Hilary Duff's Bae is Packing Heat!!

Hilary Duff sure knows how to bag 'em ... just get a load of her swollen BF.

Hilary and her celebrity trainer BF, Jason Walsh, were on their way out Thursday at LAX. Our photog does his best to grill the hot couple but we'll forgive you if your eyes are fixed on his ripped bod.

Notice he's carrying ALL the bags.

#HotDamn