How much should you weigh? This is a question that millions of people ask themselves, driven by the desire to feel well, to be in shape, or simply to have an objective reference point. The concept of "ideal weight" has been studied for over a century by doctors, statisticians, and nutritionists, giving rise to numerous formulas and tables. But which formula is most reliable? Is ideal weight really a fixed number? In this comprehensive guide, we will analyze the main formulas for calculating ideal weight, reference tables for men and women, and the factors that make each person unique.
What Is Ideal Weight
Ideal weight (or desirable weight) is the body weight that, for a given height, is associated with the lowest risk of disease and the highest life expectancy. It is not a fixed, precise number, but rather a range within which the body functions at its best.
It is important to distinguish between different related concepts:
- Theoretical ideal weight: calculated using mathematical formulas based on height
- Comfortable weight: the weight at which you feel good physically and psychologically
- Healthy weight: the weight range associated with optimal health indicators (blood pressure, blood sugar, cholesterol)
- Aesthetic weight: the weight perceived as ideal from an appearance standpoint, influenced by culture and trends
Ideally, all these values should converge, but in reality they can diverge significantly. For a healthy approach, healthy weight should be the primary reference.
Formulas for Calculating Ideal Weight
Over the years, several formulas have been developed. Here are the most well-known and widely used.
Lorenz Formula
Developed in 1929, it is one of the simplest and most widespread in Europe:
Men: Ideal weight = height (cm) - 100 - [(height - 150) / 4]
Women: Ideal weight = height (cm) - 100 - [(height - 150) / 2]
Examples:
- Man 178 cm tall: 178 - 100 - (28/4) = 78 - 7 = 71 kg
- Woman 165 cm tall: 165 - 100 - (15/2) = 65 - 7.5 = 57.5 kg
- Man 185 cm tall: 185 - 100 - (35/4) = 85 - 8.75 = 76.25 kg
- Woman 170 cm tall: 170 - 100 - (20/2) = 70 - 10 = 60 kg
Broca Formula
The simplest formula of all, devised by French surgeon Paul Broca in 1871:
Ideal weight = height (cm) - 100
In the corrected version (with a 5-10% correction):
Men: Ideal weight = [height (cm) - 100] x 0.90
Women: Ideal weight = [height (cm) - 100] x 0.85
Examples:
- Man 180 cm tall: (180 - 100) x 0.90 = 80 x 0.90 = 72 kg
- Woman 165 cm tall: (165 - 100) x 0.85 = 65 x 0.85 = 55.25 kg
BMI-based formula
Starting from the normal weight BMI range (18.5-24.9), the ideal weight range can be calculated:
Minimum weight = 18.5 x height (m)^2
Maximum weight = 24.9 x height (m)^2
Average ideal weight = 22 x height (m)^2
Examples:
- Man/Woman 170 cm tall: average ideal weight = 22 x (1.70)^2 = 22 x 2.89 = 63.6 kg (range: 53.5 - 72.0 kg)
- Man/Woman 180 cm tall: average ideal weight = 22 x (1.80)^2 = 22 x 3.24 = 71.3 kg (range: 59.9 - 80.7 kg)
Devine Formula (1974)
Widely used in medical settings, especially for drug dosing:
Men: Ideal weight = 50 + 2.3 x [(height in cm - 152.4) / 2.54]
Women: Ideal weight = 45.5 + 2.3 x [(height in cm - 152.4) / 2.54]
Examples:
- Man 175 cm tall: 50 + 2.3 x (22.6/2.54) = 50 + 2.3 x 8.9 = 50 + 20.47 = 70.5 kg
- Woman 165 cm tall: 45.5 + 2.3 x (12.6/2.54) = 45.5 + 2.3 x 4.96 = 45.5 + 11.4 = 56.9 kg
With our ideal weight calculator, you can get the results of all these formulas simultaneously, comparing them for a complete picture.
