The short explanation
Yes, she should see a doctor soon. Rapid weight loss together with constant thirst and tiredness in a young adult can be signs of high blood sugar, including type 1 diabetes, which can come on quickly at this age. Other possible causes include an overactive thyroid, infections, stress, or an eating disorder. A simple blood sugar test can quickly check for diabetes. If her sugar is high, early treatment is important, because untreated type 1 diabetes can lead to a dangerous condition called diabetic ketoacidosis. Please do not wait for her next holiday visit if she is unwell.
What depends on your situation
The parts of this that change from woman to woman. Uncertainty is stated, not hidden.
- Ask whether she is also passing urine often, especially at night, has blurred vision, or feels unusually weak.
- Hostel life, exams and irregular meals can affect weight, but these symptoms together need checking.
- If she is worried about her weight or body image, approach the topic gently and without blame.
What this answer cannot determine
The boundary of online education. These need a clinician who can see you.
- This cannot tell you why your daughter is losing weight. She needs a doctor's assessment and blood tests.
Questions for your clinician
Take these with you. You can add any of them to an appointment card.
- Can her blood sugar be checked today?
- Should her thyroid be tested too?
- Could stress or eating habits be involved?
- What follow-up does she need?
When to seek help
Clinician-approved guidance for this topic. When in doubt, being seen is never the wrong choice.
Emergency — call 112 now
- Call 112 if she becomes very drowsy, confused, has deep fast breathing, persistent vomiting or severe stomach pain.
Get help the same day
- Get her seen the same day for a sugar test if she is very thirsty, tired and losing weight.
Sources
The evidence this explanation is built on.
- Weight loss — unintentional MedlinePlus (US National Library of Medicine)
- Unintentional weight loss NHS
- Type 2 diabetes — symptoms NHS
Who wrote and reviewed this
Every AskHer answer names its author. A clinically reviewed answer also names the clinician who signed it off — if no clinician is named below, it has not been clinically reviewed.
- Author
- AskHer Editorial (AI-assisted draft) AskHer's editorial team — not an individual clinician Works in English, தமிழ், हिन्दी
- Clinical reviewer
- Nobody yet No clinician has signed this answer off, and no person on the editorial team has read it yet. That is what the “Written with AI assistance” label means. It is queued for an editor to read, and then for a clinician who works in this area. The sources it was drafted against are listed above.
- Review status
- Written with AI assistance — not yet reviewed by a person
- Last reviewed
- Not yet reviewed by a person
- Version
- 1
Correction history
Substantive changes are listed, not quietly edited away.
No corrections have been made since this answer was first published.
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