Crosstraining while doing Stronglifts

Hey everyone,

Looking at getting going on the standard 5x5 beginners program here shortly. I am primarily lifting for weight loss, but with the goal of building a base strength that I can keep building on when I begin to reach my weight loss goals. I know that Medhi talks alot about rest days - I plan to lift in the evenings, and in the mornings swim. 5 days a week on the swimming, Stronglifts only 3 of those 5. I also plan to do light walking and whatnot during my lunch breaks as some added cardio "get out of my chair" time.

Will the extra swimming/cardio bonk me out on lifts? Anyone crosstrained with Stronglifts, or have you made it your only focus during the time you do it?

Thanks,
Ben