Why "Calories In, Calories Out" Doesn't Tell the Whole Story for Fat Loss

Eat less, move more. That's the general, cookie-cutter advice people get when they express a desire to lose body fat. As many of us understand it, your body composition depends on calories in and calories out: how many you consume compared to how many you burn. 

And at a very broad level, this will determine your body composition. If you consume more than you burn, you'll gain weight. If you consume less than you burn, you'll lose weight. And if the two numbers are roughly equal, your weight will hold steady.

Is it really that simple, though? 

table with breakfast foods

While, yes, you can manipulate your body weight and composition by manipulating your calories, there are a couple of other things we need to consider. Let's dive in. 

First of All, Not All Calories Are Created Equal

A calorie is a calorie is a calorie, right? 


Not all calories are the same. This is where macronutrients (also known as "macros") come into the conversation. 

Here's a very quick rundown.

There are three types of macros: (1) protein, (2) carbs, and (3) fat.

If "calories in, calories out" was all you needed to know about fat loss, then the assumption would be that 100 calories of protein are the same as 100 calories of carbs and 100 calories of fat. 

Except this isn't the case — not nearly. 

Your body responds differently to calories depending on what macro predominantly makes them up. For instance, your body processes chicken (mostly protein) differently from how it processes avocado (mostly fat with some carbs). 

slices of bread

This is why so many people have turned to counting their macros to change their body composition. By adjusting the number of grams of each macro that they consume in a given day, they're able to gain, lose, or maintain weight. 

And that brings us to our next point...

How Do You Adjust Your Macros to Change Your Weight?

To be very clear, your macro plan will need to be customized for you. What works for one person very well might not work for the next. (More on this in a minute.)

However, here are a few generally accepted beliefs. 

  • The more physically active you are, the more carbs you'll need. If you're mostly sedentary, you won't need very much.
  • Moderately active people should aim for roughly one gram of protein per pound of body weight. 
  • Fats typically make up the smallest macro group, but mainly because they're more calorie-dense than carbs and protein. Carbs and protein have four calories per gram, while fat has nine calories per gram.
  • Try to break up your daily protein and include some in every meal and snack. This helps keep you satiated and energized.
  • Quick carbs are best consumed immediately before, during, or after training. 
  • Fat slows down digestion. Stick to protein and carbs post-training, since that's what your body immediately needs to start recovering.

We want to reiterate that your macros/calories depend on a number of factors, and there's no one-size-fits-all approach. Let's get into that a little bit more now.

Many Other Factors Outside of Calories Play a Role in Your Body Weight

If weight manipulation was as straightforward as calories in, calories out, losing weight wouldn't be the mystery that it is for so many of us. While it's absolutely important, you have to know that there are other variables playing a part in the number you see on the scale. 

Here are just a few examples.

Any Medications That You Take

Are you taking medication for diabetes? How about steroids like prednisone or something like birth control pills? What about antidepressants? 

We bring this up because certain medications can cause weight gain.

pills in a pill box

This doesn't mean that it's going to be impossible to lose weight. But it's still something you'll need to consider when coming up with the appropriate training plan and nutrition programming for you and your goals.

Your Age

"When I was younger, I was a twig!" We've all heard our parents or grandparents say that at least once in our lives. And it's because the older you get, the more challenging it becomes to shed body fat.

It could be that your lifestyle changes — such as getting less physical activity. But also, for many of us, our metabolisms simply slow down. Also, we lose muscle mass as we age, which means that our resting metabolic rate slows down.

In other words, our bodies burn fewer calories at rest.

There's a reason why when you were a kid, you could eat get away with eating anything, but as an adult, you gain weight looking at pizza.

pizza and pop

Certain Medical Conditions

Cushing's syndrome can lead to weight gain, and so can hypothyroidism (an underactive thyroid). Hyperthyroidism, on the other hand, can make the weight fall off.

Again, because multiple variables determine your body weight and composition, you won't lose complete control if a medical condition is making you gain or lose pounds. However, as we've already said, you'll want to take any illnesses into consideration when figuring out a lifestyle that's most effective for you.

How Active You Are (and What You Do)

This one is likely a given, but it's worth talking about anyway.

Many say fitness is king and nutrition is queen. And that's because having a solid plan for one is good and all, but when you knock both out of the park, the results are undeniable.

You can achieve a lot with a diet that's on-point, but if you're mostly sedentary, you're going to hit a plateau, and probably sooner rather than later.

Low-intensity activities like basic yoga and walking are great for moving your body. Higher-intensity movements like weightlifting and functional fitness will move the needle even more. 

woman doing yoga

So, once again, calories in, calories out matters. But you can have two identical people consuming the same calories with the same macro breakdown. If one is physically active and the other isn't, who do you think is going to have more control over their body composition?

The Takeaway

Do you need to be a nutrition and fitness expert to ignite a change in your body? Not at all. And the truth is that if you're living a pretty unhealthy lifestyle right now, even modest changes can have a big impact. 

But as you get more healthy and fit, you're going to need to pull the reigns in and really tighten up your nutrition and training. That's when you'll need to really look beyond total calorie consumption and expenditure and get into the nitty-gritty more — especially if you're going to attempt to train in a calorie deficit.

And of course, having a reliable way to track your fitness and your progress along the journey is always helpful. That's where Atlas Wearables comes in.