I walked several caminos in a row. Lost no weight. I think where this may aid weight loss is walking every day in preparation will make walking a habit. Or walking a longer Camino length of time (2 weeks or more) everyday may make it a habit. Walking for a few days is unlikely to make daily exercise a habit.
Also, just noticing that you asked about weight loss walking Sarria to Santiago. That doesn't take longer than a week, so you cannot safely lose much. However, it could be a great part of a longer program.
I lost 20 pounds when I walked from SJPP to Santiago in 2015. It gave me an idea for a new diet...walk 500 miles over 35 days, eat and drink whatever you want, and lose 20 pounds.
I was in decent shape when I left, Once I arrived in SJPP, I eat whatever I wanted, had wine on a daily basis, and beer several times a week. Did not go with any intention of losing weight, however I lost 25 lbs. I think I need to go back.
Go Cougs! I too lost 22 lbs. walking from Pamplona to Santiago but I did imbibe in a little bit of wine....well by Cougar standards.I lost 28 pounds from SJPdP to Santiago. I started out with food poisoning I contracted in Bayonne (my fault) which curtailed my appetite. I had little desire to eat much of anything along the way, but knew I had to. I also could not drink so much as an entire beer. Me—a WSU Cougar! My constant companion was fear of failure. Not until I had my Compostela firmly in hand did I relax completely and partake in the culinary delights of Galicia, including the region's excellent wines. Then came Covid . . .
Too lateI've been eating in bulk to build up a store in case I get lostLose weight between Sarria and Santiago?
Do you know how many places there are to eat between Sarria and Santiago?
I have never lost any weight whatsoever walking a Camino of any distance
Well maybe a couple of pounds after walking 500 miles!
I'd suggest losing it before you go
Too lateI've been eating in bulk to build up a store in case I get lost