The key to these mini snacks is to keep feeding yourself a continuous, light stream of easy-to-digest, carb-focused calories at regular intervals. Think somewhere in the 75 to 150 calorie range. If you’ll be running for several hours, it might be smart to start mixing in some fat and protein, too. (Ultrarunners have been known to pack pizza slices, potato chips, and even cake frosting for fuel on the go.) But for the first couple hours, foods like gummy chews or gels work great. Some other good options include bananas, cooked potatoes, date and coconut balls, rice balls, and peanut butter and jelly. Just make sure to pay attention to how much fiber you’re ingesting, since too much can cause digestive distress.
One additional thing to think about: electrolytes. Again, a good rule of thumb is that if you’re running longer than an hour, you’ll be sweating out enough electrolytes (crucial minerals like sodium, potassium, calcium, and magnesium) that you’ll need to replace them as you go. Some sport chews and gels include electrolytes in their recipe, and so do many sports drinks. So as you’re fueling yourself through the run, make sure to pay attention to electrolytes as well.
After the run
Congratulations, you made it through your long trail run! Now it’s time to catch up on calories and hydration. Think water, protein, and maybe electrolytes, too. One reason to carry plenty of water on your run is that it can take a while to catch up on hydration once you get dehydrated. The average person can only absorb about a liter of water an hour, so even if you come home and slam multiple liters, it won’t do you much good if you let yourself dip too far into the dehydration zone. If you do feel dehydrated when you’re done, sipping water continually for multiple hours can help you catch up.
You can typically replace missing electrolytes by eating regular foods. Many sport drinks and mixes offer specifically balanced amounts of sodium, calcium, potassium, and magnesium, but sodium is still by far the highest ingredient, and salty snacks like chips and nuts have plenty of it. And finally, for repairing muscle tissue you broke down during your run, focus on protein, like eggs, beans, veggies, fish, and lean meats.