My contribution too

Two years ago I tackled the stress and excess weight problem. Weight is a combination of proper diet and regular exercise, at least 3x weekly you have to sweat for 40 minutes.
Diet:
- at least 5 meals/day, best at the same times (e.g. 7h,10h,13h,16h,19h depending on schedule).
- abundant varied breakfast with all components (carbs, proteins, fibers)
- snack fruit (one piece, e.g. apple)
- lunch normal varied
- afternoon snack proteins (yogurt, kefir etc)
- dinner proteins and veg
General diet rules:
- no carbs after lunch
- avoid high GI food (white bread, white flour pasta, white flour sweets, potatoes)
- no eating 2h before bed
Such "diet" is not hard, no hunger, but maintains weight only, not lose. For losing need exercise.
For hills per experience need aerobic training for body to hold "oxygen balance" long term. Layman: fitness. Plus muscle strength (mass), usually weights, or exercises (leg squats etc) till muscles burn. After no carbs but steaks! Muscles heal with protein, gain mass/strength. Recommend gym smart; not all for all, what you want (leg power, lose belly, maintain fitness...).
Training e.g. 40min sweat (fast walk Šmarna Gora for Ljubljana folks, though fast you top in 30min or less

).
Hiking itself not for "weight loss" cuz need energy/carbs supplied. Short: no hunger then, but better steak after valley return than schnitzel and fries