I worked with a capsule-wardrobe stylist to pack sustainably with just a backpack for a 5-day trip to the Great Smoky Mountains. Here's what I brought.

Lately, I've been taking just a backpack with me when I travel.

It started in August 2022 when I spent a week traveling by train from my home in New York City to Niagara Falls and the Canadian cities of Toronto, Montréal, and Québec City. I only had enough time to spend one or two nights at each destination, so traveling with a backpack seemed easier than packing a full suitcase.

The lighter load made me feel more mobile, and I had an easier time keeping track of all my stuff.

Two months later, when I took a two-week train trip through four European countries, I crammed everything into my backpack again. I packed even lighter than I did for my first trip, even though it was twice as long.

Most recently, I was set to take a five-day trip to Great Smoky Mountains National Park in Tennessee, and I wanted to try packing lighter than I ever have before.

Efficiency sparked my interest in backpacking, but learning that packing lightly is also a more sustainable way to travel kept me hooked.

Sustainable travel experts who previously spoke with Insider said that packing as lightly as possible can help the environment, especially when it comes to air travel.

"The more weight an aircraft carries, the more fuel it burns; the lighter the load, the less polluting," Justin Francis, the cofounder and CEO of Responsible Travel, told Insider. "So pack as light as you reasonably can. If you avoid the hassle of checking a bag, that's a bonus."

To put that into perspective, according to FiveThirtyEight, Southwest's fuel costs increase by more than $1 million per year if every passenger carries a cell phone, and $21 million if everyone carries a laptop.

Learning about the impact of weight on a flight's pollution made me want to pack as lightly as possible for my Tennesse trip.

On my previous backpacking trips, I found myself growing bored with the clothes I brought after a few days.

I was wary of feeling this way again, until I learned about capsule wardrobes.

Capsule-wardrobe styling is about selecting a small number of clothing items that are versatile enough to be worn together in different ways and neutral enough to be paired with anything else in the wardrobe, according to Reader's Digest.

The idea of bringing fewer clothes while having more outfits seemed like an oxymoron to me. But I still wanted to try it, so I called in an expert to show me how capsule wardrobes work.

Millie Bentley has been working as a designer and product developer for the last eight years at Aday, a capsule-wardrobe company that she says creates "minimalist wardrobes for maximal benefits."

"The idea is that you have fewer clothing items that you can do more with and travel further," Bentley said of capsule-wardrobe styling. "So we want clothes that people can wear in multiple situations and climates that really don't hold them back from doing what they love."

I asked Bentley to help me choose what to pack for my upcoming trip and we started by going over the details of my trip to the Great Smoky Mountains. I told Bentley that I'd be hiking, glamping, and exploring towns on foot, all while taking photos. I also told her the predicted forecast, which was 50-70 degrees Fahrenheit and rainy weather.

Since I was going on a reporting trip, Bentley and I started by packing all my work gear.

This included my laptop, my camera with two lenses, a tripod, a headlamp for night photography, device chargers, and a notebook.

My work gear took up about one-third of the space in my 32-liter backpack — leaving the other two-thirds of my bag for toiletries and clothing, which ended up being more than enough, to my surprise.

Staying clean and healthy while traveling is as important as my work gear. So I packed my toiletries next, as well as medications and a mini first-aid kit.

Bentley recommended bringing liquid toiletries like shampoo, conditioner, and face wash in reusable mini bottles to avoid purchasing single-use plastic bottles.

I was happy to follow this advice since she previously told Insider that packing reusable bottles was a more sustainable way to travel. According to a Greenpeace report published in 2022, only about 5% of all plastic was recycled in 2021 while the rest ended up in landfills, incinerators, or natural places.

Since I already had leftover travel-sized toiletries from previous hotel stays, I decided to finish those and refill them.

And, because I was going to be outside a lot, Bentley also suggested that I bring a cloth rag and biodegradable face wipes to "freshen up or take off any makeup or any dirt."

Lastly, I suggested laundry soap to wash my clothes in sinks, and Bentley agreed.

"I think that's a great idea," she said. "If there are puddles, or if you drop something that gets wet, it might start to smell."

By the time I finished packing my toiletries, I had a little less than half of the bag left for clothing.

When it was time to pack clothes, Bentley said her No. 1 tip for packing fewer items is focusing on quick-dry pieces, especially since my destination would be rainy.

"Quick-drying means you can wash the garment really easily and just hang it up," Bentley said.

Then, she explained the importance of including shirts that could be layered.

"You are going to want to layer as well. If the layer gets wet, you can take it off and can dry it quickly," she said.

She added that layering could help you feel more comfortable in a range of temperatures.

"Because you're fighting with the elements, you want a lighter layer that you are wearing underneath," she said. "So you've got the warmth, but then you can take it off if you get hotter."

I found it hard to follow Bentley's recommendation to wear neutral clothes because I love color. But Bentley said that packing neutrals makes it easy to style and match in different ways because every article of clothing goes together.

Lastly, Bentley asked if I felt confident that all my garments could be tightly rolled up. I told her that I'm quite short, so all my clothes are small.

"I always pack more of the smaller, lighter pieces than I would of the bigger, heavier ones," she added.

Bentley and I then moved on to T-shirts. She said I should bring two that could be worn on top of each other. This gave me three styling options with just two shirts — each by itself and also layered on top of each other — which I'd never considered before.

Following Bentley's advice, I selected two shirts made of thin, moisture-wicking materials. One was a plain gray shirt with a tight fit that could easily fit another shirt over it. The other shirt was a navy blue polo with orange accents, which was the closest I had to a neutral polo.

