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What is a healthy weight for adults?

profile picture of Christina Merryfield
Senior Specialist Dietitian, Cromwell Hospital
21 November 2023
Next review due November 2026

Keeping to a healthy weight can help you to reduce your risk of several health conditions. But what exactly is a healthy weight for adults? Here, I’ll explain how to work out whether you’re a healthy weight and what changes you can make if you’re not.

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How does weight affect your health?

If you’re overweight or obese, it can increase your risk of developing a wide range of health problems. These include conditions such as:

You may also be more likely to have trouble with symptoms like breathlessness and low back pain.

But, being underweight is not risk-free either. If you’re underweight, you may not be getting enough of the right nutrients in your diet. This can also increase your risk of certain health problems, such as:

  • reduced muscle strength
  • increased risk of illness or infection
  • increased risk of heart problems
  • fertility issues
  • slower wound healing

Keeping to a healthy weight may help to reduce your chance of developing these health problems.

How to find out your ideal weight?

The ideal weight for you will depend on your height and other factors, such as whether you have a lot of muscle. The most simple way of measuring if you’re a healthy weight for your height is to calculate your body mass index (BMI).

Your BMI can tell you if you’re underweight, a healthy weight, or overweight. You can use our calculator to work out your BMI.

Just be aware that BMI isn’t a useful measurement tool for children, the over 65’s, or very muscly people.

It’s also useful to look at your waist circumference and how this compares to your height (your waist-to-height ratio). This gives a better idea of where you store fat on your body. This is useful because having extra weight around your tummy (abdomen) is more risky than storing it around your hips and thighs.

To measure your waist circumference, wrap a tape measure around your middle when standing. You should place the tape halfway between the top of your hips and the bottom of your ribs. Generally, this is just above the belly button. Breathe out before measuring your waist.

Calculating waist-to-height ratio

Measure your height using the same units you measured your waist circumference in, (either centimetres or inches). To work out your waist-to-height ratio, divide your waist measurement by your height measurement. Use a calculator or your phone to do this (waist ÷ height = ratio). The answer should be a decimal number.

Here is how waist-to-height ratio affects your health risks.

  • 0.4 to 0.49 = healthy amount of fat around your middle, no increased health risks
  • 0.5 to 0.59 = increased fat around your middle, increased health risks
  • 0.6 or more = high amount of fat around your middle, further increased health risks

A good way to think of it is that you should try to keep your waist measurement to half your height (this gives you a waist-to-height ratio below 0.5).

These categories are for people with a BMI under 35kg/m2, and are the same no matter your sex and ethnicity. They also apply to people with high muscle mass.

Reasons for weight gain or loss

Changes to your weight are mainly down to the balance between calories you take in through food and drink, and calories you use in activity. Put simply, you'll:

  • gain weight, if you take in more calories than you use up
  • lose weight, if you use up more calories than you take in
  • maintain your weight, if you balance the calories you take in with the calories you use up

Other factors can also make a difference. For instance, your genetic make-up can sometimes make you more likely to put weight on.

Other things that can affect your weight include the following.

Getting older. As you get older, you lose muscle mass and gain body fat instead. Your metabolism also slows down and you have lower energy requirements. This makes it easier to put on weight.

Menopause. Weight gain during menopause may be partly due to falling levels of the hormone oestrogen in your body. This is in addition to the changes that happen to your body as you get older, described above.

Malnutrition in old age. Although weight gain is common as you age, people in the oldest age groups (above 75) are also at risk of becoming underweight. This may be due to difficulty eating, cooking, and preparing food. Older people may also be more likely to have a poor appetite and to have health conditions.

Medicines. Certain medicines, including steroids, some types of contraceptives, and some antidepressants can cause an increase in weight. Other medicines may reduce your appetite, change your taste or affect your digestive system, leading to weight loss.

Medical conditions. Conditions that affect hormone levels, such as polycystic ovary syndrome and underactive thyroid can cause weight gain. Meanwhile, living with a long-term health condition like diabetes or kidney disease can be associated with weight loss. Digestive problems, depression and cancer can also cause weight loss.

Reaching a healthy weight

If you're currently over or underweight, making some changes to get to your ideal weight will really benefit your health.

If you’re overweight or obese

If you’re overweight, aim to reach a healthy BMI and waist-to-height ratio by losing weight gradually. A good target to aim for is losing about 0.5 to 1kg (1 to 2lb) a week.

To lose weight, you'll need to use up more calories than you take in from food and drink. Reducing your calorie intake and increasing how much activity you do can both help.

It's worth thinking about the following points.

  • What you eat. Eating foods high in fat and sugar will make you more likely to put on weight.
  • How much you eat. Many people eat much larger portion sizes than they need.
  • How you eat. Eating quickly or when you’re doing other things, like watching TV, can result in overeating. Try to eat slowly, focusing on your food.
  • How much alcohol you drink. Alcohol is high in calories and can contribute to weight gain.
  • How much activity you do. Looking for ways to be more active can help you to lose weight and keep it off.

If you’re underweight

Being underweight means you might not be getting all the nutrients, vitamins, and minerals that your body needs to be healthy.

To put on weight, you will need to try to increase your calorie intake by eating a balanced and nutritious diet.

Healthy ideas to boost your calorie intake and increase your weight include the following.

  • Try to eat little and often. Aim to have nutritious snacks in between meals, like cheese and crackers, creamy yoghurt, flapjacks, nuts, and seeds.
  • Avoid low fat and diet versions of foods and drinks. Go for higher fat options of milk, cheese, cream and other foods, until you reach your ideal weight.
  • Foods that are high in protein can help to build you up. These include meat, fish, eggs, nuts, beans, pulses, and meat-free protein alternatives.
  • Add cheese to sauces, potatoes and vegetables, and add milk powder to mashed potato, puddings and soups to increase energy and protein.
  • Have milky drinks, like hot chocolate, malted drinks, smoothies, and milkshakes.
  • Have some ready meals and other foods that are easy to snack on for times when you don’t feel up to preparing food.

If you have a health condition, talk to your doctor or a dietitian first before making any changes to your diet.


The Bupa weight management plan is designed for people with a BMI over 30 (or over 27 if you have a weight related condition). The plan is designed to empower you to achieve and maintain a healthy weight in a sustainable way.
Discover more about our medicated weight loss plan.

profile picture of Christina Merryfield
Christina Merryfield
Senior Specialist Dietitian, Cromwell Hospital

 

Co-author

Julia Ebbens, Health Content Editor at Bupa UK

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Co-author

Julia Ebbens, Health Content Editor at Bupa UK

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