Body Mass Index (BMI): The Comprehensive Guide to a Healthy Weight 2026

Introduction: Why Is Body Mass Index Your First Gateway to Better Health in 2026?

Amid the major health transformation taking place in the Kingdom of Saudi Arabia under Vision 2030, attention to healthy weight has become a necessity rather than a luxury. Obesity and diabetes are among the most prominent health challenges facing Saudi society, as data from the Saudi General Authority for Statistics for 2025 indicates that approximately 59% of adults in the Kingdom suffer from overweight or obesity. This is where the role of the Body Mass Index (BMI) emerges as a quick and simple tool for measuring how well your weight matches your height.

The Body Mass Index is widely used in Saudi health centers, in periodic screening programs offered by the Ministry of Health, as well as in medical assessments for health insurance. Some cooperative insurance companies licensed by SAMA (the Saudi Central Bank) also adopt Body Mass Index as one of the factors in determining health insurance premiums, making an understanding of this indicator a matter with direct financial and health implications.

In this comprehensive 2026 guide, we will explain everything you need to know about the Body Mass Index: from its calculation formula, to its classifications, its relationship to chronic diseases, and its particularities for children and athletes, all the way to practical steps for healthy weight loss. We will also provide you with real-world examples from the Saudi market, and golden tips to help you make informed health decisions. And because manual calculation can be confusing, we recommend using the BMI calculator to get your result in seconds.

Table of Contents

• What Is Body Mass Index?
• BMI Calculation Formula
• Body Mass Index Classifications
• Ideal Weight by Height
• The Relationship Between BMI and Health
• BMI in Children and Adolescents
• BMI for Athletes (Exceptions)
• How to Lose Weight Healthily
• When to Consult a Nutritionist
• Golden Tips
• Frequently Asked Questions

What Is Body Mass Index?

Body Mass Index is a numerical measure used to assess whether a person's weight is appropriate for their height. This index was developed by the Belgian scientist Adolphe Quetelet in the 19th century, and today it has become one of the most widely used tools in the world for assessing the nutritional status of adults. The index is based on a simple idea: body weight should be proportional to the square of height, such that there is neither a deficiency nor an excess that affects health.

The Body Mass Index is widely used in the Kingdom of Saudi Arabia in:

• Periodic examinations in primary healthcare centers.
• Pre-marital screening programs supervised by the Ministry of Health.
• Medical fitness assessments for health insurance at companies licensed by SAMA.
• Occupational health programs in major establishments in accordance with the requirements of the Saudi Labor Law.
• Health promotion initiatives in schools and universities.

Despite its simplicity, the Body Mass Index is not a medical diagnosis in itself, but rather a preliminary indicator that requires a comprehensive assessment including body fat percentage, waist circumference, medical history, and lifestyle. Nevertheless, it remains an excellent tool for beginning your health awareness journey.

BMI Calculation Formula

The value of the Body Mass Index is calculated according to the following formula:

Body Mass Index = Weight (kg) ÷ (Height in meters × Height in meters)

Practical example: If your weight is 80 kg and your height is 1.75 meters, the calculation is as follows:

• Height squared = 1.75 × 1.75 = 3.0625
• Body Mass Index = 80 ÷ 3.0625 = 26.1

This value falls within the overweight range according to World Health Organization classifications.

The imperial system (pounds and inches) can also be used via the formula: Body Mass Index = (Weight in pounds ÷ Height in inches squared) × 703. However, the metric system is the one adopted in Saudi health facilities.

To make things easier, you can use the BMI calculator, which performs the calculation automatically and gives you the appropriate classification along with preliminary recommendations.

It is important to note that the formula provides an approximate figure and does not take into account body fat distribution or muscle mass. Therefore, it is always recommended to combine the result with other measurements such as waist circumference and body fat percentage.

Body Mass Index Classifications

The World Health Organization adopts a standard classification for Body Mass Index values for adults (18 years and older), which is the classification adopted in the Kingdom:

It should be noted that some studies indicate that populations in the Middle East may be more susceptible to health complications at lower index values, so some doctors in Saudi Arabia may adopt a lower threshold for obesity at 27.5 instead of 30 in special cases.

