Everyone has been told that calorie-counting is the most effective way of lowering the scale and cutting the kilos.

An average woman is said to require about 2000 calories per day to maintain a certain weight, and 1500 calories to lose almost half a kilo of weight per week. The average male is similar, but slightly raised: he needs 2500 calories to maintain, and 2000 to lose that half-kiloof weight per week. The general rule of thumb deemed by society is to exercise more and eat less.

However, the math is not quite that simple. These rough estimations don’t consider numerous factors that would significantly sway the numbers: age, height, weight or activity levels. While you may think that frequent exercise is the best way to lose weight, it is not a transmutable technique for eating smart.

Fortunately, calorie counting doesn’t have to be a total guessing game. Instead of using exercise as a mere safety net for your eating habits, use this elementary equation to pinpoint exactly how many calories you need per day.

The calculation is called the Mifflin-St Jeor equation, a formula that has been shown to be the most accurate way of estimating calorie needs in numerous studies by the ADA (American Dietetic Association).

Getting an idea of your basal metabolic rate (BMR)

Begin by getting an idea of your basal metabolic rate (BMR).

Staying alive isn’t an easy task, and it needs calories to do so. This number reflects an estimate of how many calories you would burn if you were to be hypothetically resting in a sedentary state for 24 hours.

In other words, it represents the minimum amount of energy mandated to keep your body barely functioning, i.e. breathing and pumping blood.

For men, the equation is as follows: 10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) + 5. The equation is slightly different for women: 10 x weight (kg) + 6.25 x height (cm) – 5 x age (y) – 161.

For example, if you were a 63kg, 30-year-old, 167cm woman, your BMR calculation would look like this: 10 x (63.5) + 6.25 x (167.6) – 5 x (30) – 161 = 1,371.5.

Use this BMR number as the foundational reference point for safe weight loss. According to the Academy of Nutrition and Dietetics, your calories should never dip below 1,200. Doing so could mean your muscle mass starts decreasing, which means you won’t have enough energy to fuel daily activities.

Now that we’ve figured out the bare minimum of calories your body demands, we can’t forget to account for the actual things you do throughout the day that burn these calories; walking to work, playing sports, doing yoga, or even watching TV all strip away those units of energy you consume.

An easy way to do so is via this interactive calculator from the United States Department of Agriculture (USDA) that incorporates your activity level and BMR to give you an estimate of how much you should eat in order to maintain your current weight.