Calories In Calories Out: The Complex Path to Weight Loss

You've heard the saying "calories in calories out," but it's often easier said than done. Maybe you diligently track your calorie intake, religiously hit the gym, and yet see the scale barely budge.

It can feel like you're stuck on a frustrating merry-go-round, with confusing and conflicting advice coming at you from every direction.

You're not alone. The relationship between what we eat, how our bodies move, and how they respond is far more intricate than simply adding and subtracting calories. Many factors can influence your weight loss journey—and some are sneakier than others.

This article explores the complexities behind "calories in calories out," examining those hidden players and offering realistic tips to take control of your well-being.

Beyond a Simple Equation

At its core, successful weight loss management involves the balance of energy: consuming fewer calories than your body uses.

This principle, often shortened to "calories in, calories out" (CICO), has been proven repeatedly. This means you'll probably need to count, or at least consider, calories to gain weight, maintain it, or lose weight.

Several randomized controlled trials considered the gold standard in research, consistently show that both low-fat and low-carb diets are equally effective so long as a calorie deficit exists. These studies emphasize that calorie balance plays a significant role in weight loss.

The Big Problem... Our Bodies Aren't Calorie Calculators

Here's where the plot thickens... while the core principle of CICO holds true, thinking of our bodies like calculators doing simple arithmetic just doesn't work.

Several surprising factors impact both sides of the equation, often without us even realizing it. Let's uncover some of those hidden culprits.

Your Body's Control Center: The Mighty Hypothalamus 

Imagine a tiny control room nestled deep within your brain—that's your hypothalamus. This tiny powerhouse doesn't get enough credit for the intricate role it plays in weight management. Your food intake relies on your hypothalamus to function.

Your hypothalamus orchestrates a complex symphony of hormones influencing everything from hunger signals and calorie burn rate to energy expenditure and even where your body stores fat.

It's on constant alert, monitoring your energy levels and adjusting based on various factors, such as your basal metabolic rate (BMR).

Hormonal Harmony (Or Disharmony) Matters 

Hormones are chemical messengers sending instructions throughout your body—think of them as your internal communication system. However, when it comes to body weight, they're not always singing in perfect harmony.

Factors like stress, lack of sleep, certain medications, and even the foods you eat can cause these hormones to act a bit wonky, sometimes wreaking havoc on your caloric burn rate and, yes, impacting your "calories in calories out" balance.

Factors like these are why some claim "CICO doesn't work," when in reality, there's more to it than a simple statement. Ever noticed how a stressful day can leave you craving sugary treats or three glasses of wine?

That's the stress hormone, cortisol, hijacking your cravings. Cortisol's primary function is to keep your body fueled and ready for action in times of stress. More on that later.

"Set Point Weight" - Your Body's Comfort Zone

Did you know your body might have a preferred weight range it likes to stick to? It's called your "set point weight." Our bodies are amazing at self-preservation.

If you significantly reduce your caloric intake for a long time (hello, restrictive dieting), your metabolism might slow down to conserve energy. It's an internal survival technique. This is why people hit "plateaus."

This mechanism, in part, is why losing weight is more complex than just "calories in calories out." Many other factors influence your weight.

One surprising study tracked contestants from the show "The Biggest Loser." Even after significant weight loss through intense diet and exercise, their bodies fought back.

Despite their new weight, their bodies clung to a previous "comfort zone," illustrating that sustained lifestyle changes often matter more than drastic short-term efforts.

"Calories In": Not as Straightforward as It Seems

Tracking calorie intake feels clear-cut, but is it really? While diligently noting those numbers in a food diary gives you valuable awareness, let's face it, calorie counting is an imperfect system.

However, it's still important when trying to understand the "calories in calories out" principle to lose weight.

Labeling Discrepancies

Did you ever consider that those calorie counts on food packages are actually estimates, with a surprisingly wide margin of error allowed? 

