BMI Calculator
What is BMI?
BMI (Body Mass Index) is a method of estimating a person's body fat and assessing whether their weight is within a healthy range.
This is measured by dividing weight (in kilograms) by height in meters squared.
Weight classes for BMI values
Underweight
(BMI below 18,5)
A person with this BMI class weighs less than recommended in relation to their height, which can be a sign of malnutrition or other health problems.
Risk factors:
- Malnutrition
- Decreased muscle mass
- Osteoporps or bone loss
- Weakened immune system
- Anemia
- Fertility problems
- Increased risk of complications during operations
If you are underweight, you should consult with your health care provider and a doctor to determine any underlying health problems and get advice on how to achieve a healthy weight.
Normal weight
(BMI between 18.5 and 24.9)
Try to keep the weight off by eating healthy and exercising every day.
Overweight
(BMI between 25 and 29.9)
An overweight person weighs more than is recommended for their height.
Risk factors:
- Hypertension
- High cholesterol
- Increased risk ofcardiovascular disease
- Higher risk of type 2 diabetes
- Breathing problems(eg sleep apnea)
- Joint pain
If you are overweight, you should consider making lifestyle changes, such as a balanced diet and regular exercise, to reduce the risks associated with being overweight.
Obesity class-1
(BMI between 30 and 34.9)
A person with this BMI has an increased risk of several health conditions compared to those in the overweight or normal weight category.
Risk factors:
- Hypertension
- High cholesterol and triglycerides
- Type 2 diabetes
- Heart diseases
- Stroke
- Certain types of cancer
- Breathing problems(eg sleep apnea)
It is strongly recommended that you consult with a healthcare professional about potential treatment methods and lifestyle changes to improve your health.
Obesity Class-2
(BMI between 35 and 39.9)
This BMI class means a higher risk compared to obesity class 1.
Risk factors:
- Serious cardiovascular diseases
- Increased risk of certain cancers
- Increased risk of early death
- Severe sleep apnea
- Gallbladder problems
Consider immediate lifestyle changes and medical treatment. It is crucial that you consult a healthcare professional.
Obesity Class-3
(BMI 40 or higher)
People with extreme obesity are at an acute risk of serious health problems.
Risk factors:
- Serious cardiovascular diseases
- Diabetes
- Breathing problems,including severe sleep apnea
- Increased risk of most cancers
- Increased risk of early death
- Joint problemsincluding osteoarthritis
- Gallbladder problems
- Fatty liver
It is of the utmost importance that you immediately consult with a healthcare professional and consider medical treatment and other interventions to manage your health.
What is a normal Body Mass Index?
The reference value for normal weight (according to the World Health Organization, WHO) is between 18.5 and 25 (24.9 to be exact!). A BMI over 25 is classified as overweight and a BMI value over 30 as obesity. A BMI below 18.5 is defined as underweight.
The BMI index, however, does not say much about your body composition or what your kilos are made up of, and a higher BMI does not automatically mean a danger to your health. A body with a lot of muscle (large muscle mass) gets a high value, and the same is true if a person has a healthy weight but is relatively short. BMI can therefore be a way to get an idea of what is a suitable body weight for you, but does not have a direct connection to your fat percentage or the percentage of muscle mass in your body. And even if you are considered overweight or obese according to BMI, your body and weight may be healthier than the numbers show. In order to get a better and truer picture of a person's health and risk profile linked to body composition, i.e. the amount of muscle and fat and where the fat is located on the body, more advanced measurement methods are needed.
The same reference value for BMI applies regardless of whether you are a woman or a man, but for children different intervals apply, depending on the child's age. Contact the school health service or children's health service if you want to know more.
For those who have BMI 30, or BMI 27 plus complications or other risk factors it means that you may need medical treatment to support your weight loss. At Yazen have a whole team of committed and dedicated people who can support you along the way. The team includes dietitians, YazenCoaches, doctors, psychologists, personal trainers and digital tools - all to give you a safe and secure weight loss and lasting results.
