Today, 06:56 PM
No. Not only is this not possible, even if your baby was only getting foremilk, there is nothing 'bad' about it. All breastmilk contains everything a baby needs.
It sounds like the fussiness is resolving and your baby is ok otherwise-normal gain I assume? In that case, I doubt there is any need to worry about poop color or look. There are many varieties of normal for infant poop.
IF this is an issue of "too much" foremilk, reducing production is one way to go, but as pp suggests it has it's dangers. And in any case, while this does tend to happen when a mom has abundant production, the issue is not really "too much" milk. It is a "too fast" flow. Does baby show any symptoms that you have a fast flow while he is nursing? (coughing, gagging, choking, upset and pulling off the breast, major spitups right after nursing?
If so, A too fast flow is helped by allowing/encouraging baby to nurse very frequently. Assuming normal weight gain, no need for baby to switch sides during a feeding, unless baby wants to. Nursing one side at a time is often helpful in these situations. But having baby stay on the same side for 2 or more sessions is risky as this practice will continue to decrease your milk production. Nursing in a leaning back position, with baby more or less "on top" of you, may also help.
If you wish to revisit the idea that allergies might or might not be a concern, let us know how you did the elimination diet.