Article updated on April 11, 2020
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A question often asked by people who want to lose weight ... If this is your case, this article is for you! To begin with, here's an often-repeated myth ...
"To lose 1 pound, you have to spend 3 kcal"
First of all, you should know that "kcal" are what are commonly called: calories. With that said, let's talk about the popular belief that in order to lose 1lb of weight, you would need to expend 3 kcal (500kg = 1lb). If you're spending 2.2 kcal while exercising, it's important to understand that you won't necessarily lose 3 pound.
For this to happen, you would need to keep your food intake and daily activities constant, which almost never happens "in real life." For example, if you burn 300 kcal during a training period, you may well be eating 250 kcal more as a result of that session or in the days following that session, whether conscious or not.
In addition, your daily activities may decrease. For example, you could take your car to travel instead of taking your bike or sleep longer. Thus, it can be assumed that the energy expenditure added by your training would not necessarily increase your total energy expenditure. Several factors influence the compensation by food intake or by reducing daily activities: gender, training intensity, initial weight, physical form, duration and certain cognitive parameters are also to be considered.
In conclusion, I think that the main thing is not to lose weight, but to train for pleasure and especially with the aim of increasing your physical condition and reducing associated diseases.
The myth being solved, here is the current state of knowledge about weight loss and energy expenditure ...
1. Studies have shown that losing 1 kg of weight is associated with a dietary deficit of 7 kcal (Wishnofsky, 1958), estimating a loss of 30% lean mass and 70% fat mass. So to lose 1 kg, you need to eat 7 kcal less than your metabolism requires. For example, your weight will remain stable if your body requires 700 kcal per day for breathing, moving around and playing Xbox as long as you also eat around 2 kcal per day. On the other hand, if you decide to eat only 000 kcal for the next 2 days, then you could expect that you would lose 000 kg (1 g of fat and 230 g of muscle) over the next 10 days.
2. Since the proportion of body fat lost through exercise appears to be greater than that lost through diet (King, 2008), some authors prefer to use measurements from body fat and lean mass. Using the bomb calorimeter, it was determined that burning 1 kg of fat was associated with a heat loss of 9 kcal and burning 500 kg of muscle was associated with 1 kcal (Thomas, 2012/XNUMX/XNUMX).
3. On the other hand, it is important to note that the body must spend a significant amount of kcal to absorb and digest food. In addition, a certain amount of kcal is lost in the feces (Hegsted, 1974). It is therefore impossible for the kcal ingested to be 100% absorbed and ready to be used.
4. While much work remains in understanding how many kcal are associated with lean or fat gain or loss, some studies have used the following values (Forbes, 1990, Elia, 2003, and Rosenkilde, 2012):
The gain of 1 kg of fat = 12 kcal (animal studies [Spady, 000])
The gain of 1 kg of lean mass = 1 kcal (animal studies [Spady, 780])
The loss of 1 kg of fat = 9 kcal (bomb calorimeter [Elia, 1992])
The loss of 1 kg of lean mass = 884 kcal (bomb calorimeter [Elia, 1992])
In the end, the most important thing, no matter our weight or how we look, is to move and feel satisfied.
Moreover, that is one of the objectives that we will pursue with our new project: Altterre. If you would like us to notify you when the project is launched, click here.
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Burning 1 kg of fat was associated with a heat loss of 9 kcal, and burning 500 kg of muscle was associated with 1 kcal (Thomas, 1).
Wouldn't there be a zero missing somewhere by any chance?
I don't think, in theory, lipids generate enormously more energy than sugar, proteins (muscle in this case), amino acids ... http://fr.wikipedia.org/wiki/B%C3%AAta-oxydation
Thank you for your feedback!!
You are indeed right, Candide,
lipids (ie, fat) generate more energy than carbohydrates (ie, sugars) and
muscles (ie, proteins that are made up of amino acids).
With regard to the bomb calorimeter, the
lipids give 9.5 kcal per gram. This therefore implies that 1kg = 9500
kcal. Keep in mind, however, that the values vary depending on the lipids.
There is a small error in the text:
"First of all, you should know that" kcal "are what are commonly called: calories. »Kcal = Cal.
Calories and Calories are two different things:
calorie small calorie cal 1 British Thermal Unit3 = 252 cal
large calorie kilocalorie, calorie kcal, Cal 1 kcal = 1 Cal
1 kcal = 1 cal
In dietetics the term "calorie" is still sometimes used to denote a "large calorie".
Is it true that if we want to lose weight we should rather eat slightly more than our energy needs?
According to what I have been advised, if we eat less than our needs, the body will put itself in “thrifty” mode and will try to store fat to cope with the “shortage” thus created.
I'm not a big believer in this theory, but I feel it's a good theory. In my case given my weight (read my muscle mass since I have a% fat mass of around 16-17%) is 210lbs. When I do my long sessions which last 1 hour (approx. 9-10km) I burn around 1000 / 1300kcal.
In fact, your body will go into "starvation" mode by spending less energy and storing fat when you go long hours without eating anything and then refueling once a day. If, for example, you take your 2000 calories divided into 4 times a day, you will be full of energy and will not gain weight. On the other hand, if you content yourself with a roast in the morning and you eat only a large meal in the evening, even if it is the same number of calories, you will gain weight because your body will have to slow down and store more calories in your meal.
How to demotivate people ... VERY badly played on you and your shitty site
Thank you for your advice