Ideal Weight Table for Men
| Height | Lorenz | Corrected Broca | BMI 22 | Normal weight range |
|---|---|---|---|---|
| 165 cm | 61.3 kg | 58.5 kg | 59.9 kg | 50.4 - 67.8 kg |
| 170 cm | 65.0 kg | 63.0 kg | 63.6 kg | 53.5 - 72.0 kg |
| 175 cm | 68.8 kg | 67.5 kg | 67.4 kg | 56.7 - 76.3 kg |
| 178 cm | 71.0 kg | 70.2 kg | 69.7 kg | 58.6 - 78.9 kg |
| 180 cm | 72.5 kg | 72.0 kg | 71.3 kg | 59.9 - 80.7 kg |
| 183 cm | 74.8 kg | 74.7 kg | 73.7 kg | 62.0 - 83.4 kg |
| 185 cm | 76.3 kg | 76.5 kg | 75.3 kg | 63.3 - 85.2 kg |
| 190 cm | 80.0 kg | 81.0 kg | 79.4 kg | 66.8 - 89.9 kg |
Ideal Weight Table for Women
| Height | Lorenz | Corrected Broca | BMI 22 | Normal weight range |
|---|---|---|---|---|
| 155 cm | 52.5 kg | 46.8 kg | 52.9 kg | 44.4 - 59.8 kg |
| 158 cm | 54.0 kg | 49.3 kg | 54.9 kg | 46.2 - 62.2 kg |
| 160 cm | 55.0 kg | 51.0 kg | 56.3 kg | 47.4 - 63.7 kg |
| 163 cm | 56.5 kg | 53.6 kg | 58.5 kg | 49.2 - 66.2 kg |
| 165 cm | 57.5 kg | 55.3 kg | 59.9 kg | 50.4 - 67.8 kg |
| 168 cm | 59.0 kg | 57.8 kg | 62.1 kg | 52.2 - 70.3 kg |
| 170 cm | 60.0 kg | 59.5 kg | 63.6 kg | 53.5 - 72.0 kg |
| 175 cm | 62.5 kg | 63.8 kg | 67.4 kg | 56.7 - 76.3 kg |
Comparing Formulas: Which One to Choose?
As shown in the tables, different formulas give different results. Here is a comparison for a man 180 cm tall:
| Formula | Ideal weight | Notes |
|---|---|---|
| Lorenz | 72.5 kg | Conservative value, good for average builds |
| Corrected Broca | 72.0 kg | Very similar to Lorenz, slightly simplified |
| BMI 22 | 71.3 kg | Based on epidemiological evidence |
| Devine | 75.0 kg | Tends to give slightly higher values |
| BMI Range | 59.9 - 80.7 kg | The most complete and realistic range |
The advice is not to fixate on a precise number, but to consider the normal weight range (BMI 18.5-24.9) as a reference, taking into account your body frame and level of physical activity.
Factors That Influence Ideal Weight
Ideal weight is not determined solely by height. Several factors make each person unique:
Bone structure (body frame)
Body frame is assessed by measuring wrist circumference:
| Body frame | Men's wrist | Women's wrist | Effect on weight |
|---|---|---|---|
| Small (ectomorph) | < 16.5 cm | < 14 cm | Ideal weight in the lower range |
| Medium (mesomorph) | 16.5 - 17.5 cm | 14 - 16.5 cm | Ideal weight in the middle range |
| Large (endomorph) | > 17.5 cm | > 16.5 cm | Ideal weight in the upper range |
A person with a large frame will naturally weigh more than one with a small frame at the same height, without this indicating overweight.
Body composition
Two people of the same weight and height can have radically different body compositions. A man weighing 80 kg with 15% body fat is in very different condition from one weighing 80 kg with 30% body fat. Muscle mass is denser and heavier than fat: a muscular athlete may weigh more than their theoretical "ideal weight" while being in perfect health.
