Buy eco shopping bags and then include perhaps:
Recipes of yours for easy, healthy meals (familiar foods stand more chance of being prepared)
Cookbook
Membership to local food co-op
seasonal produce subscription
A few healthy staples or treats. What about dried nori seaweed or some organic chocolates?
Cute fridge magnets
Gift card to someplace they can only buy healthy food
I got this idea from greendeals.org Image is from Eco Bags