Why my little guy is so chubby apparently ? I rarely pump but little guy is taking a 3+ hour morning…

Why my little guy is so chubby apparently ? I rarely pump but little guy is taking a 3+ hour morning nap so thought why not. 5 ounces in under 5 minutes and I only pumped one side. Four more days until I've been exclusively breastfeeding for 4 months (1/3 of the way to my goal of one year- not too shabby!) ???