Got it — here are a few clean variations, depending on the vibe you want:
Simple & natural
- One spoonful every night for three days helped flatten my belly.
Smoother flow
- One spoonful each night for three days helped flatten my belly.
Softer / less absolute
- One spoonful every night for three days really helped reduce my belly.
More curiosity-driven
- One spoonful every night for three days—and my belly looked noticeably flatter.
If you want it more casual, more dramatic, or safer-sounding (less “promise”), say the word and I’ll tune it.