How to know your ideal weight

The "ideal weight" is an attractive but misleading concept. There is no magic number that works for everyone. Several formulas give different estimates, and the real question isn't "how much should I weigh?" but "what weight allows me to live healthily, with energy, and without frustration?". This guide compares the formulas and helps you define a goal that makes sense.

Steps

1

Choose a reference formula

The Lorentz formula is the simplest (based on height and sex). The Devine formula is used in pharmacology. The Creff formula adds body type (slender, average, heavy-set). None are perfect — each gives a different range.

2

Enter your parameters

All formulas require at least your height and sex. Creff adds age and body type. The more information you provide, the closer the estimate gets to reality — but it remains an estimate.

3

Compare results from different formulas

For a 165 cm woman, Lorentz might give 56 kg, Devine 57 kg, and Creff 58 kg (average body type). The difference is usually 2-5 kg between formulas. Look at the range rather than a single number.

4

Consider your body composition

Two people with the same "ideal weight" can have very different bodies. A muscular person will weigh more than a sedentary person of the same height, and that's normal. Body fat percentage is a more relevant indicator than weight alone.

5

Set a realistic and personal goal

Your healthy weight is where you feel good, where your blood tests are good, and where you have the energy for your activities. It doesn't necessarily match a formula's number. Aim for a 3-5 kg range rather than a specific figure.

Comparison of different formulas

The Lorentz formula (1929) is the best known: Weight = Height (cm) - 100 - (Height - 150) / 4 for men, / 2.5 for women. The Devine formula (1974) was created for drug dosing, not nutrition. The Creff formula incorporates body type, making it more nuanced. None have been validated as reliable health predictors — they provide benchmarks, not medical goals.

Why a single number doesn't exist

Ideal weight depends on genetics, muscle mass, bone density, visceral fat levels, and even weight history. Two people of the same height and age can have healthy weights that differ by 10 kg. Formulas don't account for these individual factors. They provide an average statistical benchmark, useful as a starting point but insufficient as a final goal.

Setting a healthy and sustainable goal

A realistic goal is a weight you can maintain without excessive restriction, where your health parameters are good, and where you have enough energy to live normally. Start by aiming for a 5-10% loss of your current weight if you are overweight — this is the threshold where health benefits become measurable. Then re-evaluate. A weight that's been stable for 6 months is better than an "ideal" weight that's impossible to maintain.

FoodCraft Tip

Multi-formula ideal weight calculator

The FoodCraft calculator compares Lorentz, Devine, and Creff side-by-side for your profile. You immediately see the range and can make an informed choice for your goal.

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Frequently Asked Questions

Is the Lorentz formula reliable?
It provides an acceptable ballpark figure for a person of average body type. But it dates back to 1929, doesn't account for muscle mass, and underestimates the healthy weight of athletic people. Use it as a benchmark, not as gospel.
Is my ideal weight the same at 25 and 55?
No. As you age, you naturally lose muscle mass and bone density decreases. A slightly higher weight after age 50 is normal and often healthy. The Creff formula is the only one that incorporates age.
How do I know if I'm at my healthy weight?
Ask yourself these questions: Do you have energy every day? Are your blood tests good? Do you maintain this weight without extreme effort? If so, you are likely at your healthy weight, regardless of what any formula says.
Are ideal weight and BMI the same thing?
No. BMI measures a weight-to-height ratio and provides a category (normal, overweight, etc.). Ideal weight aims for a specific number via a formula. Both are approximations with similar limitations.

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