Measuring the waist (waist circumference) is a good way to supplement the information and find out if the fat is placed in a way that affects the organs of the body.
Abdominal fat is linked to a number of health risks, while fat that sits on the buttocks and thighs usually affects health to a lesser degree. It is mainly diseases and conditions related to metabolism that are affected by your weight and your waist circumference, for example, heart and vascular disease such as high blood pressure (hypertension), high cholesterol and other blood lipid disorders, insulin resistance and elevated blood sugar, type 2 diabetes, sleep apnea, as well as pain in the back, knees and other joints. These symptoms are collectively called the metabolic syndrome, because they are related to the metabolism. Overweight and obesity also increase the risk of certain types of cancer.
Healthy eating habits (a diet that meets your needs and contains a lot of vegetables, fruit, berries, beans, lentils, peas, whole grains, fish, and a limited amount of ultra-processed foods with fast carbohydrates and a lot of fat, salt and sugar) are important, alongside physical activity, preferably in the form of everyday exercise interspersed with tougher training that raises the heart rate a little extra and challenges your muscles.
Having a weight within the normal range is positive for health, but even if you weigh more than that, it is important to have healthy habits, among other things to make you feel good, for the body to function at its best, and to prevent ill-health linked to lifestyle and living habits. If your BMI is below 18.5, it may be good to gain a few kilos in weight, among other things, to maintain health in the long term and to increase the chances of getting all the nutrition the body needs.
BMI in research
Body mass index is also used as a screening tool in research, for example to map the average weight in a population or in certain groups.
For BMI to be more useful and relevant in an individual health assessment, it has to be supplemented with, for example, waist circumference, blood pressure, blood tests and other measurement variables that say more about your habits, health risks and what you can do to influence your health. BMI only shows the relationship between weight and height, and does not take into account other factors that affect your health. One of the most important things you can influence yourself is a healthy diet.
Reference values for BMI
Underweight: under 18,5
Normal weight: 18,5 - 24,9
Overweight: 25 - 30
Obesity class 1: 30–34,9
Obesity class 2: 35–39,9
Obesity class 3: 40 and over
The same reference range for BMI applies to women and men, but not to children. Contact the school health service or children's health services if you want to know more.
Success Stories
For most people, lasting weight loss has been impossible.Until now.
"I really can’t wait to get stuck back in hiking. Mount Kilimanjaro, here I come!"
"With Yazen, I’ve received a level of support I’ve never felt before in anything I’ve gone through in my life."
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Frequently asked questions
Below we list the most frequently asked questions about our service. If you have other questions or concerns, please contact us and we will help you.
We prescribe the very latest weight loss injections (known as GLP-1). Prescriptions are based on individual assessment to determine the best treatment.
When you stop taking the injection, the results can be reversed meaning you have to start your weight loss journey again. However, it’s not dangerous to stop taking the medication and start again if you notice that you begin to gain weight.
Once a healthy weight is reached, some people, who have achieved an energy balance through lifestyle changes (including diet and exercise), may be able to stop taking the medication in certain cases. Yazen offers a loyalty pricing plan for those who choose to commit long term.
Weight loss injections are recommended for people with a BMI of 30+ or 27+ with certain pre existing medical conditions including high blood pressure, elevated blood lipids, elevated blood sugar, atherosclerosis and sleep apnea syndrome.
The medications can also be used to maintain weight loss achieved through dieting or weight loss surgery.
Because it is the body's own hormone that is used, which has only been modified to slow down its breakdown, the side effects are few and mild. In the larger studies that have been conducted, the side effects are relatively similar between test groups taking placebo and test groups taking medicine. Side effects are most common at the beginning of treatment, which is why the initial dose is low and increased slowly.
You may experience nausea, gas, and diarrhoea, mild gastritis, or constipation, but with the support of a dietitian, most symptoms can usually be avoided.
