trouble with glucose levels, leading to a lack of energy.
Good sleep habits don’t involve counting minutes and sleep aids. Make sure you’re getting good sleep by:
- Going to sleep and waking up at the same times every day
- Avoiding caffeine, nicotine, and long naps within a few hours before bed
- Avoiding blue light before bed, such as TVs, computers, and phones
Sleep is a great time for your body to burn extra energy. Boosting your metabolism through diet and exercise will also help your body burn more calories while at rest.
Exercise. An important piece of the puzzle is exercise. Moving your body uses the most energy and burns calories. Moving regularly, even a walk around the block, can boost your metabolism to help you use excess energy, burn fat, and improve your heart health.
Muscle-strengthening exercises are also important to make sure you have a healthy amount of muscle. More intense strengthening exercises will help reduce the signs of common metabolic diseases.
How to increase metabolism
Your metabolism is complex and won't change quickly or at will. If you want to increase your metabolism, consider talking to a doctor, dietitian, nutritionist, or other specialist about factors or habits you can change that may help you speed up your metabolism. Some things that may boost metabolism include:
- Exercising more
- Eating less fat and more complex carbs
- Planning your meals
- Eating at regular times
- Limiting alcohol and sugar
- Getting enough sleep
What Are Metabolic Disorders?
A metabolic disorder is a condition that gets in the way of one or more chemical reactions that are part of normal metabolism. You can have many different types of metabolic disorders. Most of them are rare. Some examples include:
- Phenylketonuria (PKU). In this condition, your body can't break down an amino acid called phenylalanine.
- Galactosemia. If you have this condition, you can't break down a sugar called galactose because of a problem with the enzymes you need to do it.
- Prader-Willi syndrome. Kids with this condition want to eat all the time and never feel like they're full. Doctors don't know exactly why this happens.
What is metabolic syndrome?
You may also have heard of something called metabolic syndrome. This isn't a specific condition. It's a group of things that can happen when your metabolism or lifestyle isn't healthy including:
- High blood pressure
- High blood sugar
- Too much fat around your waist or in your belly
- High cholesterol
- High triglycerides
Takeaways
Metabolism includes all the chemical processes your body needs to break down food and fuel you when you're active and when you're resting. While some aspects of metabolism depend on your genes, you can influence others by changing how you eat and how active you are. But having a fast or slow metabolism doesn't always mean you'll be thin or overweight.
Metabolism FAQs
- How do I increase my metabolism?
You can't change everything about your metabolism, but healthy habits may help you speed up your metabolism. Some things that can affect metabolism are how much fat or muscle you have, what and how much you eat, and how active you are. If you want to increase your metabolism to lose weight, ask your doctor what they recommend.
- What are the causes of slow metabolism?
Some people have a slower metabolism than others for lots of complex reasons. But your metabolism could also slow down if you suddenly decrease your activity level. Your age too could cause your metabolism to slow down, but this happens slowly. The reason isn't necessarily so much your age; it may have more to do with being less active or having less muscle.
- What are the two types of metabolism?
The two main types of metabolism are anabolism and catabolism. Anabolism involves building bigger molecules from smaller ones. Catabolism is the opposite. Your body breaks down bigger molecules into smaller ones.
