Obviously, the solution to this problem is to pack food that everyone enjoys eating. However, according to Murphy, this doesn't always happen. Also, sometimes the best tasting food is ruled out by weight/price/space constraints.
So if you are on a backpacking trip with people who are complaining about and/or refusing to eat the food because of the taste/smell/texture/unfamiliarity, what do you do?
First step is to try to find out what, among what you have, they do like. Maybe they hate freeze dried beef stroganoff but like freeze dried spaghetti and meat balls. To the extent you can without being totally unfair to the rest of the party, give them more of what they like, even if it means you have to eat more beef stroganoff, which you don't like either. They must like the trail mix and the chocolate and the cheese....let them have somewhat more than their share of that, but not all of it.
If a modest effort at accommodation doesn't work, treat them as you would a bratty child -- which is what they are. Tell them:
I know this isn't Cordon Bleu cuisine, but it is what we have. Eat it or starve.
The rest of you have to be united in this approach.
After a few days, maybe step up the pace of the trip. If they get hungry enough, they will eat. Do not, repeat, do not worry about their starving.
It is usually impractical to split up, because the party usually has only one stove and one of some other essentials.
Lastly, never travel with them again.
I've been involved with hiking/trekking clubs around my area here. I was what they call chief guide for a few years (responsible for organizing trips and lead some of them together with other club members).
One of the clubs I used to be involved was an university club and as such we had heaps of exchange students. In all those trips, we always had the culture of cooking together dinner and breakfast. It makes easier to bring one set of pots and one fuel cooker (plus a little gas one for emergency) and split between the party. Because the diversity of people from everywhere I had various occasions that party members had unusual allergies (found people allergic to garlic, ice, tomato and a few other things, intolerance of some sort (milk, gluten, etc) and and the occasional picky one.
Breakfast was fairly easy. A big pot of porridge for the party (usually around 5-6 people). People were advised to bring toppings for the porridge (good old Scots and their salty porridge, others with their brown sugar and cinnamon and so on). People not keen for the porridge would bring their own breakfast.
Similar idea for dinner. We would cook something for everybody. Many time I cooked the mince for the group and some gluten free pasta aside for the gluten free person. I used to send them an email with the plan for the walk and breakfast and dinner. Anyone not happy with either or both were asked to suggest something else or bring their own.
I think the bottom line here is we cannot please everybody. :)
The organized meal is already covered by the other answers, so let's add some ways to avoid the problem altogether:
These solutions are more practical on shorter trips. On a weeklong trip go with the other answers to save weight. Also, if you go with the solutions in this answer be prepared to suffer the smell of 3 day old cheese sandwiches.
Last but not least, you can combine the options:
It seems like you're assuming there will be group meals, but that's totally unnecessary. In fact, group meals tend to lead to health problems, because people get diseases like giardiasis from each other by hand-to-mouth transmission, due to primitive hygiene.
A really simple solution, which I've been using for years, is freezer-bag cooking. Each person brings their own dinners, each in a separate ziplock freezer bag. They bring whatever they like. At dinner time, you boil water and give each person the amount that they need to add to their bag. Seal the bag, wait for it to cook.
You can do this with commercial freeze-dried backpacking meals, many supermarket instant foods such as instant couscous, or recipes that you make at home. There are cookbooks for this, such as Lipsmackin' Backpackin' by Conners.
For more information on giardiasis, see Thomas R. Welch and Timothy P. Welch, "Giardiasis as a threat to backpackers in the United States: a survey of state health departments," Wilderness and Environmental Medicine, 6 (1995) 162, Giardiasis as a threat to backpackers in the United States: a survey of state health departments.
When we go backpacking, we first gather to discuss the logistics, and part of that is meals. Each person knows what they like, I write them all down and order them online or head over to the camping section of Target or whatever. So, our meals are usually commercially-prepared individual or two-person portions. It's easy for us then, I just order 3 of this, 6 of that, 1 of the other thing. Sometimes, I'll buy an extra of something new just to try out. But everyone gets what they want, and we never have problems with picky eaters. Occasionally, someone doesn't like this brand or that, or would prefer a different brand offering. If the cost differential isn't that much, we'll absorb it, not a big deal for us. That's the scouting way.