Age
As we age, body composition changes: muscle mass is lost (sarcopenia) and fat tends to accumulate. As mentioned in the BMI section, in elderly individuals a weight slightly above the "ideal" range can be protective. Traditional formulas do not account for age.
Sex
Women naturally have a higher body fat percentage than men (essential for hormonal and reproductive functions). A woman with 25% body fat is in good shape, while a man with the same percentage is borderline overweight. Sex-specific formulas partially account for this difference.
Physical activity level
Athletes, particularly those who practice strength sports, have above-average muscle mass and may legitimately weigh more than the "ideal weight" calculated by formulas. A rugby player 185 cm tall and weighing 100 kg can be in excellent athletic shape despite a BMI of 29.2 (theoretically overweight).
Limitations of Ideal Weight Formulas
It is essential to understand the limitations of all formulas:
- They do not consider body composition: they do not distinguish between fat mass and lean mass
- They do not consider age: with the exception of the BMI method, formulas do not account for aging
- They are based on statistical averages: they derive from population studies, not individuals
- They can create unrealistic expectations: an "ideal" number can generate anxiety and eating disorders
- They do not distinguish body frames: Lorenz and Broca give a single value, regardless of bone structure
- They may be outdated: formulas developed in the 19th century are based on demographic data very different from the current population
Beyond Weight: More Comprehensive Health Indicators
For a more accurate assessment of your health status, it is useful to also consider:
- Waist circumference: indicator of visceral fat (risk if > 94 cm men, > 80 cm women)
- Body fat percentage: measurable with bioelectrical impedance analysis or skinfold calipers
- Waist-to-height ratio: should remain below 0.5
- Blood parameters: blood sugar, cholesterol, triglycerides, blood pressure
- Functional capacity: strength, endurance, flexibility, balance
- Psychological well-being: your relationship with your body and food
A modern approach to health does not focus on a number on the scale, but on a set of indicators that reflect the overall well-being of the person.
Frequently Asked Questions
What is the ideal weight for a man 175 cm tall?
According to the Lorenz formula: 68.8 kg. According to BMI 22: 67.4 kg. The normal weight range (BMI 18.5-24.9) is 56.7-76.3 kg. For a personalized result, use our ideal weight calculator.
What is the ideal weight for a woman 165 cm tall?
According to Lorenz: 57.5 kg. According to BMI 22: 59.9 kg. Normal weight range: 50.4-67.8 kg. The variability depends on body frame and body composition.
Does ideal weight change with age?
Classic formulas do not consider age, but modern research suggests that as we get older, it is healthy to weigh slightly more than the "ideal" values from the formulas. For those over 65, a BMI of 23-27 is associated with the best survival outcomes.
How much should a 16-year-old boy weigh?
For adolescents, adult formulas are not used. Growth curves (percentiles) specific to age and sex are referenced instead. The pediatrician is the reference figure for evaluating growth. Generally speaking, a 16-year-old boy who is 175 cm tall should weigh between 55 and 75 kg depending on physical maturation.
Is it better to weigh yourself every day?
Body weight naturally fluctuates by 0.5-2 kg during the day and from one day to the next, due to hydration, intestinal contents, menstrual cycle (in women), and other factors. To monitor the real trend, it is advisable to weigh yourself once a week, always at the same time (preferably in the morning on an empty stomach), and observe the moving average over 4 weeks.
Can I reach my ideal weight without dieting?
If the difference is minimal (3-5 kg), adopting healthier eating habits (more vegetables, fewer processed foods, controlled portions) and increasing daily physical activity (walking more, using the stairs) may be sufficient without following a structured diet. For larger differences, a personalized meal plan with a nutritionist is the best choice.
How is ideal weight calculated during pregnancy?
During pregnancy, the concept of ideal weight does not apply. Instead, recommended weight gain is discussed based on pre-pregnancy BMI: underweight (12.5-18 kg), normal weight (11.5-16 kg), overweight (7-11.5 kg), obese (5-9 kg). The gynecologist monitors weight gain at each visit.
Lascia un commento