In the world of nutrition, the concept of “calories in, calories out” (CICO) has long been touted as the fundamental principle of weight management. The idea is simple: if you consume more calories than you burn, you gain weight; if you burn more calories than you consume, you lose weight. Read this article for free: Already have an account? To continue reading, please subscribe: * In the world of nutrition, the concept of “calories in, calories out” (CICO) has long been touted as the fundamental principle of weight management.
The idea is simple: if you consume more calories than you burn, you gain weight; if you burn more calories than you consume, you lose weight. Read unlimited articles for free today: Already have an account? In the world of nutrition, the concept of “calories in, calories out” (CICO) has long been touted as the fundamental principle of weight management. The idea is simple: if you consume more calories than you burn, you gain weight; if you burn more calories than you consume, you lose weight.
All diets work by abiding by this rule, despite claims made by charlatans promoting other schemes not relevant to the context of this column. Despite being a big believer in controlling calories for weight loss — I have roughly 1,600 client case studies to lean on to this point — the concept is an oversimplification. Pickled Stardust / Unsplash Consume more calories than you burn, and you’ll gain weight.
The truth is, the human body is complex, and many factors influence how we gain or lose weight. At its core, CICO is based on the first law of thermodynamics, which states that energy cannot be created or destroyed, only transferred. When applied to the human body, this means the energy (calories) you consume must be used, stored or expelled.
This is the basic premise behind most weight-loss advice: eat less, move more. And for many, this approach works — to a point. But it’s not the whole story.
In the early 2000s, I was stuck in a frustrating cycle. I was eating what I thought was a “clean” diet, exercising regularly, and yet, the scale refused to budge. Despite my best efforts, the extra 60 pounds I was carrying around weren’t going anywhere, beyond gaining a little momentum only to lose it.
I felt like I was doing everything right, but something just wasn’t clicking. It wasn’t until I hired a coach that things started to change. My coach insisted I start tracking my calories, something I hadn’t done before.
At first, I was skeptical — how could something as simple as counting calories make a difference when I was already eating healthy? I had more than enough chicken and sweet potato, so why count it. But as I began logging every bite, I quickly realized how the little things were causing big problems. A handful of nuts here, an extra spoonful of peanut butter there and even the healthy smoothies I was drinking, all those “small” indulgences were easily pushing me into a calorie surplus more days than I realized.
My coach helped me see that, while I was eating clean, I was still consuming more calories than I thought. This was the turning point. By becoming mindful of my calorie intake and making slight adjustments, I finally began to lose the weight that had been holding me back for so long.
This experience taught me a valuable lesson: it’s not just about what you eat, but how much. Even healthy foods can hinder progress if you’re not mindful of portion sizes and overall intake. Understanding this balance was key to my transformation, and it’s something I emphasize with my clients today.
I got lucky. I was in my 20s without a whole lot of stress and wear-and-tear. The human body is not necessarily a simple machine that strictly adheres to the laws of physics at all stages.
We aren’t AI robots (yet). Various factors can influence how calories are processed and how energy is used, so if you’re stuck “doing everything right,” read the rest of this column for the reasons why that might be. : When you reduce your calorie intake, your body doesn’t just burn the same number of calories it always has.
Instead, it adapts by lowering your metabolic rate. This is an evolutionary response designed to prevent starvation. The longer and more drastically you cut calories, the more your metabolism adjusts.
It’s largely driven by the fact you’re a lighter body than when you started, so you require fewer calories to sustain your new weight. This is why some people hit weight-loss plateaus — they’re eating less, but their bodies have adapted to burn fewer calories. : Hormones play a significant role in weight management.
For example, insulin is a hormone that regulates blood sugar and fat storage. High insulin levels can promote fat storage and make it harder to lose weight. Ghrelin and leptin are hormones that regulate hunger and satiety.
An imbalance in these hormones can lead to overeating, even if you’re consuming the same number of calories as someone else who doesn’t have the same hormonal issues. This is the basic premise of the new class of GLP-1 drugs, such as Ozempic, which help regulate hunger. These drugs mimic the action of a hormone called glucagon-like peptide 1 so you feel full for much longer than you would without.
These drugs also slow the movement of food from the stomach into the small intestine. As a result, you eat less. There’s no free lunch here and side effects vary person to person, but there’s no disputing the fact they suppress the heightened hunger associated with calorie restriction (which varies from individual to individual).
: The trillions of bacteria in your gut can also influence how your body processes calories. Some studies have shown even the composition of gut microbiota can affect the number of calories your body extracts from food and how those calories are stored or used. Individuals with a higher ratio of Firmicutes to Bacteroidetes bacteria, for example, may extract more calories from the same amount of food compared to someone with a different gut-bacteria composition.
A lot of this is still inconclusive, but one of the most relevant points of discussion we do have good intel on is the difference between whole and processed foods, as well as the role of protein and the thermic effect of food (TEF). Whole foods, such as fruits, vegetables, whole grains and lean proteins, require more energy to digest and metabolize compared to processed foods. This is because whole foods are generally more complex in structure, containing fibre, water and other nutrients that take longer for the body to break down.
