We are thinking of going to Italy for our 20th anniversary next summer. Coming from Canada, there will be a 6 hour time difference so jet lag will definitely be an issue. The other problem is that we will only have 5 nights, 6 maximum. Is this feasible? Any suggestions for an itinerary? Not so much into museums, looking more for hiking/scenery and cuisine. Happy to either stay in one place and go on day trips or stay in more than one city/village.

Perhaps the Dolomites? Base in Castelrotto to explore Alpe di Siusi and other areas in the Dolomites. Venice would be closer, but you might find better air connections to Milan.

We had a similar wish to our itinerary (more hiking/scenery) and loved the cinque terre region on the italian riviera. It was a bit more crowded than we originally hoped (went in September) but gorgeous views and a very doable hike between towns. There were also more moderate hiking options available. Venice is also free from a lot of museums if you wanted a larger city but 6 hours of train rides to go between the two (which we did also).

For such a smal trip I take 'melatonin' pills.
It does help (for me)
See your doc - I took them on mine's recommendation.
Enjoy your trip.

Did you look into Sicily ?

I'd chose one base, the easy to get to places include Tuscany, Dolimites, CT, etc. The actual month is important as the level of crowds gets bad at the end of july and start of august. Yoiu may thing this is a minor issue but, for instance there are some walks in the Dolimites (along old WW1 pathways) where my friend had to queue to get up ladders a couple of years back.

Have you thought about cycling as well as hiking?

If I were coming from Canada, I wouldn't pick the Alps for hiking but instead would choose the Amafli coast or the Italian Riviera. (I wouldn't pick the Alps for food. Others like it.) Italian Riviera is a bit easier and quicker to get to, and particularly nice if you prefer green pesto to tomato sauce, Pick someplace less crowded than le Cinque Terre with good scenic hiking, like Rapallo or Camogli. However, if you want pizza and pastry and lots of funny shaped pasta, pick the Amalfi coast.