A broadly accepted discrepancy of up to 20% is permitted by the FDA. This means your total calorie intake may be up to 20% more than you realize. Because think about it... the food companies aren't going to over-estimate how many calories are in those junk foods they promote!

This study from Australia sheds light on how much this variation impacts things; food items contained anywhere between 13 percent less and 61 percent more calories than what the label claimed.

Think about it—that seemingly innocent 200-calorie snack pack could clock in at nearly 320 calories. 

Now multiply that by several snacks a week or inaccurate meals each day, and suddenly your perceived "calories in" could be vastly different from what you’re actually consuming. 

This isn’t about demonizing specific foods, but rather highlighting that accurately tracking what we put into our bodies is much more complex than reading a label. 

Even more "fascinating" is that even when nutritionists log their own food, they tend to underestimate their "calories in" by 30 to 40% and their "calories out" by up to 50%. Not good for the energy balance, right? If nutritionists do this, it's highly likely you do too!

It's About "What" You Eat!

A 2019 study found that what you eat matters more than you realize -- even if caloric intake is equal.

People eating ultra-processed foods and fast foods eat more calories and gain more weight than those who ate a minimally processed diet.

This occurred even though the meals provided to each group in the study (processed food vs. real foods) contained the same number of calories.

This tightly controlled study showed a clear difference between those eating processed foods vs. non-processed foods.

Are Artificial Sweeteners a Help or a Hindrance

Artificial sweeteners have become the go-to for those who want a sweet taste without the calories. Although it seems like artificial sweeteners should affect your CICO energy balance positively, is it working out in real time? 

Many national authorities recognize artificial sweeteners as safe and well-tolerated. But a ton of controversy remains.

Some studies show a link between artificial sweetener consumption and reduced risk of weight gain and diabetes... whereas other studies show a positive correlation between artificial sweeteners and obesity, diabetes, heart conditions, and stroke.

For example, this human study showed that the use of artificial sweeteners increased the risk of insulin resistance.

It has been shown that the brain can sense calorie differences in foods with different sweeteners but with equal sweetness. However, to our knowledge, there's been no systematic review of differences in brain processing for artificial sweeteners vs. sugar.

It's also hard to evaluate artificial sweeteners because each one metabolizes in your body differently from the others. So, you can't extrapolate the results for one sweetener to a different sweetener. 

Also, most studies have looked at short-term results, not long-term effects. Given the little we do know about potentially increasing insulin resistance and possibly diabetes, you might try weaning yourself off both sugary drinks and artificially sweetened drinks.

Both have the potential to cause harm and neither provides any essential nutrients for sustaining life. 

"Calories Out": It's Not Just About Gym Time - Exercise Active Thermogenesis (EAT)

Many people focus on those heart-pumping gym sessions when they think "calories out." It's true that exercise is important and can affect our "calories out." But not every type of exercise creates an equal impact on "calories out" either.

Strength training (i.e., resistance training) and HIIT (high-intensity interval training) are best in terms of increased calorie burn, as they keep on burning calories for hours after you stop exercising.

So be sure to incorporate them into your exercise regimen, especially if you're trying to shed some pounds.

But focusing only on hour-long workouts overlooks the multitude of ways we burn calories throughout the day, like with non-exercise activity thermogenesis (NEAT).

The Power of NEAT

Enter NEAT: Non-Exercise Activity Thermogenesis—in simple terms, the energy you use doing everyday things besides your workout routine.

We're talking fidgeting, walking to the mailbox, doing chores around the house, and even just standing instead of sitting.

It may seem insignificant, but those seemingly small activities do add up. Your total calories burned each day take NEAT into account, so it's important to get up and move as often as you can.

You can even set your computer or smartwatch to remind you to move. Increased movement throughout your day can dramatically impact your “calories out,” tipping the scales in your favor, without needing more time at the gym.

