That's where the ultralight philosophy begins: Pack smarter, go further (and faster), and experience more. Traveling light also puts less stress on your body, reducing fatigue and enabling you to hike more regularly - for many years to come.
Your base weight is the total weight of your gear kit - that's your backpack, the gear inside it, and any gear attached to the outside - excluding consumables. Consumables are food, water, and fuel, and they're excluded from your base weight because the amount varies by trip length and conditions.
For ultralighters who take these weight limits as gospel, there's no expense too great or method too creative when it comes to paring down an ounce (or even a few grams). And if the truly dedicated can't find the gear they want, they might make their own! For others, especially those just starting out, the numbers are there simply to provide a benchmark for where you are now - and what's possible with some research, experience, and investment.
How much do you value comfort and convenience? For example, would you roll up your jacket and use it as a pillow if it meant saving space in your pack? How does your skill level relate to your safety needs? Know your limits. If the unexpected occurs, are you experienced enough to improvise with what you have?
Finally, think about the items you've carried in the past and didn't end up using. No one can make all the right choices from the beginning, but every trip and the errors made along the way teach you how to modify your pack in the future.
Weigh everything. The first piece of gear any ultralighter should have won't come on any trips: your scale. Any $20 digital kitchen scale will do - just make sure it is accurate to a tenth of an ounce (or single grams). Create a spreadsheet where you can compile your packing list and the individual weights, and determine which changes will make the biggest impact. An online document is easy to share and compare with others, but if pencil and paper are more your thing, those work too!
Rethink your list. This step takes knowing the difference between needs and wants. Do you need that deck of playing cards? The mug in addition to a Nalgene bottle? The full-size camera? The extra clothes? Some gear you might bring car camping without much thought can add unnecessary pounds when you're backpacking and find yourself on the move for most, if not all, of the daylight hours.
Repackage. Travel-size items from the store can come with a lot of extraneous packaging, and pre-assembled kits may include stuff you don't need. Repackage these before your trip, and remember that a simple Ziploc bag is a great place to store small items.
Live multi-purpose. This is an easy way to cut weight and spend less money doing it. Trekking poles can be used to support your shelter. A pot can double as a bowl or cup at mealtime. A bandana can be worn as a hat or scarf, or used as a potholder, bandage, or towel for washing up.
Sharing is caring. If you're traveling with a friend or a group, split community gear (like the tent, water filter, and stove) evenly between your packs to lighten each one and ensure you don't bring too much of any one thing.
Skills go a long way. Learn how to set up an ultralight shelter, like a tarp, and you could save yourself a couple of pounds. Learn about campsite selection, and you could save yourself a night of harsh winds and mosquito bites. Learn how to find water in the backcountry, and you won't have to carry as many bottles. If you have a big trip coming up, test your gear (and those new skills) on a shorter trip first.
Replace as needed. The materials commonly used to make outdoor gear have changed in recent years, and you could save a substantial amount of weight by replacing outdated items. Start by swapping out your heaviest, bulkiest gear, and think about which new items are best for your circumstances. Do you need them to be durable? Versatile? Budget-friendly? Are you looking for a minimalist item or one rich with features?
Feet first. Many backpackers choose to replace hiking boots with hiking or trail running shoes, which are often lighter and less expensive. Because the weight on your feet requires about five times as much energy to move as the same amount of weight on your back, minimizing your footwear can immediately reduce the number of calories you burn and allow you to do more miles.
Pack smart. While it's important to be prepared and a lighter pack should never come at the expense of safety, don't get caught up in "What if?" scenarios. If the forecast says blue skies, why bring a rain jacket or pack cover? Do you need that 0-degree sleeping bag in the early fall? Pack realistically based on the conditions typical to the area you're visiting.
Ultralight doesn't always have to mean bare bones. If you want to bring luxury items that make your time in the wild more enjoyable (like a sketchbook, collapsible fishing rod, pair of binoculars, tablet, ukulele, or flask of bourbon), don't let anyone stop you. Having a light pack to start with makes adding these items that much easier.