So I've found the quick way to do it and I'll add it for reference, but it's simplify calling "area" with the x and y data, much easier than patch or other methods:
fitresult = fit( xData, yData, ft, opts );
xFit = logspace(4,8,1000);
yFit = fitresult(xFit);
yPredict = predint(fitresult,xFit,0.683,'functional','off');
% Plot fit with data.
hold on
h = loglog(sample69_nv20_binw,sample69_nv20_bins,'rd',sample69_nv20_binw,sample69_nv20_bins,'r.',xFit,yFit,'r');
area(xFit,yPredict,'EdgeColor','none','FaceColor',[1 0.3 0.3]);
alpha(0.1);