Debunking Myths Around Weight-Loss: How Losing and Gaining Weight Really Works

Carolies Eaten = Calories Burned + Fat

Unlimitix has delved deep into the science of nutrition and with this article, I plan to debunk several myths around how we gain or lose weight. The science behind this phenomenon is fairly conclusive, suggesting a set of very clear rules to follow. If you’re interested in the science of calories and gaining or losing weight, I highly recommend the first two sections of this article. If you’re merely interested in strategies that help you lose or gain weight when applied, the third and fourth section of this article will be enough.

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1. Calorie balance is all that matters

In physics, Calvin’s first principle states that you can’t create energy. You can convert different types of energy into each other, such as energy of movement (kinetic) into heat (thermal). The intuition behind this is easy to understand. Imagine you fuel up your car with 20 litres of gasoline and drive it with a consistent speed until the fuel tank is empty. Next time, when you fuel the car up with 25 litres and drive the same distance with the same speed, there will be a leftover of fuel or potential energy respectively. It doesn’t matter when you fuel the car up or whether you split the process into filling up five litres at five different points in time. You might laugh at this example. It’s easy enough to be understood by a five-year-old. But why then do so many believe things would be different when it comes to our bodies?

Indeed, exactly the same happens in our body. When there is a leftover of energy, that is, we eat more than we burn, our body converts it into fat. This is an evolutionary important process. Every bit of additional energy is stored in fat cells so that our body can break it down and make use of it when necessary. Many suggest that gaining or losing weight is not only influenced by the absolute number of calories, but also by the timing of our meals and the specific combination of dishes we consume despite them having the same calories. This is illogical. You can either fuel your car up entirely or do so at 5 different points in time. As long as you use the same amount of fuel, nothing will change and you will still be able to drive the same distance.

The calorie is nothing more than a measure of energy, such as kilojoule (kJ). It was firstly introduced by Nicolas Clement in 1819 as a unit of heat energy and later the use of kg-calories was introduced brought to the realms of nutrition by Wilbur Olin Atwater. Today, kJ is the most common measure of energy, while calories are only used to describe the nutritional energy value of food. Remember that food can be seen as nothing else but energy that your body can use. Dietary fibre and water don’t have any energy value, but proteins, carbs, fats and alcohols do. Those are called macro-nutrients and they’ll be explained in our next article. [1]

Several studies show that the amount of calories consumed is all that matters for either losing or gaining weight [2][3][4][5][6], that is:

Calories eaten = Calories burned + Fat

In short, if we consume more calories than we burn, we gain weight as additional calories will be transformed into fat. When we consume less calories than our body burns, it will convert fat cells into energy. Studies suggesting otherwise usually rely on inaccurate data aggregation tactics, such as food journals. However, while the “calories eaten” part of the equation is incredibly simple, the “calories burned” part is a little bit more complicated.

Calories out

Our body needs energy to function and there are three different types that play a role:

1. Your basic metabolism (BMR): Simply put, this is your body keeping you alive. Every day, we need to maintain a certain heartbeat, allow our brain to navigate us through the complexities of the world and use our organs to store food.

2. Thermic effects of food (TEF): Some food, especially food with more protein sparks your metabolism and thus helps your body digest. This results in more calories being burned and is often referred to as diet induced thermogenesis. Don’t confuse this with the argument that calorie count is not all that matters. Eating more protein does not affect the calories you consume, but the other part of the equation: Calories burned. I’ll come back to this in more detail later.

3. Physical exercise: The more you move, the more calories your body burns. Back to our car analogy from the beginning: If we drive faster or accelerate more during our drive, our car will need more energy during the same amount of time it is driven. This is true for our body, too. If we use it more during the 24 hours of the day, more energy is consumed. [7][8][9][10][11]

Now, as simple as this equation is, how do we measure the calories we burn. After years of nutritional coaching, there is only one way to get it right completely: Rigorous calorie counting and measuring your weight every single day at the same point in time. However, this is not necessary in most of the cases. Simply using an approximation and trying to stay below that approximation if attempting to lose weight helps. For example, this calculator helps you calculate your basic metabolism.

