The ideal weight for a man measuring 1.70m depends on the formula used, and each formula is based on different assumptions. The body mass index places the so-called “normal” range between 18.5 and 24.9, which results in a nearly twenty-kilogram gap between the lower and upper limits for this height. Understanding what each method measures allows one to know which to take seriously.
Waist circumference and BMI: two measurements that tell different stories
The BMI divides weight in kilograms by the square of height in meters. For a man of 1.70m, a BMI of 22 corresponds to a weight of about 63.5 kg. This calculation does not distinguish between fat and muscle mass, which is its main limitation.
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Recent tools for calculating healthy weight increasingly incorporate waist circumference as a standalone criterion. According to Index Santé, a high waist circumference increases cardiovascular risk even when BMI remains within the normal range. For a man of 1.70m with a correct BMI, this data can completely change the interpretation of the result.
In practical terms, determining the ideal weight for a man 1.70m requires at least cross-referencing these two indicators rather than relying on a single number on the scale.
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Lorentz formula and Devine formula: calculations and limitations for 1.70m
Two formulas consistently appear in online calculators. They deserve to be understood before being applied.
The Lorentz formula, attributed to a Belgian doctor and dating back to 1929, proposes for a man: (Height in cm – 100) – ((Height in cm – 150) / 4). Applied to 1.70m, it gives a theoretical ideal weight of 65 kg.
The Devine formula, published in 1974, was originally designed to calculate medication dosages, not to define a weight goal. However, it is used by many websites. For a man, the calculation starts at 50 kg for the first 152 cm, then adds about 2.3 kg for each additional 2.54 cm.
These two formulas ignore age, body shape, and body composition. They produce a single number that does not reflect the diversity of bodies. A very muscular man of 1.70m and a sedentary man of the same age get the same result, which poses an obvious relevance issue.
Why the Creff formula adds morphology
The Creff formula attempts to correct this flaw by incorporating a coefficient based on whether the person has a fine, normal, or large bone structure. It also takes age into account. The result therefore varies for two men of 1.70m who do not have the same build, making it theoretically more realistic.
In practice, no formula replaces a complete health assessment. Self-evaluation of body shape (fine, normal, large) remains subjective and introduces a bias into the result.
BMI and ethnic origin: the same number, different risks
Since 2022, several scholarly societies have pointed out that a “normal” BMI does not correspond to the same level of metabolic risk depending on ethnic origin. The thresholds of 18.5 and 24.9 were established based on Western populations. For some populations in South or East Asia, the risk of type 2 diabetes appears at a lower BMI than the threshold considered “overweight” in Europe.
For a man of 1.70m, this means that the ideal weight calculated by BMI may underestimate a real risk. Current recommendations suggest adjusting the thresholds based on the overall clinical context, not just the weight-to-height ratio.
Stability weight: a more reliable indicator than calculated ideal weight
Cohort studies published in recent years shift the debate from “ideal weight” to stability weight. A man of 1.70m who spontaneously maintains a stable weight, without restrictive dieting, and who has good health markers (blood sugar, blood pressure, lipid profile, physical capacity) has a better prognosis than a man who fluctuates around a difficult-to-maintain “ideal” theoretical weight.
Repeated weight fluctuations, often linked to yo-yo dieting, generate documented metabolic stress. The weight on the scale matters less than its stability over time and the associated biological parameters.
What geriatrics changes after 65
Recent work in geriatrics, particularly those reported by HAS and gerontology societies between 2022 and 2024, reminds us that from around 65 years old, aiming for the ideal weight calculated by BMI can be counterproductive. A slight overweight according to standard criteria is associated with better resistance to acute illnesses and hospitalizations in older adults.
For a man of 1.70m over 65, trying to reach the 65 kg of the Lorentz formula may therefore represent a risk rather than a benefit.
Criteria to cross-reference for evaluating health weight at 1.70m
Rather than relying on a single number, a serious assessment combines several parameters:
- BMI as a quick first reference, keeping in mind that it does not distinguish between fat mass and lean mass
- Waist circumference, considered by several recent recommendations as more predictive of cardiovascular risk than weight alone
- Weight stability over time, associated with a better overall prognosis than frequent variations
- Biological markers (fasting blood sugar, lipid profile, blood pressure), which reflect real health status regardless of the number displayed on the scale
The calculation of ideal weight for a man of 1.70m gives a range, not a single target. The Lorentz or Devine formulas provide a starting point, but waist circumference, age, and blood tests tell a more complete story. A stable number accompanied by good biological markers remains, to date, the best available indicator.