Reduction diet – before you decide

A weight-loss diet is recommended for people who are overweight, obese, or obese. Perhaps not everyone realizes that obesity is a disease. In the International Classification of Diseases (ICD), used by doctors, it has a specific number (E-66). It is defined as the excessive accumulation of body fat.

If you think of yourself as "big boned," you're mistaken. An obese person has more body fat than someone of a healthy weight.

Below are the results of body composition analyses for two young men of similar height. One weighs 80 kg (a healthy weight), the other 150 kg. Neither man's bone mass exceeds 10 kg, but there's a dramatic difference in body fat percentage (18% vs. 34%).

How to check your body weight?

Before you decide to go on a weight-loss diet , check your current weight. There are a few simple ways to do this.

1. Calculation of BMI (Body Mass Index) and its interpretation based on the classification below:

Underweight < 18.5
Normal body weight 18.5 – 24.9
Overweight 25 – 29.9
Obesity ≥ 30
Class I obesity 30 – 34.9
Class II obesity 35 – 39.9
Class III (severe) obesity ≥ 40
e.g. if you weigh 70 kg and are 165 cm tall, your BMI is 25.7 kg/m2 and suggests overweight

2. You can measure your waist circumference.

Weight loss is particularly recommended for women ≥ 88 cm and men ≥ 102 cm. Ideally, waist circumference should not exceed 80 cm for women and 94 cm for men.

3. You can also perform a body composition analysis on a professional device.

This analysis provides detailed information about your body composition. It allows you to assess not only your weight but also body fat, lean body mass, hydration, muscle mass, and bone mass. The device typically also calculates your body mass index (BMI), assesses your basal metabolic rate and energy needs, and provides your metabolic age.

How many kilocalories do I need per day?

Your total energy requirement, or the number of kilocalories you need per day, depends on several factors, including gender, age, weight and height, and physical activity. It can be calculated using the formulas below.

If your BMI is 25 or higher, your daily calorie intake should be reduced by approximately 500-800 kcal compared to your total needs. This will help you lose weight in a SAFE and HEALTHY way. Remember, the goal is SLOW and GRADUAL weight loss, averaging 0.5-1 kg per week.

Step 1 – Begin by calculating your basal metabolic rate (BMR). It's important to note that these formulas only provide an indirect way to determine energy needs and don't take into account other factors that may influence metabolism (including health status, genetic factors, physiological condition, ambient temperature, nutritional status, etc.). I suggest using the Mifflin-St. Jeor formula. This formula takes into account gender, current weight, height, and age.

PPM for women = (10 x current body weight [kg]) + (6.25 x height [cm]) – (5 x age [years]) – 161
PPM for men = (10 x current body weight [kg]) + (6.25 x height [cm]) – (5 x age [years]) + 5

e.g. BMR of a 50-year-old woman weighing 90 kg and 165 cm tall is 1520 kcal
(10 x 90) + (6.25 x 165) – (5 x 50) – 161 = 900 + 1031 – 250 – 161 = 1520 kcal

Step 2 – Multiply your calculated basal metabolic rate (BMR) by your Physical Activity Level (PAL) based on your physical activity level. This will give you your total energy needs.

1.2 – 1.3 low physical activity, no additional exercises
1.4 – 1.5 additional, not very intense, slight physical activity
1.6 – 1.7 work requiring additional physical activity
1.8 – 1.9 standing work
2.0 – 2.4 heavy physical work

For example, the woman described above has a sedentary job and does not exercise (we multiply 1520 kcal x a factor of 1.3). Her total energy requirement is 1976 kcal.

Step 3 – Reduce your total energy needs by approximately 500-800 kcal to achieve a calorie deficit and gradually reduce your weight

e.g. the woman described above should aim for a calorie diet of 1200-1500 kcal to lose weight.

Author of the text:

Dietitian Natalia Parulska, M.A