My DS is 7.5 m.o. and we've been doing BLW since 6 months. He started eating right from the word go and eats anything & everything.
The last few days he has had terrible wind half way through every meal. He goes red in the face with effort & straining before passing lots of wind, and occasionally some poo as well. I don't know if this is to do with the food pushing the gas out, or whether it's the position he's sitting in (we have the Antilop high chair).
He's been pooing a lot and sometimes seems to be straining / red in the face, although not as much as when he's passing wind. His poo has been firm and 'formed' rather than squishy. Today he did 5 poos! 
Does this suggest he's constipated? I can't think what could be the culprit. He's had banana, but no more than previously. He's had lots of stone fruit lately - mango, apricot, peach, greengage, but I'd have thought these would have reduced constipation? 
He's probably eaten a fair amount of cheese in the last few days: might that have caused it?
Before this started he had a couple of much wetter than usual poos, including some bran-like bits which I attributed to the mini wheats he had for breakfast a few days running.
He is bf on demand (approx 6 times per 24 hours) and I give him a sip or two of water with meals. I try to give him a stomach massage at bedtime.
Any tips? Seeing him straining is pretty unpleasant to watch!