What should I weigh at my age? What science says

Is there a reliable weight chart for your age?

No, there is no scientifically reliable weight chart that can exactly determine what an individual should weigh at a certain age.

With increasing age, individual changes occur in body composition, hormonal balance, and lifestyle. A chart based solely on age and body weight does not capture these complex factors and therefore provides a limited picture of what is a healthy weight for the specific individual.

Focusing unilaterally on a static weight chart also risks leading to unrealistic expectations, increased stress, and, in some cases, unsustainable weight loss strategies.

Is BMI (Body Mass Index) a good measure of what you should weigh?

BMI (Body Mass Index) is a useful screening tool for healthcare, but it is a relatively crude measure for you as an individual because it does not take your body composition into account. Your target weight should therefore be guided by your overall health rather than trying to reach a specific category on the BMI scale.

In healthcare, BMI is often used as a first step to classify overweight and obesity. It is calculated by dividing your body weight in kilograms by your height in meters squared (weight / height x height). On a broad population level, a high BMI has a strong correlation with an increased risk of cardiovascular disease, type 2 diabetes, high blood pressure, elevated blood lipids, and certain types of cancer.

However, the limitation for the individual person lies in the fact that BMI does not distinguish between muscle and fat. Two people with exactly the same height, weight, and BMI can have completely different circumstances and health statuses. For example, a person who does a lot of strength training may have an "overweight" BMI that indicates excess weight due to a large muscle mass, without carrying unhealthy amounts of fat. At the same time, another person may have a so-called "normal" BMI, yet carry a dangerously high proportion of fat around the stomach which increases the risk of metabolic diseases.

BMI boundaries according to the WHO:

• BMI under 18.5: Underweight
• BMI 18.5–24.9: Normal weight
• BMI 25–29.9: Overweight
• BMI over 30: Obesity

Calculate your BMI with Yazen's calculator.

How does the interpretation change after age 65?

After approximately 65 years of age, the interpretation of BMI becomes more nuanced. The link between BMI and health risks changes, and a slightly higher BMI is often not associated with increased risk to the same extent as in younger adults. In some studies, a correlation has even been observed between a moderately higher BMI and lower mortality in the elderly, although this should be interpreted with caution.

An important explanation is that muscle mass decreases with age and that low body weight in the elderly is often linked to an increased risk of frailty, falls, and illness. BMI does not capture these changes in body composition.

Therefore, greater importance is placed on factors such as physical function, muscle strength, and weight stability, rather than solely striving for a low BMI.

Why body composition is more important than the scale

Your health is highly affected by your body composition – that is, the distribution between fat mass and fat-free mass (such as muscles, bones, and organs) – rather than solely by your total body weight.

It is possible to have a body weight or a BMI within the normal range, but still have an increased risk of disease if the fat mass is unfavourably distributed. Particularly significant is visceral fat, also called belly fat. This fat is stored around the internal organs in the abdominal cavity, such as the liver and intestines, and is metabolically active.

Visceral fat is associated with increased production of inflammatory signaling substances and can contribute to low-grade inflammation as well as impaired insulin sensitivity. This increases the risk of cardiometabolic diseases such as type 2 diabetes and cardiovascular disease.

At Yazen, we therefore work on improving body composition, not just reducing body weight. The goal is to preserve muscle mass through adequate nutritional intake and strength training, while the treatment is directed towards reducing the excess-related fat mass in obesity.

How age affects your weight and metabolism

With increasing age, a gradual decrease in muscle mass occurs, a condition termed sarcopenia. This contributes to a lower basal energy expenditure and can, in combination with lifestyle factors, increase the risk of weight gain if the energy balance is not adjusted.

However, it is important to understand that age-related weight gain is rarely due solely to a “slower metabolism”. In practice, it is usually a matter of an interaction between biological changes, reduced physical activity, and the fact that energy intake is not adjusted in line with the body's changing needs.

Because muscle mass is more metabolically active than fat mass, changes in body composition can affect energy expenditure over time. When reduced muscle mass is combined with increased fat mass, a condition called sarcopenic obesity can develop. This is associated with impaired physical function, such as reduced strength and endurance, as well as increased strain on joints and negative effects on metabolic health.

In women, hormonal changes also occur in connection with menopause. Decreased estrogen levels are associated with, among other things, altered fat distribution, where a larger proportion of fat is stored centrally in the abdomen. This means an increase in visceral fat, which is linked to an increased risk of cardiometabolic diseases.

Altogether, this underscores the importance of maintaining muscle mass through, for example, strength training, and adapting diet and lifestyle with increasing age.

What is a realistic and healthy target weight?

A realistic and healthy target weight is the weight where you feel strong, healthy, and have energy in everyday life, and where your medical values and body measurements are at a good level.

When treating obesity, science shows that a total weight loss of approximately 10-15% of body weight is a very successful level for achieving major health benefits. Such a reduction is often enough to lower blood pressure, improve blood sugar balance, reduce strain on the joints, and decrease the risk of cardiovascular diseases. Forcing the body to a specific "dream weight" based on old ideals is rarely either healthy or long-term sustainable.

Read more about weight loss, treatment, lifestyle changes, and health in our guides and articles.

Frequently asked questions about weight, age, and BMI

Is it normal to weigh more as you get older?
Yes, a certain weight gain with increasing age is common. This is due to an interaction between biological changes and lifestyle factors. With age, muscle mass decreases (sarcopenia), which contributes to a slightly lower basal energy expenditure. At the same time, physical activity often decreases, while energy intake is not always adjusted accordingly.

To counteract these changes, active lifestyle choices are required. Regular physical activity, especially strength training, can contribute to preserving muscle mass and thereby support energy balance. The composition of the diet and energy intake also play an important role in maintaining a stable weight over time.

Should you stop caring about BMI completely?
No, BMI is still an important starting point within healthcare to assess whether you meet the criteria for medical obesity treatment (which often requires a BMI over 30, or a BMI over 27 in combination with weight-related complications). However, these measurements always need to be supplemented with an individual medical assessment, body measurements, and blood tests to provide a more holistic picture.

When should you seek medical help for your weight?
If you have a BMI classified as obesity (over 30) and you struggle to lose weight despite repeated attempts with diet and exercise, it may be time to look into the possibility of getting help with modern medical treatment. The same applies to a BMI ≥ 27 in combination with weight-related diseases such as type 2 diabetes, hypertension, or sleep apnea. Obesity is a complex, chronic disease with biological drivers that often require more than just lifestyle advice. A medical investigation can help identify individual circumstances and enable a structured and evidence-based treatment.