Key steps for women to lose weight: Mastering the calorie formula for accurate fat reduction calculation

The first step to weight loss: Learn to calculate the "calorie formula"

Many people understand the principle of weight loss: when calorie intake is less than calorie expenditure, a person will lose weight. To clearly understand your weight loss progress, you should know how many calories you consume and how many calories you burn each day.

Intake is easy to calculate; simply add up the calories from all your food throughout the day. However, calculating expenditure is more complicated.

I've seen some doctors advise people to diet like this: "A normal person burns 1800 kcal a day (1 kcal = 4186 joules, 1800 kcal = 7535 kilojoules). You're currently consuming more than you're burning, no wonder you're gaining weight."

1800 kcal—many women know this number, but is it accurate? No. Using shampooing as an analogy, people with long hair will definitely use more shampoo than those with short hair. Similarly, overweight people will definitely burn more calories than thinner people. In reality, everyone's daily calorie expenditure is different. To understand this, we first need to know the components of calorie expenditure.

A person's daily calorie expenditure mainly consists of three parts: basal metabolic rate (BMR), energy expenditure from exercise, and the thermic effect of food (TEF), which is the energy consumed in digesting food. Expressed as a formula:

Daily Calorie Expenditure = Basal Metabolic Rate (BMR) + Energy Expenditure from Exercise + TEF

First, let's define "basal metabolic rate."

When we cook rice in a rice cooker, there's a keep-warm button. Pressing this button keeps the rice warm without burning it. Basal metabolic rate is similar to this keep-warm button; it's used to maintain a person's minimum calorie expenditure level (such as the energy needed to maintain basic metabolism, organ function, and body temperature). When is a person's calorie expenditure at its lowest? It's when they're not doing anything, like sleeping.

How can you tell your daily BMR? The formula for women is as follows:

18-30 years old: Basal metabolic rate (J) = [14.6 × weight (kg) + 450] × 4186
31-60 years old: Basal metabolic rate (J) = [8.6 × weight (kg) + 830] × 4186

Over 60 years old: Basal metabolic rate (J) = [10.4 × weight (kg) + 600] × 4186

The above calculations show how many calories a person burns when at rest.

How are basal metabolic rates measured when a person is active? This portion of energy is called "exercise-induced energy expenditure," and the exact amount depends on the type of activity. From blinking an eye to climbing Mount Everest, all these can be considered exercise. However, it's clear that their calorie expenditure is not on the same level.

There are countless ways to exercise, but most people can only consistently stick to a few. Below, I've listed the calorie expenditure levels of some exercises:

Jogging for 1 hour: 2742 kJ (655 kcal);

Brisk walking for 1 hour: 2311 kJ (552 kcal);

Aerobics for 1 hour: 1507 kJ (360 kcal);

Cycling for 1 hour: 1733 kJ (414 kcal);

Jumping rope for 1 hour: 3349 kJ (800 kcal);

The third calorie expenditure indicator is the "thermic effect of food," which refers to the calories needed to digest food. After the body eats, digestion isn't immediately apparent, but the digestive system is constantly working. This work requires calories, which is why we sweat more when we eat. This is relatively easy to calculate and is usually 10% of the "basal metabolic rate."

After learning how to calculate calorie expenditure, you might think that weight loss is simply about reducing calorie intake to lower calorie expenditure, which is roughly true. However, for accuracy, you also need to calculate the conversion rate of calories to fat.

Nutritionalally, it's believed that 32,231 kilojoules (7,700 kilocalories) are needed to burn 1 kilogram of fat.

In other words, to lose 1 kilogram of fat (note, not 1 kilogram of body weight), you need to burn 32,231 kilojoules of energy, which is approximately 3.5 days' worth of calorie intake.

Don't get too excited yet. I'm not saying that fasting for 4 days will result in losing 1 kilogram of fat. Fasting for 4 days, while generally not fatal, could lead to exhaustion and hospitalization, let alone weight loss.

As the saying goes, you can't get fat in one bite, and similarly, you can't lose weight in one day. Weight loss must be moderate. Trying to lose weight all at once is suicidal.

So, is it the correct way to lose weight in stages? Add 10 days, making it 14 days. 32231 kilojoules divided by 14 equals 2302. Simply put, this means losing 2302 kilojoules (550 kilocalories) of calories per day, equivalent to walking 4 kilometers slowly, plus eating one less bowl of rice, for 14 days. While it still requires considerable effort, it's at least more realistic.

If extended to 20 days, the daily calorie loss would be 1612 kilojoules (385 kilocalories), requiring even less dieting and exercise, and might not even feel like much trouble.

By now, you should understand that you can create a specific weight loss plan based on your own circumstances. First, measure your current weight and body fat percentage, then set a target weight, calculate how much fat you need to lose, and then consider how many days to divide that fat loss into. Weight loss is, in fact, an art of management.

It's better to be slow than fast. Even if it's slower, you'll still succeed in the end. Being impatient for quick results makes it easy to give up halfway.