According to Saudi Ministry of Health reports for 2025, approximately 28% of adults in the Kingdom fall within the obesity range (BMI ≥ 30), while about 31% suffer from overweight. These figures are driving health authorities to intensify awareness campaigns on the importance of regularly monitoring Body Mass Index.

Ideal Weight by Height

The ideal weight range can be derived from Body Mass Index classifications. If the healthy range is between 18.5 and 24.9, then the ideal weight for any height is calculated by multiplying the square of the height by these two limits.

Real-world example: A Saudi employee in Riyadh who is 175 cm tall and weighs 90 kg has a Body Mass Index of 29.4 (overweight). His target healthy weight ranges between 57 and 76 kg, meaning he needs to lose about 14 kg to reach the upper limit of the healthy range.

This type of calculation helps employees in both the public and private sectors set realistic goals, especially in light of occupational health programs adopted by some major companies in cooperation with the General Organization for Social Insurance (GOSI) to improve employee productivity and reduce sick leave.

The Relationship Between BMI and Health

The Body Mass Index is closely linked to many health conditions. The higher the index rises above the healthy range, the greater the risk of developing chronic diseases. The most prominent of these diseases include:

• Type 2 diabetes: Ministry of Health data indicates that more than 4 million people in Saudi Arabia have diabetes, most of whom are overweight.
• Cardiovascular diseases: High blood pressure and high cholesterol are directly linked to obesity.
• Joint and bone problems: Excess pressure on the knees and spine.
• Sleep apnea: Common among those with severe obesity.
• Certain types of cancer: Such as colon, breast, and kidney cancer.
• Fertility problems: Obesity affects fertility in both men and women.

A Body Mass Index below 18.5 (underweight) also carries health risks, including weakened immunity, osteoporosis, anemia, and menstrual problems in women.

On the economic level, estimates indicate that obesity costs the Saudi economy billions of riyals annually due to direct health spending and lost productivity, which prompted the Zakat, Tax and Customs Authority (ZATCA) to impose an excise tax on sweetened beverages at a rate of 50% since 2019, as a measure to reduce sugar consumption.

BMI in Children and Adolescents

The Body Mass Index in children and adolescents (ages 2 to 19) is not measured in the same way as for adults. Instead of fixed classifications, what is known as Percentile Growth Charts is used, which take into account age and gender.

The adopted classification for children and adolescents:

• Underweight: Below the 5th percentile.
• Healthy weight: From the 5th percentile to below the 85th percentile.
• Overweight: From the 85th percentile to below the 95th percentile.
• Obesity: 95th percentile and above.

In Saudi Arabia, the Ministry of Health launched the "Rashaqa" program for screening school students, and the 2025 results revealed that approximately 22% of Saudi children in the 6-14 age group suffer from overweight or obesity. This is due to lack of physical activity and increased consumption of fast food and soft drinks.

Therefore, parents are advised to monitor their children's Body Mass Index annually, and to use the BMI calculator specialized for children to determine where the child falls on the percentile chart.

BMI for Athletes (Exceptions)

The Body Mass Index is inaccurate for athletes and bodybuilders, because muscle is heavier than fat. A bodybuilder may have an index of 28 or 29, which is classified as "overweight," while his body fat percentage does not exceed 10%.

In Saudi Arabia, with the growing interest in sports within the "Quality of Life" initiatives, there has become a large number of amateur and professional athletes for whom the index may give misleading results. Therefore, they are advised to use alternative measures such as:

• Body fat percentage via an InBody device.
• Waist circumference (should be less than 94 cm for men and 80 cm for women).
• Waist-to-height ratio (should be less than 0.5).
• Body Composition Analysis.

This also applies to pregnant women, the elderly over 65, and people with a large muscular build. In these cases, the Body Mass Index is merely a starting point, not the final verdict.

How to Lose Weight Healthily

If the result of your Body Mass Index shows that you are in the overweight or obese range, there is no need to worry. Healthy weight loss requires gradual and sustainable lifestyle changes. Here are the essential steps:

1. Set a realistic goal: Losing 5-10% of your current weight within 3-6 months achieves significant health benefits.
2. Adopt a balanced diet