Frankly for most hikers this kind of thing isn't a huge issue. It only becomes something to think out if you go past 3 weeks or so out. For the typical hiker you could eat Ho-Ho's all weekend and exist. My point being is that until you burn off all your excess fat and your body becomes tuned to day in/day out hiking (as with thru hiking) you have little to worry about. What happens with thru's is they burn off the fat but then cannot add in enough food for what their body is burning. At that point yes, they can start eating away at muscle. But just eating protein won't preserve it. Eating muscle doesn't give muscle back. Rather one needs a balanced diet with carbs and protein for the body to work. And lets face it: long distance hiking is not the way one builds bulky muscle!

As long as your belly is full, you are getting a semi-balanced diet and have energy - then don't worry. If a person eats well at home they have little to worry about when hiking for a day, a weekend or a couple weeks.

PS: And consider this - take a look at what many thru hikers eat for a diet. It is often binging in towns, then eating a steady diet of what many would consider less-than-good picks of food. These diets of Snicker bars, Pop Tarts, Ramen, Lipton noodles and jerky have fueled many a hiker thopusands of miles. It is easy to digest.

And that is a simple thing to think over - a diet high in animal based protein is very hard to digest. It takes longer, leaving one sluggish while the food works it way through. Carbs are easy to get through, fueling you up quickly. Wheat based carbs contain protein as well........