How to Increase Your Metabolism to Burn More Fat?

The human body contains around 37 trillion cells. Each is like a little factory, busily producing all the things that keep us alive, from enzymes to neurotransmitters to hormones.

The calories we consume provide the energy that fuels this work. Every day, our cells burn enough energy to bring eight gallons of ice water to a roiling boil.

Energy, then, is the currency of life. But the system regulating energy consumption – metabolism – is often misunderstood. It’s time to change that.

Literally, what you eat makes you who you are

In 1859, the French scientist Louis Pasteur made a revolutionary broth. What made it so special? Well, first, Pasteur realized that boiling the soup killed any germs that might be in the liquid. And second, he found that keeping it in an airtight flask prevented bugs and dirt from entering. This two-step system prevented the soup from spoiling – a revolutionary discovery.

This process came to be known as pasteurization, named after Pasteur himself. The experiment wasn’t just a practical triumph, though. It was also the final nail in the coffin of a theory as old as Aristotle – a theory known as spontaneous generation.

Spontaneous generation tried to explain phenomena like the sudden emergence of maggots on rotting meat. Where did these maggots come from? Before the invention of powerful microscopes, it was hard to answer that question.

From antiquity to the Middle Ages and well beyond, people argued they came from nowhere – that is, that they spontaneously generated from inanimate objects like meat.

It’s easy to scoff at such an outdated notion, but a century of research into metabolism has shown that the truth is even stranger.

Today, we know that maggots don’t emerge from inert material. But look closely at a maggot-laying fly. What does it do? Essentially, it’s a small machine that transforms putrid protein into baby flies. Put differently, it spontaneously assembles its own and its offsprings’ bodies out of water, air, and the food it consumes.

Like flies, humans are also spontaneous-generation machines. Every ounce of bone and pint of blood, every fingernail, eyelash, and strand of hair, is made out of the things we eat. Inanimate matter, it turns out, does generate life.

How does this uncanny transformation occur? The answer is metabolism – the way our bodies burn energy. Let’s break that down.

The body is made up of thousands of different, interacting molecules. These include enzymes, hormones, neurotransmitters, DNA, and more. Very few of them arrive in the body in usable form through our diets, however. Before they can be put to use, they have to be converted.

This is the work of cells. A cell’s job is to pull useful molecules circulating in the bloodstream in through its membrane and then convert those molecules into something else. Take ovary cells. They pull cholesterol molecules inside, convert them, and then push the end-product – estrogen, a hormone that affects the whole body – back into the bloodstream.

The work of these cells is what keeps us alive. But it requires energy – lots of it. Metabolism is the body’s life-preserving furnace, “burning” the food we eat and unlocking its energy for this purpose.

A measure of metabolism is how much energy the body expends

Cells do work, and this requires energy. But how are we defining these terms?

In fact, the two concepts are interchangeable. In physics, work is a technical term. And, since work and energy are measured using the same units, we can use them interchangeably. In other words, work is energy.

When you throw a baseball, for example, you’re doing work – that’s what accelerates the ball. At the moment the ball leaves your hand, the energy you exerted throwing it is converted into kinetic energy or, in other words, the energy of its movement through the air.

Another everyday example of energy is heat. When you warm milk in a microwave, for instance, the temperature increase tells you how much electromagnetic energy the milk has captured.

Energy consumed is always equal to work done and heat gained. This is a fundamental law of physics, so, naturally, it also governs the human body.

Energy can be stored in things that have the potential to do work or create heat.

Gasoline in a fuel tank is a good example. So is a stretched rubber band, which has a form of potential energy called “strain energy.” Meanwhile, a heavy plant pot that’s precariously balancing on a window sill and could come crashing down at any moment has potential kinetic energy.

At a molecular level, the bonds holding molecules together store chemical energy. This energy can be converted. But it can’t be lost. When a strained rubber band is released, the molecular bonds snap apart, releasing that energy into the surrounding environment. It’s a natural law: energy is never lost, only converted.

Explosions are spectacular examples of this law. Take nitroglycerin. When you detonate this volatile liquid, its molecular bonds break apart into nitrogen, carbon monoxide, oxygen, and water, releasing energy. How much? Well, if the energy stored in a pound of nitroglycerin is converted into heat, it would instantly vaporize a human – that’s what powerful bombs do. If it’s converted into kinetic energy, on the other hand, it could launch a 165-pound adult two and a half miles into the sky.

But what does this have to do with metabolism?

Well, if energy and work are interchangeable, the work our cells do and the energy they consume are two ways of measuring the same thing. “Metabolism” is another way of saying “energy expenditure.”