This higher energy expenditure during digestion is part of what’s known as the thermic effect of food (TEF), which refers to the increase in metabolic rate after eating. Processed foods, on the other hand, are often stripped of fibre and are lower in protein and nutrients, making them easier for the body to digest and absorb quickly. This means you likely absorb more calories per-gram from processed foods than from whole foods, even if the calorie content appears similar on a nutrition label.
For example, a 100-calorie portion of a processed snack might be absorbed almost entirely by your body, whereas a 100-calorie portion of vegetables and lean proteins results in fewer net calories being absorbed due to the higher TEF and the body’s effort to digest the fibre and complex carbohydrates. : Stress, sleep and mental health can all influence your eating habits and metabolism. Chronic stress can lead to elevated cortisol levels, which can increase appetite and promote fat storage, particularly in the abdominal area.
Lack of sleep can disrupt hunger hormones and lead to increased calorie intake. It’s more the impact it has on your behaviours than anything, but it’s an impact all the same. Despite these complexities, the basic principle of CICO still holds.
If you consistently consume more calories than your body uses, you’ll gain weight. This has been proven in numerous studies, including tightly controlled metabolic ward studies where participants’ calorie intake and expenditure were meticulously monitored. If you’re not paying attention to how much you’re eating, it’s very easy to overeat without realizing, even if you’re exercising regularly.
Even in research where activity levels were elevated to over an hour per day, some participants maintained or even gained weight despite increasing their exercise. The researchers explained the lack of weight loss in these individuals was due to an increase in caloric intake and hunger, heightened cravings for sweets and compensatory health beliefs (such as, “I exercised, so I deserve to eat more.”) Some experienced energy compensation — they saw a bigger drop in their non-exercise activity thermogenesis (all the movement not deemed deliberate exercise over the other hours of the day).
The point still remains that understanding the nuances of how your body processes calories can help you make more informed choices. Someone who is struggling to lose weight despite eating what they believe is a calorie deficit might benefit from looking at factors like hormonal balance, sleep quality, stress levels and the composition of their diet beyond just calories. Given the complexities of how the body processes calories, here are some practical tips for managing your calorie intake and expenditure, if your goal is weight loss: : Whole, unprocessed foods tend to be more filling and nutrient-dense, which can help you feel satisfied on fewer calories.
They also tend to be lower in added sugars and unhealthy fats, which can contribute to weight gain. And, as discussed, they take more “effort” for your body to break down, burning more calories. : Along those same lines, protein also has a higher thermic effect, meaning your body burns more calories digesting protein than it does digesting carbs or fats.
Protein has a particularly high TEF, with about 20-30 per cent of the calories from protein being used up (technically, they don’t count) just to digest and metabolize it. This is significantly higher than the TEF for carbohydrates (five to 10 per cent) and fats (zero to three per cent). This means if you consume 100 calories from protein, your body might only net about 70-80 of those calories after accounting for the energy used in digestion.
This higher energy expenditure is one reason why diets higher in protein can be more effective for weight management. It also plays a role in preserving muscle mass, which becomes particularly important when striving to lose fat, not just weight overall. : Calories such as those from sugary drinks or alcohol can add up quickly without making you feel as full as whole foods.
Cutting back on these can be an easy way to reduce your overall calorie intake. : Prioritizing stress-management and sleep can help regulate the hormones that influence hunger and fat storage. Aim for seven to nine hours of sleep per night and find healthy ways to manage stress, such as restorative exercise, meditation or hobbies outside of work.
: While it’s not necessary to count calories obsessively, having a general idea of how many you’re consuming can be helpful, especially if you’re not seeing the results you want. There are many apps and tools available to help you track your food intake. Grab our CAP Calculator (free at mitchcalvert.
com/calculator) to get an accurate estimate of where your calories and proteins should be to lose, gain or maintain weight. Monday mornings The latest local business news and a lookahead to the coming week. “Calories in, calories out” is a simple concept that provides a good starting point for understanding weight management.
But the human body is a complex system influenced by many factors. Recognizing this complexity can help you make more-informed decisions about your diet and lifestyle. In the end, calories do count — but how your body processes those calories can vary depending on a range of factors, from hormones to gut health to psychological well-being.
By taking a more holistic approach to your health, you can optimize your calorie intake and expenditure in a way that works best for your unique body. So, while the science of weight loss might not be as simple as “calories in, calories out,” it’s still crucial to be mindful of your calorie balance — and to remember that small, consistent changes can lead to significant results over time. Mitch Calvert is a Winnipeg-based fitness coach who has helped more than 1,600 people transform their bodies and lives over the past decade.
Visit mitchcalvert.com/calculator to get a free custom plan — complete with calorie targets and meal ideas — personalized for your age, body weight and goals. Mitch Calvert is a Winnipeg-based fitness coach for men and women like his former self.
Obese in his 20s, he lost 60 pounds himself and now helps clients find their spark and lose the weight for life. Our newsroom depends on a growing audience of readers to power our journalism. If you are not a paid reader, please consider .
Our newsroom depends on its audience of readers to power our journalism. Thank you for your support. Mitch Calvert is a Winnipeg-based fitness coach for men and women like his former self.
Obese in his 20s, he lost 60 pounds himself and now helps clients find their spark and lose the weight for life. Our newsroom depends on a growing audience of readers to power our journalism. If you are not a paid reader, please consider .
Our newsroom depends on its audience of readers to power our journalism. Thank you for your support. Advertisement Advertisement.
