Most people first encounter the term ‘metabolism’ when they start a diet or exercise program to lose weight. The understanding is that your body’s metabolism is kind of like a train engine, and the faster it moves, the quicker you lose weight.
Is it any wonder then that many of us are always looking for ways to speed up our metabolism?
What is metabolism
Metabolism is a 24/7, non-stop bodily process that involves several biochemical reactions.
The primary purpose of the human metabolic system is to convert the food we eat into the fuel we need to function. But your metabolism performs many other jobs, too, such as growing new cells for tissue regeneration, keeping you warm, and helping your muscles move.
Anabolic and catabolic
Your metabolism is made up of two distinct processes: anabolic and catabolic.
- Anabolism: The anabolic, or constructive, process is your body’s manufacture and repair system. If your body were indeed a temple, the anabolic system would be the bricks, cement, wiring, plumbing, etc. needed to physically build the structure.
During the anabolic process, tiny molecules of protein, carbohydrates, and fat that have been extracted from digested food via catabolism (more on that below) are fitted together into larger, more complex arrangements to make muscle tissue, organ tissue, nerves, veins, bones, and so on.
- Catabolism: The catabolic, or destructive, process can be thought of as happening concurrently on either side of the anabolic process. First, digestive catabolism extracts from digested food the protein, carbohydrate, and fat molecules needed by the anabolic process to create the building blocks of your-body-the-temple.
Then, after your-body-the-temple has been built, further catabolic processes smash the walls, rip out the wiring, and dismantle the pipes. These are ‘burned up’ to generate the energy your body needs to perform all its various activities.
What is resting metabolic rate
Resting metabolic rate is the (generally quite low) speed at which your body uses up energy when you’re not doing anything too active, or are just going about your day doing low-effort things like lying on the couch watching television, making breakfast, or brushing your teeth.
What part of the body controls metabolism
The human body produces, releases, and regulates several different hormones. This entire process is managed by the endocrine system.
Among the many hormone-producing glands in the endocrine system are the pituitary gland (for physical growth), pancreas (for insulin), pineal (for melatonin to help you sleep), and the thyroid gland.
Your metabolism is controlled by the thyroid gland. This is located midway down your throat, just in front of your windpipe. The thyroid gland releases two hormones, thyroxine (also known as T4) and triiodothyronine (T3), into your bloodstream to regulate heart rate, body temperature, energy levels, and more.
Metabolic speeds by age
Your metabolism starts out pretty fast, and slows down the older you get.
Babies between 9 and 15 months of age have the fastest metabolism because their bodies are continuously and rapidly creating large amounts of new tissue. Their anabolic, or construction, process is in overdrive, and the catabolic processes must keep up both the supply of building material and the fuel that is burned up for energy.
As children grow older, their metabolic rate fluctuates, speeding up during growth spurts to meet energy requirements.
By the age of 20, the average person’s metabolic rate tends to stabilize. It remains fairly consistent until the age of 60, and then starts slowing down.
Why does metabolism slow down with age
A big reason why metabolism slows down with age is that you do not have the same amount of muscle mass as before.
Muscles use much more energy to function than fatty tissue does. When you have more muscle and less fatty tissue, your metabolism has to work faster to both create and use up muscle tissue.
Sarcopenia is the natural process of age-related muscle loss. It usually begins around the age of 30 years, and you can lose anywhere from 3% to 5% of muscle every year from then on. This natural loss of muscle leaves your metabolism with no choice but to slow down.
Most people also become less physically active as they grow older. A sedentary lifestyle, muscular atrophy, hormonal changes, and a diet composed largely of unhealthy, calorie-dense foods adds to the loss of muscle mass and gaining of fat tissue. When there’s more fat on your bones than muscle, your metabolism slows down.
Ways to increase metabolism
You might be able to coax your metabolic speed up by paying attention to two important factors:
- Food intake and energy usage
- The thyroid gland
Food intake and energy usage
An adequate amount of muscle tissue is necessary to keep metabolism at a good speed. Muscle tissue is made of protein, so make sure a substantial chunk of your diet consists of protein. Foods high in protein include lean meat, fish, eggs, dairy products, nuts, seeds, legumes, and tofu.
Any kind of exercise is better than none, but strength-training or lifting weights to boost muscle mass is especially effective in speeding up your metabolic rate.
Thyroid gland
Aging also changes how your thyroid gland works. After years of diligently doing its job, your thyroid gland many now:
- Take too long to produce T3 and T4 hormones.
- Have shrunk. This is called thyroid atrophy. Because the thyroid gland is smaller than it ideally should be, it may not produce hormones in the quantities your body needs.
- Have developed an autoimmune condition like Hashimoto’s disease.
A thyroid gland that doesn’t work properly leads to the person feeling tired, sluggish, and sensitive to cold temperatures. You may also gain weight and have trouble losing weight. Additionally, your hair might fall out and become thin, and you could also be at higher risk of depression.
Metabolism and the thermogenic effect of drinking water
The thermogenic effect is when your body’s core temperature falls after drinking water, especially cool or cold water. To counter this drop, your metabolic rate sprints to warm your body and bring your core temperature back up.
Studies have shown that drinking just 2 cups of cool water may speed your metabolism up to 30% faster.
Are there any supplements to increase metabolism
Most health experts are of the opinion that so-called ‘fat burners’ or ‘metabolism boosters’ don’t have any significant effect on your metabolism. However, there are certain vitamins and minerals that should ideally be part of your diet to maintain a reasonable metabolic rate for your age.
- Vitamin D: Your best source of Vitamin D is sunlight. Experts recommend that adults aged 65 years and above get at least 15 minutes of sunlight a day, three times a week, but do talk to your doctor first to know how much sunbathing is safe for you.
- Iodine: Iodine is essential for good thyroid function. Your body does not produce its own iodine, so you have to get it either through food or supplements. Eggs and dairy products contain some iodine, and the best sources are foods from the sea, especially seaweed. Iron supplements or iron-rich foods should be taken alongside as iron helps your body absorb iodine better.
- Magnesium: This mineral is necessary for hundreds of biochemical reactions in your body. Your best food sources for magnesium are whole grains, spinach and other dark green leafy vegetables, nuts, and good dark chocolate.
You can take a multivitamin or individual supplements to fill in nutritional gaps, but always check with your care provider first to make sure the supplements are right for you.