“Kenny, it’s a pleasure watching you eat,” my grandmother would often declare. “I don’t know where you put it all!” My mother would joke that, as a teenager, I had a hollow leg in which I stored all those calories. Friends now tell me that I’m lucky, that I have a “fast metabolism.”
Can you be gifted an efficient one at birth? Or be cursed with a slow metabolism that, like a rusty engine block, churns out more smoke than speed? Or can you craft one to your liking with proper fuel and maintenance?
The answer is as complex as the metabolism itself.
Clare Sullivan, a naturopathic doctor at Ottawa’s Somerset Health and Wellness Centre, says, “Your metabolism is basically what’s keeping you alive. It’s breaking down food; it’s giving you energy; it’s keeping all of your systems running. Your cells are then using that as fuel and pumping out energy that your body uses. So, it’s all of the systems working together to allow you to live.”
Your metabolism is the furnace in your steamship, distributing whatever gets thrown in the fire throughout your pipes and valves, propelling you along the river. The source of fuel is vital, but not everyone is born with access to the same class of vessel.
“People are born with certain genetics that determine their basal metabolic rate,“ says I. George Fantus, MD, Director of the Division of Endocrinology and Metabolism at the McGill University Health Centre.
“But … there are other factors ... disorders of the thyroid gland will regulate basal metabolic rate, because the thyroid hormone acts on various different tissues to change and regulate the genetic expression of certain receptors in those tissues,” Fantus adds.
“If your thyroid gland makes more hormones, your heart rate will speed up and your metabolism speeds up. Hypothyroidism is an autoimmune disease, but this time the antibodies actually destroy the thyroid gland, and you get the opposite: you get weight gain, you feel sluggish, and the metabolism is slow,” says Fantus.
Fantus explains that at a microscopic level, the metabolism is a broad area that also includes the macronutrients protein, carbohydrate, and fat. As well, at the molecular level, a lot of research is focusing on the hundreds and hundreds of species of gut flora in the bowel, and how they might affect our metabolism.
Keep track of your fuel intake with a calorie-counting app for a week or two (more than that can be daunting!). This will give you an idea of how many calories—and therefore how much energy—your food contains. This will help you make a link between exercise and weight management.
Maintaining a healthy gut begins with reaching for healthy food sources—rich sources of fuel for our furnace—explains Dasha Maslennikova, a kinesiologist and clinical director at Symmetrix Exercise and Rehab in Vancouver. “Having a healthy diet is hugely important for your metabolism.”
Maslennikova suggests a different metaphor: if you fuel a campfire with paper versus wood, you get a quick flame that quickly burns itself out. Think of the paper as processed foods and refined sugars, and the wood as complex carbohydrates. A daily diet of the former “really affects your metabolism and your insulin differently than if you were eating whole foods” including complex carbohydrates.
Most experts I spoke with recommended two diets to maintain proper nutrition: the Mediterranean diet and the DASH (dietary approaches to stop hypertension) diet. Both plans recommend lean meats; poultry and fish; and proper amounts of fruits, vegetables, and sources of healthy oils and plant proteins.
Whenever making major dietary changes, it’s critical that you ensure you aren’t accidentally cutting out key nutrients for your body’s functioning. Don’t be afraid to supplement!
B vitamins enable brain functions and help promote skin, hair, and nail health.
Calcium regulates blood flow and strengthens both bones and muscles.
Iron is used when creating hemoglobin, allowing blood cells to carry oxygen.
Magnesium is an ion used for transmitting nerve signals to and from the brain.
Vitamin D makes other nutrients more bioavailable and can be absorbed through food as well as from the sun.
Once our ship has the proper fuel, using the engine is vital to keeping it in good working order. When it comes to your health, think of this as exercise. “People who exercise raise their metabolic rate, so if you keep in shape, your basal metabolic rate will be higher,” says Fantus.
What is most important about exercise is wanting to exercise. A recent study reported in Frontiers in Psychology drew a direct link between how much people enjoyed their exercise and how likely they were to continue exercising.
“If you like walking, walk. If you like playing tennis, play tennis. If you like riding your bike, ride your bike,” says Maslennikova. “And if you’re already doing that and you need more, what you would want to do is resistance training.”
“If you’re exercising in a way to build muscle, you’re … increasing your resting metabolism, because you have more muscle mass. So over time, there’s a positive feedback loop: the more you exercise, the more energy you burn; the more muscle you have, the more energy you burn.”
Finally, once your day is done—and your ship has returned to port—proper rest is absolutely vital.
Sullivan explains that “… sleep is super important. It’s a time when our bodies are clearing out toxins from the day. It allows our bodies to rest and recuperate, rebuild muscle, and consolidate memory.”
Our bodies do this important work overnight so that we wake up the next morning ready to go again. Sullivan adds that good sleep benefits weight management. But if you’re stressed, this can make it harder to sleep well, which in turn can make it harder to lose weight; stress elevates cortisol levels that can lead to weight gain, thus impacting our metabolic and cardiovascular health.
For people who may have trouble gearing down after their day—for instance those of us who may have a hollow leg but a hassled brain—Sullivan recommends meditation, even if it’s just three minutes per day.
“Eat well, exercise, and get plenty of rest.” It’s both proper and maddening advice. But what if, even incrementally, you tweaked your metabolism to work for you? What if you had the power to remove a few reeds from your path in the river, to slow the wind, and to turn your ship so it flowed with the tide. Your engine wouldn’t have to work as hard, and it would increase its lifespan. And who doesn’t want more time on the water?
This article was originally published in the February 2025 issue of alive magazine.