Are you underweight?

If you’re underweight, you could be damaging your health. Weighing too little can contribute to a weakened immune system, fragile bones and a lack of energy.


If you're concerned that you're underweight, check your weight using our Healthy weight calculator.


If diet is the cause of your low weight, changing to a healthy, balanced diet can help you achieve a healthy weight. 

The questions like: 


Why are you underweight?
If our healthy weight calculator has told you that you may be underweight, think about why this might be:


Have you been unwell?
Have you been eating healthily, or have you been skipping breakfast or lunch and just eating snacks on the go?
Have you lost your appetite, perhaps because you’re stressed or worried?
Have you been trying to lose weight? Are you more focused on being 'thin' or looking a certain way than on being a healthy weight?
Are you not eating because it gives you a feeling of control or power?


Talk to someone
There may be emotional issues that are stopping you from eating a healthy diet.
If you feel anxious or worried when you think about food, or feel you may be using control over food to help you cope with stress or low self-esteem, you may have an eating disorder.
If you think you may have an eating disorder, help is available. Find out more about eating disorders.
Why it matters
Being underweight is bad news for your health now and in the future:

• Lack of energy. Being underweight can leave you feeling drained and tired. You may have anemia (a lack of red blood cells) because you’re not consuming enough iron.
• Nutritional deficiencies. If you’re underweight, you may be lacking vital nutrients that your body needs to grow and work properly. Calcium, for example, is important for the maintenance of strong and healthy bones. Being underweight increases the risk of osteoporosis (fragile bone disease) later in life.
• Weakened immune system. Your immune system is not 100% when you’re underweight, making you more likely to catch a cold, the flu or other infections.

For women, interrupted periods and difficulty becoming pregnant in the future. Women who are underweight can find that their periods stop. This increases the risk of future problems with fertility.




Healthy high-energy foods
If you’re trying to gain weight, eat foods that are not only healthy but are also packed with energy. Try the following:

• for breakfast, porridge with chopped fruit or raisins sprinkled on top, or eggs on toast
• fruit smoothies or milkshakes for a great snack (make them at home and take them to work or college)
• for a healthy lunch, a jacket potato with baked beans or tuna on top, which contains energy-giving carbohydrate and protein
• peanut butter on toast for a high-energy snack
• yogurts and milky puddings, such as rice puddings
• nuts, which are high in 'good' unsaturated fats (choose unsalted varieties).