The nutrients contained in the food we eat for example fats and carbohydrates, contain the energy that powers our movements, like walking or running and all the processes to sustain life like our brain and heart function.
The energy contained in these nutrients are what we call calories. Different nutrients contain different amounts of calories in them. 1 gram of protein contains 4 kcal, 1 gram of carbohydrate contains 4 kcal and 1 gram of fat contains 9 kcal.
During the day your body breaks down a number of nutrients in order to release the energy it needs to sustain life (e.g. heartbeat, brain function, digestion) and to power movement (e.g. daily activities or workout). This process is what we all refer to as “Burning calories”.
Whenever we eat more nutrients than our body breaks down OR in other words, we eat more calories than we burn our body stores this excess energy. This is how we gain weight.
On the contrary, whenever we eat less nutrients than our body breaks down OR in other words we eat less calories than we burn, our body faces a deficit. In order to cover it, it goes into its nutrient reserves and draws the energy needed to cover this deficit. This is how we lose weight.
So, creating a deficit of calories (in other words energy) is the ONLY way through which the human body loses weight. That comes with good and bad news. The bad news is that you actually need to eat less than what you burn to lose weight and so secret foods, or exotic combos alone will not help you in any way. The good news is that any type of diet will yield more or less the same result in terms of weight loss. That means that you can absolutely stick to the diet that suits your preferences, as long as it ticks the health requirements we will discuss in subsequent modules and of course as long as you eat fewer calories than you burn.
A recent study conducted at Stanford university revealed exactly that which is also what basic physics informs us. That there is no significant difference in the amount of weight you will lose if you follow a high fat or a high carbohydrate diet. The amount of weight a person loses is simply dependent on how big his or her caloric deficit is. (https://jamanetwork.com/journals/jama/article-abstract/2673150?redirect=true)
As a result, knowing how many calories your body burns every day is essential in order to know how much you need to eat in order to create a sufficiently large caloric deficit. The most accurate way of determining the number of calories a person’s body is burning is through a metabolic analyzer. Ultimately, by knowing how many calories you burn daily you can tailor your nutrition to your personal caloric needs and to your fitness goals.