This, of course, works when you are buying commercially prepared individualized meals, which can be more expensive than group meals - which might be what you are referring to. If this is the case, then I recommend to gather before the trip, and vote on a meal. Whoever are the minority votes, they have a choice: eat with the group and pay group rates; or they can separately purchase or prepare their own individual meals.
Everyone must understand that not all people can be satisfied all the time. Those who are difficult eaters must realize that their eating habits cause problems for others, as in cases like this. Therefore, expect some give and take, but the more choosey one is, the more give one will have to provide.
Do be sensitive to allergy, religious, or dietary requirements. What to do when the whole group wants ham and cheese sandwiches, and the one among you is Jewish. Or everyone wants peanut butter and jelly, but one person has allergies to peanuts.
In the end, the Jewish person may have to prepare his own sandwich. And the girl with the allergies... with severe allergy potential, she should be preparing her own foods anyway. And the fight over whether to get sugarfree snacks or sugared snacks? Work that in with a group decision. Compromises like "you'll burn off the sugar on a hike anyway" and "the whole purpose of a sugar snack is for energy, so why remove the energy from the energy snack" will have to come up, and you might decide on something altogether different with neither sugar nor carcinogenic chemical substitutes. ;-)
There will be different approaches depending on how much you are "in charge" of the group. Also, I understand the setting is that the group is already on the trip, possibly with limited possibility to extend or alter food supplies. (If you are just preparing for the trip, then the situation is easier, of course.)
If you are on the trip, and intend to share meals prepared by group members in the open, out of supplies you brought with you, then the situation is quite simple. Make a list of all supplies you have or can get hold of. Then involve the group in menu-making, the fussy eaters in particular. Make your point clear: out of this stuff, what do you suggest we cook for the next few mornings/nights?
In a group of equals (in terms of responsibility for the outcome of the trip), such as a group of friends, I would not go beyond this basic sharing of responsibility. If you are in charge (of a group of kids, or of your clients on a tour), you've assumed responsibility for them, but your situation might be alleviated by a previous contract (of whatever degree of formality) with them or their parents: if you said earlier that such and such food will be served at such and such intervals, then you simply proceed as planned.
If your charges are so picky that they are unable to sustain their strength for the tour, you can try preparing meals that consist of two or more different courses or parts (such as, steamed ham and pea mash). Then you offer each person to partake of either or both, and help themselves to bread as accompaniment. Do not give any "substitutes" to those who do not opt for either of your courses. (Consider occasionally giving a small dessert to those who do, if they are kids.)
Further, if they are kids in your charge, drinks can help in terms of giving some extra kick for the day and also creating team spirit. On a cold morning, hot cocoa or ginger tea with honey can work wonders.
What we did in our local scout troop when we met picky children during several day long hikes:
If any of the children/youngsters has an alternative we are glad to hear it and ready to implement it within our possibilities and money limits.
When camping in the same place in nature for more days we still met some constraints: no opportunity for storing raw meat or eggs for a longer time; if we wanted to cook some meat, someone had to go to the village in the morning and get it. We learned to deal with this by using canned food + spicy, saucy recipes which take the attention away from the can's taste. Also, we introduced days with more "fun" food for the children, such as pancakes or something they like: this is always a pleasant surprise for them. These remain as highlights, so they never mention that one time when they had pea mash (something less popular). When they really choose not to eat, then we give them one alternative: bread with some spread - not chocolate or marmalade, but something average.
At the end of the camp we make a feedback session, and then usually we hear things like "next time don't cook this or that". If there is a general argument against a food, we will take it off the list.
Same worked out on biking trips (2 week long with 35 people). When we had resting days we cooked more interesting foods, which was fun and rewarding too.