I chose shirts with different collars to give me more variety, too. I thought the gray shirt looked best underneath the polo, but it stood well on its own, too.

Most importantly for me, I thought these shirts were comfortable. They felt soft on my skin and were tight enough to trap in the heat without feeling constricting.

Bentley recommended I also bring a long-sleeve layer that I could wear on top of or underneath my T-shirts on cooler days.

"You could wear it open with your T-shirt underneath for a more casual look as well," Bentley said. "When clothes can be opened, draped, or tied, you've got this different look. And even though you perhaps haven't changed, you feel like you're in a different outfit."

For my long-sleeve layer, I selected a thin, light zip-up hoodie. Technically, it's a rash guard meant for swimming in cooler temperatures, but I thought the neutral color and lighter, quick-drying fabric would work perfectly for this trip since it's designed to get wet.

I could wear the rash guard underneath my polo, on top of each shirt separately and together, and tied around my waist. I was surprised by how different each look was, and it made me think of how I could wear my other clothes to make them feel different.

In that same vein, Bentley also suggested I bring a cardigan to layer for more formal activities, like going to dinner. I don't have many, so I brought my smallest, most neutral one. Bentley said I should go with a lightweight wool fabric, if possible.

"Because wool is very breathable and thermoregulating, it keeps you warm but can also keep you cool," she said.

Bentley said that I needed only two pairs of pants for my five-day trip

"Go for a pant to wear day-to-day that you'll be wearing in the rain. And then have a pant that you can relax in at the end of the day and perhaps go to dinner in, too." Bentley said. "Because you don't want to be wearing that pant that you've been wearing all day. You're going to want to dry them out."

For my daytime pants, I selected a pair of quick-dry joggers since they'd be easiest to air out after a day in the rain. When I hung them up each evening during my trip, they were dry by morning.

For my nighttime pants, I picked a pair of thin, black joggers that feel like scrubs but look more formal in dim lighting. I thought they would make me feel presentable when I went out, and cozy when I stayed in during my trip.

After packing shirts and pants, I asked Bentley about pajamas. She gave me ideas for clothing that could also add a layer to my daytime wardrobe.

"Leggings are very good. If it's cold in the morning, you can keep them on and layer them under your trousers," Bentley said, adding that I could take them off if it warms up

For a top, Bentley said I could bring another T-shirt so I'd have more options for layering in the daytime, too. I went with another quick-dry shirt that was slightly looser than the others I brought so it would be cozier to sleep in.

It wouldn't fit underneath my other shirts but could be layered over both, giving me two additional daytime looks.

Since Bentley recommended I rewear other clothing, I wondered about socks and underwear. In my previous backpacking experiences, I've found that socks tend to take up more room than most other items, but they also take days to air dry.

Bentley said I should bring a pair of socks and underwear for each day, but I could find more efficient ways to pack them.

"Underwear can be hidden in socks. Socks can be hidden in shoes or a random pocket," she said. "It's all about tucking them into different places to fill your bag."

I took Bentley's advice: I covered my camera and lenses with socks so they took up less room while serving another function. I was amazed by how much space I saved by rethinking the way I packed my backpack.

Bentley said my jacket should be my heaviest option, and that I should bring two and layer them on travel days.

"When I go away, I think about what takes up the most room and wear that when I'm traveling," she added.

I told Bentley that since my jacket options were limited, I wouldn't be able to stick with the neutral palette. But she said this was OK since the rest of my clothes were neutral. The jackets could serve as a "pop of color," she added.

I packed my biggest raincoat so it would fit on top of all of my layers. Underneath, I'd wear my smallest puffer. It's one of my thinnest jackets, but it also keeps me quite warm.

The raincoat's hard shell and adjustable Velcro straps could protect my inner sleeves, and the hood extended out beyond my glasses, to stop water drops from obscuring my vision.

Underneath my raincoat, the thin puffer would keep me warm and the rest of my clothes dry, and I couldn't believe I never thought to pair them before.

I typically travel with a single pair of shoes, so I wasn't surprised when Bentley told me I should only bring one because they're typically heavy.

"Your shoes should be comfortable with a look that you feel you can wear all the time," she said, recommending a neutral boot or trainer.

Since I expected rain, I picked a pair of black, water-resistant running shoes because they always keep my socks dry and I think they look presentable enough to wear out.

I'd also save room in my bag since I'd wear them on travel days and wouldn't have to sacrifice space for another pair of shoes.

With my clothes, toiletries, and work gear in the bag, I packed an umbrella for the rain and a reusable water bottle, per Bentley's suggestion.

When my packing was complete, I was surprised to see I still had space left at the top of my bag but chose not to add anything else, and left it empty for a lighter, more sustainable load.

After my conversation with Bentley, I felt confident that I had created a small, versatile wardrobe.

Bentley and I talked about wearing clothes in different ways, but I couldn't really visualize some of her tips until I was actually in the Great Smoky Mountains wearing the clothes that we chose together.

Ultimately, I was surprised to find that simply thinking about clothing in a different way can lead to ideas for more sustainable ways to live. Even though I brought less clothing for this trip than ever before, I never felt bored with my outfits like I have on previous backpacking trips.

In the future, I'll use these tips for all travel, big or small. And thanks to Bentley, I know I'll feel confident that I can enjoy a range of outfits with just a few articles of clothing.

In case you missed it, watch a replay of Insider's One Planet virtual event with the activist and artist Elijah McKenzie-Jackson.