It comes in various shapes and sizes: “do more cardio to lose weight,” “eat 500 fewer calories each day to lose 1 pound of fat per week,” and other derivatives like “drink water so you feel more full” and “fill up on low-calorie foods like salads and veggies.”

It’s now so commonplace that it has become ingrained as truth: if you want to lose fat, just eat less and exercise more. It’s so simple!

But if it was really that simple, why is such a large portion of the population overweight or obese? Why do people struggle, often for their whole lives, to lose fat or stay skinny? It’s definitely not for lack of trying.

Maybe this ingrained truth isn’t so truthful after all. Maybe it has set the entire health and fitness industry back for a century, if not more. More importantly, maybe it has set the health of the entire population back for generations.

The idea of eating less and exercising more for fat loss more is founded on the concept of caloric balance, or the balance between calories-in (from the food we eat) and calories-out (from exercise and well, everything else the body does).

Calories are simply a measure of energy. So from this view, excess body fat, a storage form of energy, is a result of excess energy, or too many calories in and not enough calories out. It’s a simple problem with a simple solution: eat fewer calories and expend more calories, or eat less and exercise more!

And where has this left us? Constantly restricting ourselves, constantly forcing ourselves to exercise, and constantly not getting the results that we put so much effort towards. And worse, often we’re left with cravings, fatigue, and deteriorating health.

It’s a simple, logical equation: if you have fewer calories in than calories out, you lose fat. So where did we go wrong?

This equation ignores everything that separates us from calorie-calculating machines. We don’t exist in a vacuum. We exist in diverse, ever-changing environments. And what separates us and all other organisms from calorie-calculating machines is the ability to adapt to these environments.

If the human body senses that its environment is too hot, it increases its sweat rate and blood profusion to the skin to keep itself cool. If it senses it’s getting burned, it reflexively takes its hand off the stove. And what happens if the body senses that it doesn’t have enough energy, the force that powers every single cell? It tries to conserve as much energy as possible.

How does this relate to eating less and exercising more?

Eating less results in fewer nutrients (including calories) from which the body can create energy. Exercising more increases the energy the body expends. In other words, eating less and exercising more results in a decreased energy supply and an increased energy demand.

In order to adapt to this energy imbalance, the body first tries to conserve as much energy as possible by reducing its energy usage and decreasing its energy production (1, 2, 3, 4, 5, 6, 7). At the same time, this energy imbalance causes us to feel hungry and tired, encouraging us to eat and rest to restore the balance between energy supply and demand. Think of it as “low-battery mode” for your body.

If we continue to eat less and exercise more, this causes stress (8). Not psychological stress, like the feeling of an impending deadline, a fight with a significant other, or hosting your family for the holidays (although these can all contribute to this kind of stress). This is physiological stress.

When physiological stress occurs, our bodies begin using their emergency energy stores (fat, muscles, and other tissues) and further decrease their metabolism, or energy production. If this continues chronically, we may lose fat (along with muscle and other tissue) as our bodies use it as an emergency energy source. But, this fat loss comes at a high cost.

 

The Cost of Energy Imbalance

Chronic energy imbalance, or “low-battery mode,” results in a constantly lowered metabolism and reduced energy usage to decrease the energy demand and store as much energy as possible (1, 2, 3, 4, 5, 6, 7, 9).

This combination leaves less energy available for our bodies to use. Without enough energy, the body, starting at each individual cell, can’t function properly. Our brains can’t think clearly and quickly, our skin and hair can’t stay strong and healthy, and our immune systems can’t function properly. This energy imbalance essentially leads to deterioration of the entire bodily system and can lead to many of the chronic health conditions that plague our population today.

It also results in an increased likelihood to gain fat. Fat serves as our emergency energy supply, so instead of using food to produce energy, energy imbalance encourages our bodies to try to store more food as fat in case of future stress (10, 11). In other words, if we ever give in to the hunger or cancel our gym membership, we’re more likely to gain fat!

So, can you lose fat by eating less and exercising more? Yeah, definitely.

But the real question is, can you lose fat without feeling constant hunger and fatigue, slaving away at the gym every day, and compromising your health?

And the short answer is yes!

Let’s put it this way. If eating fewer calories and exercising more leads to an energy imbalance, which opposes fat loss and health, then eating more calories and exercising less should lead to an energy balance, which should encourage fat loss. And it does!

But of course, it’s not quite that simple. Other factors can affect our energy supply and demand, like which foods we eat, psychological stress, sleep, and many other aspects of our environment. And, as long as it isn’t done in excess, physical activity can have many benefits, including improving energy production.

One component of our diets that affects energy supply and demand is the amount of carbohydrates, fat, and protein we eat. In the next part of this fat loss series, I’ll explain why the notions that “eating carbohydrates causes fat gain” and that you should “be a fat-burner to lose fat” are just as misguided as the concept of eating less and exercising more for fat loss and health.

 

References