We go for walks all the time. To mix it up DD either rides her bike, scoots or we do a big walk to the playground. We're lucky and also live near our local shops so we walk rather than drive when we only need a few things. DD loves being outside which makes it easier for us.
Since DD discovered the iPad we also now make sure when the weather is nice it's outside play (or basically anything that isn't tv or iPad) until it starts to get dark/too cold.
ETA - we also try not to have junk in the house (just as much for my benefit too haha). We have treats, but we go out for them... Ice cream dates, meals out etc. at home it's just healthy, basic food. Lots of fruit for snacks etc