diff --git a/backend/routers/nutrition.py b/backend/routers/nutrition.py
index 3c6d46a..223dacc 100644
--- a/backend/routers/nutrition.py
+++ b/backend/routers/nutrition.py
@@ -153,7 +153,9 @@ def nutrition_weekly(weeks: int=16, x_profile_id: Optional[str]=Header(default=N
     if not rows: return []
     wm={}
     for d in rows:
-        wk=datetime.strptime(d['date'],'%Y-%m-%d').strftime('%Y-W%V')
+        # Handle both datetime.date objects (from DB) and strings
+        date_obj = d['date'] if hasattr(d['date'], 'strftime') else datetime.strptime(d['date'],'%Y-%m-%d')
+        wk = date_obj.strftime('%Y-W%V')
         wm.setdefault(wk,[]).append(d)
     result=[]
     for wk in sorted(wm):