All you need to add is your TEF, using this calculator for instance, and your calories burned through physical exercise, for example by using this calculator. That’s it. Add all of the three together and voilá, that’s the calories you burn every day.

Calories in

Meal and calories tracking is difficult and requires an understanding of macro nutrients, which I will cover in the next article. However, apps such as MyFitnessPal or Chronometer help you get a feeling for the calories you consume.

The gist

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Note that alcohol and water are macronutrients, too, which are neglected for reasons of simplicity.

It is as simple as that. Consume less calories than you burn and you will lose weight. Keep in mind that myriads of fitness books and blog articles still try to claim they know special tips beyond that equation to help you lose weight. There is little to no evidence that meal-timing, ketonic dieting and special food combinations help ordinary people lose weight in the long term. Many argue, for the sake of selling their product, that specific combinations of foods or diets are more effective or ‘overwrite’ the “calories in, calories out” equation. This doesn’t only violate the principles of physics, it also disregards a whole lot of proper A-journal empirical studies. Equipped with the argumentation in this article, you are now immune to those unsubstantial claims.

2. Restrictions to the calories in, calories out theory

The basic hypothesis of that equation, though, is that everything within your body is alright, that is your body should be able to convert all the calories eaten into energy. Exceptions occur if something with your body is wrong, such as having hyperthyroidism — and in such a case I do encourage you to see a doctor.

Firstly, brutal overeating will usually not result in you gaining as much weight as you should when solely looking at the calories consumed. The “calories in, calories out” theory operates under the hypothesis that your body will convert everything that is eaten into energy. However, this is not always the case. Consider you burn 2500 calories a day and consume 12.000 calories tomorrow. Your body will store some of them in fat cells, but excrete the additional calories without doing much. Your body is simply overwhelmed by all the food eaten. However, the chemical process of turning nutritional fat into body fat is fairly easy and should those 10000 additional calories consist of fat, such as olive oil or butter, your body might still be able to transform most of them into body fat. This is especially interesting for people who want to gain weight, rather than lose weight. A rule of thumb is that within a spectrum of +/- 1500 calories, the theory holds accurately. [12]

Secondly, there is partial evidence that eating everything in a single dish, rather than in many single dishes, will increase your TEF and thus the calories your body burns. [10]

Thirdly, beware that health encompasses much more than mere weight. Of course, being heavily underweight or overweight is not healthy, but health goes much further. For instance, consuming all your calories through sugar does not necessarily result in weight-gain, surely even if you stay below the calories burned. However, this may result in unhealthy insulin levels and may eventually even lead to diabetes. Moreover, consuming many other unhealthy substances, such as artificial flavour enhancers, will most certainly trigger negative health effects in the long run. Moreover, consuming too many bad fats may negatively influence your hormone levels.

3. Hacks to lose weight

Many people I coached in the past got angry at the “calories in, calories out” theory. They considered it to be unfair, since some people are hungrier than others and some have a slower metabolism and thus slower digestion. This argument is unsubstantial because not every calorie fills you up to the same extent! I got my coachees to calculate the calorie/saturation ratio for the food they consume most often. It is difficult to measure saturation perfectly, but rating it on a scale from one to ten usually already does the trick. If the calorie/saturation ratio is very high, either because a certain dish or food has many calories or because it doesn’t fill you up properly, you may avoid it; whereas food that fills you up and at the same time has low calories is desirable. An avocado, for instance, has a very high percentage of fats, even though those are good fats, and doesn’t fill you up easily. Thus, it has a high calorie/saturation ratio. You could easily eat 5 avocados, which would result in up to 2000 kcal, while you would most likely struggle to eat the same amount of kcal in plain rice, which would be more than half a kilogram of rice. Usually 100 grams to 200 grams of rice are enough to fill you up. If you’re especially scientifically-inclined, you can also refer to the satiety index [13].

