Gaining in one spot - the belly

So I've been trying to up my calories lately and I've gained a pound so far.  Problem is, nothing seems to have changed except my belly, which has grown a lot bigger.  Is this supposed to happen?  My fiber and fat percentage intake is about the same, and I drink the same amount of water, so I have no idea what's wrong.  Any ideas?

its normal to gain weight in your belly first,
it will distribute over time.

ur fibre % is the same but quantity is higher than usually, perfectly normal, if your underweight;once it's proper fat it'll distribute. if you increase intake most ppl find water clings to you (water weight) which subsides over time. drink more water with your more food, maybe descrease salt if you have heaps and more water doesnt help

In weight gain on underweight frames, the weight distributes to the abdomen first. It will then even out. I used to be all weight around the abdomen and am now seeing distribution and look even again. So don't fret and keep going, it does smooth out.