Whichever term we use, we’re measuring the body’s fundamental activity. Add speed into the equation and we can determine the body’s metabolic rate – the energy the body expends every minute to fuel its cells’ work.

It is all about counting atoms to track energy expenditure

How do you measure energy expenditure? In theory, it’s simple: you follow the CO2.

Whether it’s coal or carbohydrates, burning fuel creates a byproduct – carbon dioxide. When the body burns energy, it emits CO2. That’s largely what you’re exhaling when you breathe. Figure out how much CO2 the body produces, and you’ve got a precise measurement of how much energy it’s burning.

One way of tracking CO2 is to place a subject in a metabolic chamber – a sealed room with sensors that analyze oxygen and CO2 levels. This controlled environment yields accurate results, but what we really want to know is how much energy people expend in the real world.

In the 1950s, Nathan Lifson, a physiologist at the University of Minnesota, discovered an unobtrusive method of tracking CO2 production in people going about their normal day-to-day business.

Lifson’s breakthrough began with the observation that the human body, which is 65 percent water, is basically a large pool. There’s an inflow and an outflow. Hydrogen and oxygen atoms enter the body in food and drink, and they leave as urine, feces, sweat, and the vapor in our breath.

Hydrogen atoms always leave as water, but oxygen atoms have a second way of exiting the body. When carbon-based molecules are metabolized, CO2 is formed. The oxygen atom in this new CO2 molecule is taken from the body’s water. This atom is then ejected in the CO2 we exhale.

Lifson realized that tracking the rate of hydrogen and oxygen atoms leaving the body allowed him to calculate the rate of CO2 production, which in turn told him how much energy had been burned.

Tracing these atoms requires some complex chemistry, but the basic idea is to “label” them. To do this, you introduce hydrogen and oxygen isotopes, which are heavier forms of hydrogen and oxygen, into the body. Then, when the isotopes leave the body, you count them by analyzing urine samples.

If 10 percent of the hydrogen atoms in a subject’s body were deuterium – the hydrogen isotope – on Monday, but only 5 percent were deuterium on Wednesday, it’s clear that half of the body water has been expelled and replaced with regular H2O. It’s the same with oxygen-18, the oxygen isotope.

These measurements allow you to calculate the rate at which hydrogen and oxygen atoms were lost, which gives you the rate of CO2 production. That, in turn, is an index of how much energy – that is, how many calories – the body has burned.

Metabolically, we’re the same as our ancestors

Why are so many Westerners overweight? One common theory goes something like this.

The human body, including its metabolic system, evolved to cope with the environment in which the first Homo sapiens lived. Food was scarce, and these hunter-gatherers expended huge amounts of energy finding what little there was.

The theory contends that industrialization, which has given us cars, office jobs, and supermarkets, caused our modern weight problems. We’re not nearly as physically active as our ancestors, which means we’re failing to use our bodies as they were supposed to be used. No wonder we have metabolic issues!

It’s a neat theory, but new evidence suggests it’s wrong.

How can you prove or disprove the hypothesis that the West’s obesity pandemic comes down to the fact that we’re burning fewer calories per day than our prehistoric ancestors?

Finding out how much energy the average American or Italian expends every day is simple, but we can’t go back in time to study early humans’ metabolic systems. We can do the next best thing, though – we can examine the energy expenditure of modern people who live the same way.

Take the Hadza of northern Tanzania, one of the world’s few remaining populations of hunter-gatherers. Their life is physically demanding.

Hadza women spend most of the day digging tubers out of the stony soil and picking wild berries. Men, meanwhile, cover around twelve miles in the sun-scorched savanna hunting game and scaling 40-foot trees to harvest wild honey. In the evening, Hadza folk gather around campfires to share the fruits of their labor.

How much energy do they burn? According to the common theory, Hadza men and women should expend much more energy than their sedentary Western counterparts. But the results didn’t match that expectation.

On average, Hadza men eat and burn around 2,600 calories a day while women get through around 1,900 calories a day. That’s exactly the same amount as men and women burn on average in Europe and the United States. On the ground, the differences between a Hadza hunter-gatherer and someone driving to an office job in New York or Naples are stark. In terms of energy expenditure, though, they’re nonexistent.

The metabolism of humans is constrained or fixed

Are the Hadza results a weird anomaly?

Not really. Take a 2008 study by Amy Luke, a researcher at Loyola University Chicago. Luke used the Lifson method to compare the energy expenditure and physical activity of women living in rural Nigeria to African American women living in Chicago. Despite leading completely different lifestyles, it turned out that both groups expend the same amount of energy per day.

