Why am I gaining weight without eating more?
Last updated September 3, 2026.
Usually aging metabolism, less movement, poor sleep, or a medication - but weight gain with fatigue, cold intolerance, and constipation deserves a thyroid blood test.
What to do
- Track the pace - a couple pounds a year is common; rapid gain is not.
- Review your medications - antidepressants, steroids, and beta blockers are frequent drivers.
- Ask for a thyroid test - one blood test rules the classic cause in or out.
- Note fast gain with swollen ankles - that is fluid, and it needs prompt evaluation.
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