If you want to work out whether you’re a healthy weight, the BMI chart might be able to offer a helping hand
What is BMI?
In short, Body Mass Index (BMI) is a measurement that uses your weight and height to calculate and produce a BMI score. This score helps indicate whether you are a healthy weight. Age and gender are also two factors taken into consideration when calculating the BMI score of children and young people aged two to 18.
Your BMI can tell you if you’re carrying too much weight. However, it can’t tell the difference between excess fat, muscle or bone, which we’ll go into later. For most adults, their BMI score can give them an indication of their health risk, although it’s not necessarily suitable for everyone.
How do you work out your BMI score?
To work out your BMI, divide your weight in kilograms (kg) by your height in metres (m) squared. You can use a free BMI calculator online to help you work out your score. Alternatively, you can use a BMI chart.
Once you’ve calculated your BMI, you can work out which category your score belongs to:
• Below 18.5kg/m2 – you're in the underweight range
• Between 18.5kg/m2 and 24.9kg/m2 – you're in the healthy weight range
• Between 25kg/m2 and 29.9kg/m2 – you're in the overweight range
• 30kg/m2 or over – you're in the obese range
What is a normal BMI?
There isn’t a specific score that would class as a ‘normal BMI’. The same as there is no normal weight class to belong to or normal height. There are plenty of factors that can affect both our weight and height, such as family history, age, ethnicity and illness which we cannot change.
Your health is unique to you, and everyone is different. BMI doesn’t have to be a defining factor in your health but it can be a useful tool and works better for some people more than others.
Although there’s no ‘normal BMI’, the 18.5 to 24.9 range is noted as an ideal category for adults to fit into. Although this is seen as the ‘healthy range’, someone who falls into this category can still have excess tummy fat.
One way you can measure whether you have excess tummy fat is by calculating your waist to height ratio. You can do this by measuring your waist and dividing it by your height. Those with a waist to height ratio of 0.5 or higher are thought to be at an increased risk of conditions such as type 2 diabetes. If you’re concerned about your waist to heigh ratio, consult with your GP.
What are the limitations of BMI?
Your BMI calculation does not include muscle mass. The limitation here is your muscle mass weighs more than fat. This means athletes and very muscular adults can be categorised into the ‘excess weight’ range even if their body fat is low.
So, what does this mean for adults who lose muscle as they get older? In some instances, they may fall into a healthy weight range even if they are carrying excess fat. There are also a few circumstances where BMI calculation is not suitable, including:
• If you have an eating disorder
• If you are pregnant
• If you are under 18 years old
If you’re concerned about your weight, you can seek further advice from your GP.
How does BMI differ for different ethnic minority groups?
Black, Asian and ethnic minority groups have a higher risk of developing some long-term conditions, such as heart disease and type 2 diabetes. Their exposure to these health risks start to rise at a lower BMI. Therefore, people from these groups who have a BMI of 23 are at an increased risk. Those with a score of 27.5 or more are at a high risk.
If you’re worried about your weight and exposure to health risks, seek advice from your GP.
What else should you take into account for a healthy weight?
Take a look at the following tips to help you work towards and maintain a healthy weight.
Tip 1: Plan regular meals
Not only will this help you remain within your daily calorie allowance, but it also ensures you don’t skip important meals like breakfast – eating essential nutrients in the morning can help you refrain from snacking throughout the day.
Tip 2: Drink plenty of water
Often, we can confuse hunger with thirst. Instead of a snack, your body might be yearning for a glass of H2O. If you struggle to incorporate water into your daily routine, read these practical tips on how to drink more water.
Tip 3: Get active
Whether you’re looking to lose or maintain weight, becoming more active is vital to help you achieve your goals. Don’t make exercise a chore, find an activity that you enjoy and incorporate it into your weekly routine. This can be anything from regular walks to engaging in your favourite sports.
As a guideline, the NHS recommends that adults aged 19-64 should do at least 150 minutes of moderate-intensity physical activity (such as water aerobics) or 75 minutes of vigorous-intensity activity (such as running) every week. If you haven’t engaged in exercise for some time or have a medical condition, speak to your GP.
Tip 4: Understand calories
Although calories aren’t the enemy, it can be easy to consume more of them than our bodies actually need. In these instances, those excess calories store as body fat which can contribute to weight gain. The number of calories you need to maintain a healthy body weight depends on a few factors like your age and size.
As a general guide, the average man needs around 2,500kcal (10,500kJ) a day to maintain a healthy body weight. For the average woman, it’s around 2,000kcal (8,400kJ) a day.
Tip 5: Prioritise portion control
Portion control can assist you in making healthier life choices and ensure you that you’re eating the right foods. One top tip that can help you with this is using a smaller plate for your meals. It’s a great way to slowly minimise your portions without the burden of going hungry.
Tip 6: Get your five-a-day
As the old saying goes ‘five-a-days keeps the doctor away’. Although that’s not a guarantee, consuming five portions of a variety of fruits and vegetables each day can contribute to a healthy, balanced diet. Fruit and veg are low in calories and fat and many have the added bonus of being high in fibre – it’s a recipe for success when it comes to maintaining a healthy weight.
Find out more information about how you can achieve these steps by reading our how to lose weight guide.
Who can help you if you’re struggling to lose weight?
Losing weight can be challenging so try not to feel disheartened if you’re struggling. There are plenty of resources out there that can help, such as your GP or nurse.
If you would prefer to not talk in person, there are also plenty of online resources like the NHS Better Health website and our very own Weight Management Health Hub which each offer free tools and advice to support effective weight management – all from the comfort of your own home.
You can also seek online support and advice via the Boots Online Doctor Weight Loss Treatment service.* After filling out a quick online consultation (that should take no longer than 10-15 minutes), one of our clinicians will assess you and prescribe treatment if appropriate. They can also offer advice if you’re struggling to maintain a healthy weight. Alternatively, you can speak to your pharmacy team or GP for further advice.
*Access to prescription-only treatment is subject to an online consultation with a clinician to assess suitability. Subject to availability. Charges apply.