Then there’s Lara Dugas, another researcher at Loyola. She compared data from 98 studies from around the globe. Her conclusion? Sedentary populations in the developed world burn as much energy on average as people with much more physically demanding lives in the developing world.

In terms of energy use, it turns out, humans are pretty much the same wherever you look.

How is it that the Hadza spend the day outdoors foraging, hunting, and climbing trees without burning more calories than comparatively sedentary Western urbanites?

It’s likely that there are a couple of factors at play.

One part of the explanation is that highly active people like the Hadza subtly change their behavior to save energy. This might mean sitting rather than standing, or sleeping longer. The body also “budgets” its energy expenditure differently when we engage in lots of activity.

Usually, most of the calories we burn go toward fueling the work of cells and conducting cellular “housekeeping” – repairing wear and tear in the body. It seems that the body makes room in its limited energy budget for more activity by cutting down on these tasks. There’s evidence, for example, that exercise reduces the immune system’s inflammatory response as well as the production of hormones like estrogen.

We also know that energy expenditure plateaus at higher levels of activity. Researchers administered the Lifson test to 300 participants and monitored their activity using fitness trackers for seven days. The result? People with the most intensely active daily lives burned the same number of calories each day as those with moderately active lives.

All this evidence points toward a fascinating conclusion: our species has evolved strategies for keeping our daily energy expenditure constrained. That has big implications for public health. If daily energy expenditure hasn’t changed over the course of human history, obesity can’t be blamed on our sedentary lifestyles. Put differently, it’s not sloth that’s making us fat – it’s gluttony.

We are prone to obesity because of our evolutionary history

Charles Darwin observed that natural history is shaped by the struggle for resources. Because there’s never enough food to go around, species evolve under conditions of scarcity.

That’s why trade-offs are so important. Limited energy means you can’t have it all. Such limitations are clear to see in the case of evolutionary traits. For example, it could be that evolution provides a species with razor-sharp teeth – but also with tiny arms. That’s how you get the Tyrannosaurus rex. As Darwin put it in The Origin of Species, “to spend on one side, nature is forced to economize on the other side.”

There’s one species that flouts this principle, though – our own.

Humans are extravagant when it comes to energy. Consider the differences between us and our closest relatives, apes. Once you account for variables like body size and activity level, we consume around 400 more calories a day than chimpanzees and bonobos.

What do we do with these extra calories? Well, just keeping the body running is an expensive business. Take the brain. It’s so costly in terms of energy that every fourth breath we take goes toward feeding this three-pound organ. We also reproduce more often, have larger babies, live longer, and move more than apes. Are there trade-offs? Sure, our digestive tract is smaller and less costly than that of most apes, but that’s pretty much it.

At a cellular level, our bodies evolved to burn more energy. This was nothing less than a metabolic revolution, but it came with a downside. As our ancestors developed a faster metabolism, their risk of starvation increased. The more energy you need to function, after all, the worse it is when food runs out. The evolutionary solution to this problem haunts us to this day.

The simplest way of keeping an energy-guzzling machine like the human body fueled in an environment defined by scarcity is to store energy for later use. The body’s fuel-storage system is the fat cell. This also sets us apart from apes. Keep a chimpanzee in a zoo with lots of food and it’ll get bigger than its wild counterparts, but it’ll remain lean. Extra calories build bigger muscles and organs rather than paunches.

Under similar conditions, humans do get fat – and no wonder! We’ve evolved a response to food scarcity but we live in a world of caloric abundance. That’s the real mismatch between our bodies and our societies.

Sharing sparked the metabolic revolution

Apes and humans have a lot in common, including the fact that both are social animals. Of course, there are also lots of things that set us apart. Things like metabolism.

What caused this divergence? And why did our metabolic system outstrip that of apes? The short answer is that humans share food – and apes don’t.

The longer answer goes like this. Apes are capable of forming intricate and even lifelong social relationships, but they’re rugged individualists when it comes to food.

This shapes the way they approach the search for calories. Because their survival depends on it and no one else is going to help them, they go for the low-hanging fruit – literally and metaphorically. If you’re not going to share, why cooperate with others to hunt big game or gather enough fruit for a week?

That’s ultimately what held apes back.

Our ancestors were social foragers. Unlike apes, they didn’t abandon the hunt for calories once their stomachs were full – they also brought back food for others.

