NHS Factsheet

NHS website

Unintentional weight loss

Find out what can cause unintentional weight loss and when to get medical help.

23 December 2022

Introduction

Unintentional weight loss is when you lose weight without changing your diet or exercise routine. It can be a sign of stress or a serious illness. See a GP just in case.

Causes of unintentional weight loss

Unintentional weight loss has many different causes.

It might be caused by a stressful event like a divorce, losing a job, or the death of a loved one. It can also be caused by malnutrition, a health condition or a combination of things.

Some causes of unintentional weight loss include:

Sometimes weight loss can be caused by cancer. It's important to get it checked if you're losing weight without trying.

See a GP if:

  • you keep losing weight without changing your diet or exercise routine

Treatment for unintentional weight loss

Treatment for unintentional weight loss depends on what's causing it.

A GP will ask about your health and may arrange some tests or scans.

Depending on the possible cause, they may:

  • advise you about things you can do to help, such as ways to reduce stress
  • recommend treatment for any condition that's causing you to lose weight
  • refer you to a specialist