Hiking season is in full swing, and each weekend, thousands of adventurers are flocking to New Hampshire’s peaks and trails to experience the satisfaction of joining the 4,000-footer club or simply communing with nature on an easy trail through the woods.

Whatever outdoor adventure you’re planning, though, be sure to bring enough fuel to get you up and down the mountain. And in this case, the fuel isn’t pumped out at the local gas station.

“I personally do trail mix,” says Garrett McGurn, of Bedford, who works at the Nashua branch of Eastern Mountain Sports. “If you just eat candy, you’ll crash. You want to get some carbs for that energy boost, but you also want long-lasting endurance.”

McGurn mixes dried fruit, nuts and cereal for the right boost of carbohydrates and protein. He says high-calorie snacks with the proper nutrients can keep the body going, and the work of hiking will help burn it off.

“Hiking is really not the time to be counting calories,” he says.

Marianne O’Connor, of Nashua, agrees, but adds that portability is an important quality to keep in mind when packing a hiking snack. The mother of two and author of “Haunted Hikes of New Hampshire” says she has learned the hard way what is appropriate to bring and what is better left at home, in the kitchen.

O’Connor formerly worked with Positive Environmental Adventures for Kids, or PEAK, with the Nashua Youth Council, taking inner-city kids hiking for the first time.

“If you pack a candy bar – forget it. On a hot day, by the time you’re ready to eat, it’s just fudgy soup,” she says and laughs at the memory of less-than-stellar hiking snacks. “You find out what works, what’s sturdy. You really do need food that is going to hold up in an unpredictable environment, with things bumping around in your pack.”

O’Connor seconded the portability of trail mix.

“You would be so surprised how good Cheerios taste with chocolate chips, nuts, granola and sunflower seeds,” she says.

O’Connor also recommends sturdy fruit, such as an apple or Clementine.

“If you can keep them cool, individually wrapped cheese sticks are a great source of protein,” she says. “Just remember to carry out the trash.”

Mary Ellen Hettinger, of Amherst, the public relations manager for the Girl Scouts of Swift Water Council in Bedford, says getting young children involved in planning the snacks for a hike can be half the fun.

“You can talk about what’s going to melt or if you’re going to have to worry about something needing freezing,” she says. “It gets them started talking about simple nutrition and what’s a healthy snack.”

Hettinger says that type of discussion, particularly when it involves a large group of young hikers, can help determine whether someone has an allergy or other dietary concern. It also breeds ingenuity.

“If you go hiking for the day, you might want to freeze juice boxes in the morning,” Hettinger says. “Then you can use the juice boxes as a cold pack for something like hard-boiled eggs, which are an excellent source of protein.”

McGurn says packed snacks can often be supplemented by treats found along the trail, such as wild blueberries.

“They’re pretty recognizable,” he says. He says they grow on rocks in the sun and are in prickly bushes, and they are much smaller than the blueberries you find in the supermarket. But, McGurn advises, never eat a berry or plant unless you’re absolutely certain you know what you’re ingesting.

“It’s not worth the risk of being unsure.”

McGurn suggests stopping for a nibble every 20 minutes or so, or for a boost when hikers are feeling fatigued. “I keep trail mix in my pocket and nibble for the whole hike,” he says.

He also recommends hikers stay well-hydrated.

“Gatorade and Powerade contain electrolytes, which you lose when you sweat,” he says. “You may not notice it, but your body will operate more efficiently if you’re replacing them.”

For O’Connor, nothing beats good old-fashioned water. “I am constantly sipping water while I am hiking. I think a good rule of thumb is that you should have about two quarts of water and an extra supply just in case,” she says.

She recommends also packing a whistle, first aid kit, jacket, mittens and even a little cash.

“You can never be overly prepared.”

“Haunted Hikes of New Hampshire” is available at Barnes & Noble in Manchester and Nashua, online at Amazon.com and at Toadstool Bookshop in Milford.