Sharing is a safety net. If someone is going to give you some of their food, it doesn’t matter if you return to your camp empty-handed – you’ll still survive. This safety net changes human behavior. It means you can take risks, like sending men out to hunt game knowing that they’ll fail nine times out of ten. That’s OK, though, because the women spent the day gathering tubers and berries, so there’s enough food for everyone anyway. And when the men do bring a wildebeest home, there’ll be a feast.

It’s likely that this social arrangement emerged among ape-brained hominins living in eastern Africa around two and a half million years ago. We don’t know a great deal about the origins of sharing, but there’s plenty of evidence of it from the more recent past. Zebra bones with cut marks are a great example. Bringing down a large, fast animal like a zebra requires teamwork, and teamwork only makes sense when everyone gets to share the spoils.

Social foraging changed humanity’s evolutionary path. Sharing meant there was more energy for life’s essential tasks. More people survived, more babies were born, and more time was spent experimenting with primitive tools. Hominins who shared outcompeted those who didn’t. Ultimately, the human body as we know it began to take shape. Metabolism sped up, creating the machinery that would come to support the energy-guzzling organ that defines us as a species – the brain.

Any food can help you lose weight as long as you’re burning more calories than you consume

Let’s recap. Metabolic research shows that modern urbanites with cars and comfy office chairs burn as many calories as hunter-gatherers. In other words, daily energy expenditure has likely remained unchanged since the Paleolithic era. We also know that daily energy expenditure is constrained, which means that increasing the amount we exercise has little effect on the number of calories we burn.

What should we make of these findings? Well, they suggest it’s time to rethink the way we go about tackling obesity. Simply put, exercise doesn’t do much to push the dial – but controlling our diets does.

Regular exercise has a ton of well-documented benefits, from heart health and stronger immune systems to improved brain function and healthier aging. It also helps suppress chronic inflammation, which has been linked to both cardiovascular disease and autoimmune disorders. That said, exercise isn’t an especially effective tool when it comes to weight management. As the old adage has it, you can’t outrun a bad diet.

Which brings us to dieting. There’s a lot of noise around this topic, so let’s cut to the chase: if you want to lose weight, you have to burn more calories than you consume. That’s just a basic law of physics.

The good news is that this means you’re free to pick the diet that works for you. Consider a 2005 study by Michael Dansinger, the current head of the Diabetes Reversal Program at Tufts Medical Center in Boston. His team randomly assigned 160 adults from Boston one of four popular diets for twelve months. These had different nutritional “philosophies.” Atkins, for example, is low carb, while Ornish is low fat. The other two diets – Weight Watchers and Zone – take a mix-and-match approach.

The result? Regardless of the diet, participants who stuck to it lost weight; those who didn’t failed to shed a pound.

The takeaway is that all diets work as long as you’re obeying that law of physics. Take it from Mark Haub, a professor of human nutrition at Kansas State University. Fed up with the pseudoscientific hype around so many diets, Haub designed his own diet, which consisted entirely of junk food. For ten weeks, he ate nothing but candy, cereals, chips, and cookies. Crucially, however, he never consumed more than 1,800 calories in a day. After two and a half months, he’d lost 27 pounds.

Now, no one, including Haub, is advocating this kind of diet – clearly, it’s a health disaster. But it’s worth pondering his point next time you come across someone advocating the latest wonder diet. At the end of the day, though, the principle remains the same – if you can burn the calories, you’ll burn the pounds, too.


Human life depends on the trillions of cells in our bodies. The work these cells do – producing everything from enzymes to neurotransmitters to DNA – requires energy. Calories provide that energy, and metabolism is the measure of how much energy we “burn.” 

Our metabolism has remained pretty much fixed since Paleolithic times. That’s why we all burn roughly the same number of calories, whether we’re sedentary urbanites or active hunter-gatherers. 

The conclusion? If exercise doesn’t make us burn more calories, obesity must be a product of gluttony rather than sloth.

Take a look at these popular supplement brands for full-body wellness and weight loss:

  • Resurge: According to the official website, Resurge’s formula is designed to help users recover from shallow sleep syndrome and improve the process of metabolic regeneration that occurs during sleep.
  • BioFit: This supplement contains probiotics selected for their ability to support digestion and bowel movement. 
  • Okinawa Flat Belly Tonic: This supplement supports a flat stomach and weight loss by optimizing metabolism and digestion.
  • Java Burn: A single-serve pack of Java Burn, according to its creator John Barban, can improve your energy levels and help you burn fat.

The loss of even 5 to 10 percent of your body weight can produce health benefits, including improvements in blood pressure, blood cholesterol, and blood sugar levels.

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