1. Stand up straight
These aren't frivolous pieces of advice either, both are usually the first hints beauty stylists give to their clients on photo-shoots. What's more interesting about the above is that they do a great job of exposing the disconnect between what we think of health as, and what we believe we need to do to get there.
For most people, the ultimate goal of weight-loss is to look better. That's what it means to be healthy. Ideally, people want to feel better too, but that's more secondary of a goal. You might even say looking good is a prerequisite to feeling good.
However, as the above two tips go to show, you don't need to actually lose weight to look better. There are a whole series of tips and hacks that will improve your appearance. Most people (including myself), would have a tough time seeing the truth in this if they think their weight is the barrier to their presentability. The problem with this view is that it sets what you could call a negative goal. Instead of trying to achieve something (losing weight for its intrinsic benefits), you end up trying to make up for what's perceived as an undesirable trait (you have to lose weight to look less bad). And so it's no wonder that only five percent of people who lost weight manage to keep it off for more than a year. If your goal is constantly pit in negative terms, you can never win. If you can't win, why even try?
In a perfect world, the whole weight-loss scenario would be reversed: instead of perceiving the current body to be a hindrance, do your best to look and feel good now. Then, attempt to lose weight so that you have more to work with.
This is terrible advice because it requires a person to completely shift their mindset, which is a product of years and years of social conditioning. My real advice is to follow the first two pointers at the top of this post. You'll feel better for it, and I'm sure it'll make you stick to your goals better.