Fuel your thermogenesis: Eat more protein. I especially recommend this tactic because many high protein dishes have a low calorie/saturation ratio. Moreover, eating much protein fuels your metabolism and thus helps you burn even more calories. [14][15] However, don’t do this through protein shakes if you want to lose weight. Since the calories in a protein shake are liquid, your calorie/saturation ratio is again very high. The breakdown is as follows

- 2–3% of energy content of fat is used to digest it

- 6–8% of energy content of carbs is used to digest it

- 25–30% of energy content of protein is used to digest it [12]

This means that only approximately 70% of the calories you consume in proteins are available to build muscle or fat, while 30% of the calories consumed will be used to break down proteins themselves. However, studies show that high protein diets usually result in a maximum of 100 extra calories burned through diet choice. [16][17] To drive this point even further, there are studies that show that merely increasing the protein intake in general will help you lose weight. [18][19]

Again logically belonging to the calorie/saturation ratio hypothesis: Avoid calories in drinks. Yes, that includes juices, soft drinks, milk and shakes. If you want to lose weight, the best way is to drink water, tea and black coffee while consuming all your calories through solid food. There are several studies that show that solid snacks result in more fullness compared to liquid snacks. Scientists believe that the extra chewing time signals fullness to the brain. [20][21][22][23]

Also, you can make use of appetite suppressants such as coffee, green tea and mate tea to lower your appetite. Consuming these substances daily may help you be less hungry and thus indirectly reduces the amount of calories consumed. [24]

Lastly, pay more attention to eating than to physical exercise. Studies suggest that the effects of eating less rather than exercising more are more effective for your endeavour of losing more weight. This is especially interesting, because eating less usually results in less motivation to work out. However, it is still the more effective tactic. [25]

4. Hacks to gaining weight

Gaining weight is just as hard as losing weight, but there are several tactics that help. As Unlimitix digs into the general science and hence abstract principles of how the world works, all the tips given above are reversibly applicable to gaining weight. Firstly, eat food with a high calorie/saturation ratio. That may include ice cream, oily food and avocados. Make sure, however, to not risk your health for the sake of gaining weight. Moreover, you might not want to fuel your thermogenesis too much. While much protein is good for gaining muscle, I advise having a healthy carb/protein ratio not surpassing 2,5g of protein per kg body weight. Consume liquid calories, especially through shakes and juices. Three glasses of multi-vitamin juice a day and one protein shake can result in an additional 600–700 calories without you feeling particularly filled up. Avoid appetite suppressants such as coffee, green tea and mate tea.

Lastly, and this is solely based on my experiences as a coach, gaining weight when exercising physically is much easier despite the extra calories burned. This is because your body will gain additional muscle mass, which is heavier than fat. If you are naturally very thin, consider applying the tricks from above + a rigorous HIT workout routine.

5. The gist

Losing weight is easy and requires more discipline than the usage of overly exotic strategies. The strategies displayed in this article are more than enough to help you lose weight if applied consistently. Focus on consistent application rather than looking for more sophisticated strategies. The next articles will dive deeper into macro- and micronutrients. Those strategies can be considered pro-tips and will cover benefits beyond gaining and losing weight.


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[2] Bradley, U., Spence, M., Courtney, C. H., McKinley, M. C., Ennis, C. N., McCance, D. R., … Hunter, S. J. (2009). Low-Fat Versus Low-Carbohydrate Weight Reduction Diets: Effects on Weight Loss, Insulin Resistance, and Cardiovascular Risk: A Randomized Control Trial. Diabetes, 58(12), 2741–2748.

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[16] Johnston, C. S., Day, C. S., & Swan, P. D. (2002). Postprandial Thermogenesis Is Increased 100% on a High-Protein, Low-Fat Diet versus a High-Carbohydrate, Low-Fat Diet in Healthy, Young Women. Journal of the American College of Nutrition, 21(1), 55–61.

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