amount of calories each day. Some days you'll consume more and some days you'll consume fewer, but for the most part, on average you'll likely consume a similar amount of calories.
Over time, your body adapts by using this average amount of calories to function. So many calories are needed for each specific function of the body.
When you increase activity level and don't adjust your calories or if you decrease your calorie intake, the body still has a minimum requirement, based on your typical eating habits.
When you restrict calories through food, it forces your body to use stored calories from your body (body fat) in order to fuel all of these processes (at least until it adapts by increasing efficiency or reducing calorie burn - this is when you plateau!).
With regards to restricting those calories, carbohydrates are usually a great choice, since they are usually the most abundant macronutrient in people's diets, meaning carbs provide the largest pool of calories to subtract from.
This is in contrast to the other macronutrients such as protein and fat, which typically are consumed less than carbs. Not to mention, maintaining a high level of protein when attempting to lose weight is strongly advised.
In addition to protein being the most thermogenic (requires the largest amount of calories to digest), it's also the most satiating, meaning that you'll feel fuller for longer, making weight loss easy.
So, Do I Need To Remove Carbs?
The short answer is no, but it's not a bad choice. If you consume a fairly high amount of carbohydrates and are looking to drop a few pounds, reducing calories through your carb intake may be an easy decision for you.
Just know that you don't have to. If you already eat a small amount of carbohydrates but still wish to lose weight, you may need to reduce the calories you consume through fat and protein, instead.