Low-Carb only has a couple of fewer calories than regular beer per can.
That's because Carbohydrates aren't as caloric dense as alcohol.
1 gram of alcohol has 7 calories, 1 gram of carbs has 4.
Some brands of Low-Carb beer have both: Less carbs and less alcohol content, making the beer significantly less caloric but also weaker. Because the beer is weaker, people drink more to get drunk, negating the effect of the reduced calories in the first place.
I like beer because I find it refreshing and delicious. I don't drink it to get drunk. If you're also like that and you want to watch out for your calories, my tip is to do it like the Germans.
Take a glass, fill it half with light beer and half with lemon juice and soda water, or half light beer and half zero sugar sprite/coke.
It is delicious, refreshing, and it cuts the bitter taste some people hate in beer. It also increases volume, so you're going to be "satiated" faster