I've been taking Lantus for the last 10 years w/Humalog. I eat whenever I want, and do not follow a specific eating regimen (my day to day life varies a lot). When I was in organized sports with practices/games everyday, I would lower my Lantus. If you know you are going to be doing intense exercise (exercise more vigorous and longer than an hour) the next day, then I would lower your Lantus just a tad, and maybe take a little bit more Novolog bolus during the day. Your Endo should be able to help you finesse the amount of Insulin you should take for your day to day life verses days of intense exercise. If you just started Lantus, you might also have to do some tweaking to get it so you aren't too high or low during the day.