Thanks, Amy.
You made me curious about "Greek" yoghurt-
"Greek yoghurt is made by fermenting milk with live bacteria cultures. ... Greek-style yoghurt, on the other hand, has not been strained and often contains artificial thickeners such as gelatin and gum which are added to produce the same creamy texture, but with a longer shelf life. " and
The difference between natural yoghurt & Greek yoghurt
"Greek yoghurt is higher in fat than standard plain or natural yogurt and is considerably thicker. It generally has around 8 to 10 per cent fat compared to 4 per cent for normal plain yoghurt. ... You get a consistency similar to sour cream or mascarpone while retaining yoghurt's distinctive sour taste".
I think the answer is fat. I know I much prefer the full-fat Greek yoghurt, so, will keep just adding a dollop here & there & maybe have some low-fat fruit added yoghurt for when I really feel like just having yoghurt & fruit.
Time to get moving!