There is a well-known saying in the fitness world that if you consume fewer calories, you burn fewer calories, and your metabolism slows down. Period. No Ifs and Buts.
Well, they are WRONG!
If understood wrongly, this saying is a SHORTCUT that generalizes things and it can be a myth! Further, other websites do not explain the nuance behind it.
*Note that consumption of fewer calories in this article refers to you consuming fewer calories for a substantial period. I.e. you are on a diet.*
Allow me to delve deeper.
The Answer is Yes and No. You might burn fewer calories if you eat less. But it’s not always the case!
Let’s look into the argument for “Yes”.
In the real world, I find that the answer is a yes. But it’s not an absolute truth! Yet, why is it a yes?
Well, when you consume less, you have less energy. When you have less energy, you tend to move less throughout the day. Simple. This is quite natural.
For example – when exercising, you may not push as hard, you may be less animated when talking to people, and you may even fidget less.
This lesser amount of activity results in fewer calories burnt. This happens at a very subconscious level. It is this reduced activity that fitness people reference when they say your metabolism slows down. But it is a generalization and lacks precision.
We have to take note that it is not the lesser consumption of calories that always and automatically results in fewer calories burnt. It does not just happen. There is a mechanism behind it.
Rather, it is the lesser movement that comes from being in a caloric deficit that causes fewer calories to be burnt.
Thus, this can be overcome by consciously moving more!
Let’s look into the argument for “No”.
In theory, you do not burn fewer calories if you eat less and still move the same amount and have the same weight. (Ignore the thermic effect of food as it is not very significant.)
This is because, If you were to get the same person at equal weight, muscle mass, and fitness level and ask them to jog 2km, both would burn about an equal amount of calories even if one consumed fewer calories. FACT.
Again, this is worth repeating, this means that consuming fewer calories does not automatically reduce your calorie burn.
This only seems the case because consumption of fewer calories results in lesser movement throughout the rest of the day.
You tend to be more tired when you consume fewer calories.
We can use this knowledge!
Since we know that equal amounts of movement burns roughly equal amounts of calories for the same individual, and that we are less likely to move when we consume fewer calories, then we just need to remember to move more when we consume fewer calories!
In this way, we can continue our higher caloric expenditure even when eating fewer calories. Yet, this can be a very difficult task to do.
And that is why I mentioned at the start of the article that in the real world, and in practice, eating fewer calories tends to result in burning fewer calories. But at least you now know the mechanism behind it and can counteract it if you wish to do so.
In conclusion, when on a diet, you do not magically burn fewer calories. You only seem like you burn fewer calories because you tend to be tired and move lesser. To counteract this, consciously move more and be more lively throughout the day!
Fitness IQ +1
If you enjoyed the free article and would like to return the favor to the website, do it by sharing the article with a friend, or liking and subscribing to the blog, or leaving a comment down below! Your help is greatly appreciated. Thank you!
Lean. Fit. You. 