Why Pickles Have Fewer Calories Than Cucumbers
Pickle vs cucumber calorie difference is mostly serving size (5 cal per spear vs 45 per whole cucumber). Pickling doesn't dramatically change calories — it mainly adds sodium from brine.
Pickles appear to have dramatically fewer calories than cucumbers (5 vs 40), but this is mostly a serving size illusion. A medium cucumber (~300g) has about 45 calories. The "5 calorie" pickle figure is for a single spear or small serving (~28g). What actually happens during pickling: cucumbers soak in brine (vinegar, water, salt, spices). This slightly changes the water content and concentrates some nutrients per weight, but doesn't fundamentally alter the calorie content. Gram for gram, pickles and cucumbers have roughly similar calories — pickles may be marginally lower due to water displacement from the brine. The real difference is sodium — pickles gain significant salt content from the brine that cucumbers don't have.