The Misconceptions of Calories in vs Calories out

Updated: Nov 26, 2020

The concept of calories in vs calories out for weight loss is one of the hot topics that is constantly being debated. Some argue it is the be-all and end-all of weight loss. Others say it’s flawed and oversimplified.

In theory, the calories in vs calories out makes sense. Here is the basic equation:

Change in weight = calories in – calories out.

This is about as close to scientific fact as we can get, however it is 100% irrelevant to human health. Why? Because as humans, we are much more complicated than a simple math equation.

The idea that simply counting calories and following the ‘calories in, calories out’ philosophy is the answer to health and weight is highly misunderstood. It is true that calories have the same amount of energy, regardless of the source, but in order to truly lose weight for the long-term, it is important to understand why this philosophy and calorie restriction does not work.

Let me begin with this scenario, I am sure we’ve all done this before.

You want to lose some weight, so you input your personal details into an online calculator which then gives you the number of calories you should eat per day. You then use an app on your phone to track everything you eat and make sure you stay under that number. It works, for a little while, you lose some weight, you feel good, but then the weight loss stops. You get upset so you treat yourself to the food you have been restricting. You start losing your will power, and slowly you end up back right where you started.

Sounds about right? I have been there and done that.

Calories vs Nutrients

Essentially, a calorie is a unit of energy and the number of calories contained in a food tell us how much energy that particular food provides.

However, not all calories are created equally.

While a sweet potato and a chocolate bar may both contain 200 calories, and 100 calories from carrots is the same as 100 calories from crisps, but the nutrients that those calories come with is the biggest reason why the nutritional benefit from each calorie is different, it’s never the same.

Our bodies are not math equations, we are complex systems with thousands of chemical reactions occurring at one time.

Calories are used for cellular function, brain function, body temperature, immune system, for our hair and nails to grow, to manage our hormones and so much more! So every time that you put food in your mouth you are setting off a complex chain of reactions across all of your bodily systems, and it is the nutrients present in the food that we eat that are responsible for these reactions.

A calorie is simply not a calorie. Food quality matters more than calories.

Balance of Macronutrients

Macronutrients are carbohydrates, proteins, and fats which all have important roles in our body. Therefore, it is vital to our health to consume an appropriate balance of these three macronutrients.

Consuming 2,000 calories per day of solely carbohydrates does not provide the same health benefits as consuming 2,000 calories per day from a balance of carbohydrates, proteins, and fats. A daily intake of 2,000 calories from sandwiches, pasta, cookies, and pastries (carbs, carbs, carbs, carbs) will have a very different impact on the body than a well-balanced day of porridge, chicken, and avocado (carbs, proteins, and fats).

WHERE your calories come from is far more important than how MUCH you are consuming.

Satiety Levels

Different foods impact different systems in the body and have different effects on our satiety.

Consuming 230 calories from Reese’s Peanut Butter cups compared to 230 calories from 3 eggs is less filling and much less satiating to our bodies.

Processed foods are hyper-palatable making them very easy to over-consume. Whereas, whole foods, especially whole food sources of protein and fat, are incredibly filling and satiating to us.

Eating 230 calories of eggs will not only provide high-quality nutrients but will keep us fuelled for hours, where the same amount of calories of Reese’s Peanut Butter cups is more likely to create unbalanced blood sugar levels and trigger more sugar cravings within hours or even minutes of eating.

Calories from real whole food are high on the satiety index – which means, you need less to stay full. While processed foods are low on the satiety index, as they end up leaving you even hungrier than before.

Calorie Restriction is Not For Long-Term

In the beginning, cutting back on calories can be easy, which allows you to lose some weight, which then gives you the illusion that you can continue this long-term.

However, our bodies are smart, and their job is to protect us. The more you cut calories out of your day, the more your body will adapt and fight against it. Your body will switch to survival mode slowing down the metabolic rate, in order for your body to burn fewer calories.

As you continue to restrict calories, your body will adapt to the amount of calories you’ve given it which then burns fewer calories in order to balance out the calories you’re consuming. In the long-term, your body will burn fewer calories, forcing you to eat fewer calories in order to lose the weight, eventually, this will lead you to just run out of calories to restrict.

Hormones vs Calories

Hormones such as insulin and glucagon play a vital role in blood sugar regulation, and in turn fat storage. In addition, other hormones such as leptin and ghrelin play a vital role in hunger, cravings, and satiety.

There are many factors that can affect these hormones, not just calories, including lifestyle factors such as sleep and stress, which can affect additional hormones such as cortisol and thyroid hormones.

