If you focus on the diet, you will most certainly break the diet.

FOCUS on the hiking goal. Do backward planning to determine what training you need to do, how long you have to complete your goal (when you want to do your hike)
The motivation of the goal should guide you into fitness (cardio endurance, muscle strength, flexibility) and good eating habits.

Eating whole (not processed) foods only will naturally provide weight loss because you body was designed to use it.

Eating high frutose corn syrup, partially hydrogenated vegetable oils, sodium nitrates, MSG, etc… well your body doesn’t know what to do with that, so it stores it as fat, due to excess insulin response, or in your arteries, again due to an inbalance of the hormone response.

Think of your hiking goal all day….
just like how you probably thought of your overseas trips constantly in the past…
if the goal is not exciting enough – pick one that is exciting… one that would be an emotional let down if you DNF’d (did not finish)
A goal that you are not sure you could finish, that is a little scary.

What will it take to beat your hubby up that mountain side?
What will be the look on his face when you do?

PLEASE stop thinking of this as a diet.
Stop thinking of this as weight loss.

Think of this as a goal first, which will need a new way of eating and will need fitness in order to finish the goal.

After 6 months to a year of going after and hopefully reaching your goal, you will naturally lose weight and will habitually start eating better.