Visual to show a graph with ranges

Thanks for the suggestions, everyone. I will try them both, but I cannot believe that a visualisation package as sophisticated as Power BI, with all the weight and influence of Microsoft behind it, does not already have a visual (or a third party one) that caters for this pretty basic aspect of displaying information in graph form???

Just to add a bit more context to this. The points plotted on the graph are the weights, as indicated on the left hand Y axis. The right hand Y axis is linked to the BMI of that person, based on their weight and pre-determined height. It's therefore not entirely possible to put some constant Y axis lines in, because BMIs depend on your height and weight (plus other things, but for simplicity let's leave it there). 

Hi, not sure about the shading but if you add your values weight or BMI to a line chart, you can then add a constant line that defines the threshold between "Normal" and "Overweight". This can be done by creating a measure e.g. "Overweight Threshold = 25" and adding the measure to your line values, or clicking on "Analytics" (the magnifying glass symbol) in the Visualizations pane and creating a "Y-Axis Constant Line.

To create the shading maybe you would need to add a fixed axis to your graph (add a "Minimum" and "Maximum" value to the Y-axis) and then add a background image containing the shading to the "Plot area background" formatting option in the line chart. Might be tricky but possible.