A shift in one hormone will cause a shift in another and another, and they will all have an impact on calories and therefore on your weight loss or weight gain. You can count your calories for as long as you want, but if you are not paying attention to food quality, sleep, stress and other lifestyle factors it will be very difficult for you to lose weight and more importantly, keeping that weight off in the long term.

So instead of using your calorie calculator, here are 5 practical tips to consider when it comes to eating well.

1. Address Food Quality

Honestly, the single most important factor to long-term sustainable weight loss is food quality.

It doesn’t matter if you are eating the perfect amount of food, at the perfect time, if you are doing it with processed and refined food, it is going to make weight loss a difficult.

It is important to understand that a calorie is not a calorie and that everything we put in our mouth affects every system of our body. The carbohydrates, proteins, fats, vitamins, and minerals present in the food that you eat all determine whether or not your body can and will lose weight. If you are eating processed food with refined carbohydrates and refined sugar, vegetable oils, additives, and preservatives it is going to make weight loss more difficult and less sustainable.

2. Don’t Restrict Calories

Although calorie restriction may work in the short-term, in the long-term it is a faulty plan. Like I mentioned earlier, our body’s job is to protect us and the more you cut calories out of your day, the more your body will adapt and fight against it. Which in turn will slow down the metabolic rate, in order for your body to burn fewer calories.

3. Consume Well-Balanced Meals

Ensuring that you are consuming well-balanced meals throughout the day with complex carbohydrates, proteins and healthy fats are essential to helping you reach and maintain your weight loss goals, without the need to count calories. Eating an adequate amount of protein and healthy fat in your meals can help to balance your blood sugar and reduce your hunger and cravings.

4. Get Good Quality Sleep

Sleep is vital for weight loss because the amount of sleep you get directly affects how much food you consume. Studies show that sleep-deprived individuals have a bigger appetite and tend to consume more. Sleep deprivation disrupts the daily fluctuations in appetite hormones and is believed to cause poor appetite regulation (1,2).

5. Manage Stress

Stress plays a huge role in managing weight as stress has a large impact on hormones. In the short-term stress can be beneficial as it helps you get through important life events, but long-term chronic stress can be detrimental to your weight, due to it affecting your cortisol levels.

Cortisol is the body’s main stress hormone. It manages the body’s use of carbohydrates, fats, and proteins, reduces inflammation, manages blood sugar, regulates blood pressure, controls our sleep-wake cycle, and boosts energy so you can handle stress and restores balance after stressful periods (7).

However, studies show that chronic long-term stress can increase cortisol levels, and disrupt the natural cortisol rhythm, and this becomes problematic for weight (3,4). Not only can high cortisol levels cause you to crave more sweets, sugar and junk food (5,6), but our body will store energy as a protective mechanism, particularly in stressful situations, in the form of visceral fat on and around the belly (3,4). Whether the stressors are perceived, or lifestyle-based, the stress response makes it more difficult to lose weight as the body is actually working to protect us against this chronic stress.

Bottom Line

Calories in vs calories out is a flawed philosophy for long term weight loss. The human body is way more complicated than a simple math equation. It is about focusing on food quality over food quantity to support bodily functions and systems. It is about regulating hormones by balancing insulin levels and managing blood sugar. It is about focusing on healthy lifestyle factors, managing stress and getting good-quality sleep.

You don’t need to restrict calories, you need to slow down and focus on the bigger picture. Finally, a gentle reminder that this will not happen overnight, but if you make the right changes in the right way it will last a lifetime.



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2) Markwald, R. R., Melanson, E. L., Smith, M. R., Higgins, J., Perreault, L., Eckel, R. H., & Wright, K. P., Jr (2013). Impact of insufficient sleep on total daily energy expenditure, food intake, and weight gain. Proceedings of the National Academy of Sciences of the United States of America, 110(14), 5695–5700.

3) van der Valk, E. S., Savas, M., & van Rossum, E. (2018). Stress and Obesity: Are There More Susceptible Individuals? Current obesity reports, 7(2), 193–203.

4) Chao, A. M., Jastreboff, A. M., White, M. A., Grilo, C. M., & Sinha, R. (2017). Stress, cortisol, and other appetite-related hormones: Prospective prediction of 6-month changes in food cravings and weight. Obesity (Silver Spring, Md.), 25(4), 713–720.

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7) Thau L, Sharma S. Physiology, Cortisol. [Updated 2019 Feb 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019.