Most nutrition tools are reactive
Most meal apps work after the fact. They collect data after eating, summarize what happened, and ask users to do better next time. That can help, but it depends heavily on memory and motivation.
Guidance before the meal is different
Guidance before the meal tries to shape the decision before it happens. That is where clearer portion expectations, more confidence, and less friction can make the biggest difference.
Why this matters for PortionPro
PortionPro is built around that idea. The product is meant to help people see a more appropriate amount before they start eating, not just review the outcome later.