When you decide to lose weight, a common problem is converting kilograms or pounds to calories. You want to lose kilograms or pounds of weight – but wherever you go, you see data mentioned in calories.
So, how do you figure out how many calories you need to burn (or not consume through food) if you want to lose a certain amount of weight?
5 Ways to Calculate Calories to Lose Weight
Figure Out How Much Weight You Want to Lose
The first step to calculating the number of calories required to lose weight is to simply get clear about how many kilograms or pounds of weight you want to lose in a certain amount of time. When choosing the amount of weight you want to lose, you must keep in mind that scientists recommend that we not lose more than 2 pounds a week.
If you want to lose weight in a healthy way, then you should not be losing more than 8 pounds of weight a month. That is around 3.62 kilograms of weight a month. The reason you should not decide to lose more than 2 pounds a week is that beyond 2 pounds, your body will start losing muscle (apart from fat).
Calories Required to Be Burnt to Lose Weight
Scientists have found that 1 pound of body fat, when burnt, results in a loss of 3500 kilocalories. This also means that 1 kilogram of body fat, when burnt, results in a loss of 7716 kilocalories. Don’t be worried by the use of the term ‘kilocalories’ here.
The term ‘calorie’ when mentioned with respect to food consumption and exercise is used to refer to a kilocalorie. So, you can say that when we talk about calories lost or gained, we are actually talking about kilocalories. I will refer to what we generally call ‘calorie’ as kilocalorie in the rest of this article. Coming back to the conversion, if 1 kilogram of body fat equals 7716 kilocalories, does that mean that to lose 1 kilogram of weight, you need to burn 7716 kilocalories? Yes, this a correct assumption.
Thus, if John exercises to burn 7716 kilocalories in 10 days, that means he should be losing 1 kilogram of weight provided he does not change his diet. Similarly, if John burns 3500 kilocalories in 10 days, then he should be losing 1 pound of weight if he does not change his diet. The ‘diet’ factor is important here because the formula above is valid only if the diet of the person remains the same.
This formula is valid only in case of kilocalories burnt through exercise and not in the case of kilocalories consumed (or not consumed) through food. To calculate how many kilocalories you need to burn through exercise alone, multiply the number you decided upon in the first step, by 7716 or 3500 (depending on the unit you use). Let us now discuss how to calculate weight gained or weight lost because of increasing or reducing the kilocalories contained in food.
Calories From Food and Weight Loss
When you look at calorific data mentioned on food containers, you may be tempted to use the above formula to understand how much weight loss can occur if you avoid a certain number of kilocalories. Use the new formula mentioned below instead. One kilogram of weight is lost if you remove 9000 kilocalories from your diet. Similarly, one pound of weight is lost if you remove 4082 kilocalories from your diet.
So, if you cut down 500 kilocalories from your diet everyday, you should be losing around 1.7 kilograms of weight every month. That is because 500 kilocalories everyday means 15000 kilocalories every month. When you divide that number by 9000, you get 1.7. As you can see, more weight is lost when you burn calories through exercise than when you avoid consuming calories.
To calculate how many kilocalories you need to lose through dieting alone, multiply the number you decided upon in the first step, by 9000 or 4082 (depending on the unit you use). Let us now understand how you can correlate both calories lost through exercise, and through diet to weight loss.
Calories Lost Through Dieting and Exercise
Let ‘x’ denote the number of kilocalories lost through exercise and let ‘y’ denote the kilocalories lost through dieting. Then, the amount of weight lost in kilograms will be (x/7716) + (y/9000). Similarly, the amount of weight lost in pounds will be (x/3500) + y/(4082). So, if you burn 1000 kilocalories through exercise and avoid consuming 1000 kilocalories by dieting, you will lose about 0.24 kilograms of weight.
To calculate how many kilocalories you need to lose through both dieting and exercise, divide the number you decided upon in the first step into two parts – weight you want to lose through dieting and weight you want to lose through exercise.
Multiply the amount of weight you want to lose through exercise by by 7716 or 3500 (depending on the unit). This will give you number of kilocalories you need to lose through exercise. Multiply the amount of weight you want to lose through dieting by 9000 or 4082 (depending on the unit). This will give you the number of kilocalories you need to lose through dieting.
The Reason for The Difference in Dieting and Exercise Calories
Why does exercise contribute to a greater loss in weight for the same number of kilocalories lost? The reason is that when we talk about weight loss through exercise, the weight lost is in the form of body fat. Body fat is not pure fat and it contains a certain percentage of other substances other than pure fat.
On the other hand, when we talk about weight gained or weight lost because of the food we eat or don’t eat, we talk about pure fat. The ‘fat’ values you see mentioned on food containers are pure fat values. This difference in the amount of pure fat being talked about results in different weight loss in the case of dieting and exercise for the same amount of kilocalories lost.
Well, now that you know exactly how many calories you need to burn (and reduce from your diet) to lose a certain amount of weight, go ahead and take action! Use the formulae above to understand how many calories you want to lose everyday. If you keep going and lose your target number of calories everyday, you should be on your way towards weight loss soon.