But aside from being a lofty goal you make for yourself, it's pretty hard to achieve; most people who set out to lose weight don't, or if they do they gain it back. Plus, people tend to go overboard with these promises to themselves, signing up for expensive gym memberships, stocking up on pricey green juices, and buying the latest fitness tracker. Here, too, you run into a specificity problem -- if you just say you're going to "lose weight," how will you know what to shoot for? What's too much, too little, and just right? You're more likely to do nothing at all if your goal is too broad.
The best way to actually lose weight and keep it off is to start making targeted, specific lifestyle changes. And starting out slow is best: swapping out processed snacks and meals for fresh produce, committing to a couple days a week of activity, drinking at least 64oz of water a day. If you're obsessed with the number on the scale (which you shouldn't be), then keep your goals realistic. Most people can lose about 0.5-2lbs a week, so aiming for a 20lb weight loss in a month, while doable, isn't as sensible as, say, 5 or 10lbs.