This applies to almost any snake, and really, almost any animal. We might as well include humans too. Too much food for almost anything leads to inactivity and a shortened life span.
It is stated, restated and proven by some of the most knowledgable and experienced boa constrictor keepers around. Russo, Rentfro, Bassett, and there are more that boa constrictors recognize and need some seasonality during the year.
There are times of famine and times of feast.
Certainly don't starve your boa, which is very difficult, but definitely don't overfeed it.
I always see increased activity when the weather warms, the natural dew points increase and there are longer hours of daylight.