Your Basal Metabolic Rate (BMR)

Your BMR is personal to you. BMR is defined as the calories burned at rest if you're lying in bed for 24 hours. It covers the very basic functions to keep you alive, including breathing, circulation, and oxygen and nutrient delivery. 

Some people have a faster-burning BMR than others. Count your blessings if you're one of them.

TEF: The Calories Burned by Simply Eating

Yes, you read that right—even digestion requires energy. This fascinating process is known as the Thermic Effect of Food (TEF) and can account for about 10% of your daily calorie burn.

Various foods burn different amounts of calories just through the digestive process. Want to eat the foods that burn the most calories as TEF? Eat more protein. Protein burns 20 to 35% of its calories as TEF.

A bonus for eating more protein? It promotes satiety so it'll keep you satisfied and not reaching for starchy snacks all day long. In fact, protein was the best macro-nutrient for satiety across 50 studies.

This means choosing more lean protein sources when possible. By contrast, carbs burn 5 to 10% of their calories as TEF and fat burns 0 to 5%.

Stress and Sleep

Ongoing stress releases the stress hormone, cortisol, which is your weight loss enemy. Constantly elevated cortisol levels due to chronic stress can contribute to stubborn pounds hanging around. And everyone's levels of cortisol vary.

For some, constant stress leads to weight loss. Others hit the pantry and gain weight. The main takeaway is that stress wreaks havoc on our bodies. 

Learning to manage your stress with yoga, meditation, or breathing techniques can be helpful. Managing stress can also improve your sleep, which is another underrated aspect of weight loss.

Sleep affects your appetite in ways you never even thought possible, namely by hormones. For example, sleep deprivation can make junk food more appealing, and staying up late at night can increase the desire for fatty and high-calorie foods.

On the flip side, adequate restful sleep has a strong influence on long-term weight control. To reap the health benefits of sleep, aim for 7 to 9 hours of rest per night.

Establish a consistent sleep schedule. Go to bed and wake up at the same time every day – even on weekends. This helps regulate your body’s internal clock and can make it easier to fall asleep and wake up naturally.

Conclusion

While "calories in calories out" remains a useful concept, our bodies are anything but simple equations and we shouldn't expect it to function in such an oversimplified way.

Weight loss is a multifaceted journey, and "calories in calories out" is just one component of it.

Hormones like cortisol, the elusive "set point" theory, food label discrepancies, and those often-overlooked calorie-burning activities like NEAT demonstrate why a one-size-fits-all approach rarely leads to lasting success.

Still, trying to eat less and move more -- while reducing stress and improving sleep -- can add fuel to your weight loss journey and help you tip the scales in your favor without feeling deprived. 

Frequently Asked Questions

Should you stop counting calories?

Even though calorie counting is an imperfect system, it's still important when trying to understand the "calories in calories out" principle. Studies emphasize that calorie balance plays a significant role in weight loss.

Is the CICO diet, "calories in calories out", best for weight loss?

The "calories in, calories out" (CICO) approach is a foundational principle for weight loss, as it focuses on creating a calorie deficit.

However, factors like the quality of calories, hormonal responses, and macronutrient balance also play crucial roles in losing weight.

For long-term success, it's important to consider both the quantity and quality of food, along with adopting healthy, sustainable habits rather than just focusing on calorie counting. And consuming whole foods is far better than processed foods, because it brings control of ingredients and calories back to you!

What are the best types of exercises to increase calorie burn?

Strength training (resistance training) and high-intensity interval training (HIIT) are particularly effective for boosting calorie burn, as they continue to burn calories for hours after your workout ends.

To maximize weight loss, be sure to include both in your exercise routine.

What are the best foods to increase calorie burn?

The best foods for burning calories are those high in protein, as protein burns 20 to 35% of its calories through digestion due to the Thermic Effect of Food (TEF).

Protein also promotes satiety, helping you feel more full for longer and reducing the urge to snack. By comparison, carbohydrates burn 5 to 10% of their calories through TEF, while fat burns only 0 to 5%.