Yesterday, I wrote about new research showing that you can reverse Type 2 diabetes. All you have to do is lose weight, and keep it off.

But, as any yo-yo dieter knows, that’s easier said than done. The vast majority of people who lose weight regain what they lost (and often more) within twelve months.

Inevitably, that’s because people (especially we impatient folks here in the US) tend to lose weight through inherently unsustainable approaches. Sure, you can eat cabbage soup for a few weeks, and drop ten pounds. But unless you’re planning to eat just cabbage soup for the rest of your life (and for a slew of reasons, from malnutrition to culinary misery, I wouldn’t recommend it), you’re going to return to your normal eating patterns eventually. And the scale will swing back up once you do.

The solution, then, is what I think of as the ‘toothbrush rule’.

Most of us are well aware that toothbrushing isn’t a short-term intervention. Instead, we’ve accepted the idea that we need to keep brushing our teeth as long as we’d like to still have teeth.

Nutrition (and health in general) works the same way. The only things that are successful in the long-haul are things we’re able to keep doing over that long-haul.

That means, first, that if you can’t imagine doing something for the next ten years, it’s a waste of your time and energy to try it for the next ten days.

And second, it means that when you’re thinking about improving your nutrition, exercise and lifestyle, you should be thinking in terms of habits, about small relatively painless things you can do daily until they become second nature.

Only when you turn health into habit can you keep it going indefinitely. That’s why research has shown the single best predictor of continuing to maintain weight loss is how long you’ve already maintained that weight loss.

And it’s not just your brain that adapts to those kinds of long-term habits; the rest of your body is a highly adaptable system, and eventually it will swing around to back you up, too. For example, right after you lose weight, your pancreas secretes large amounts of ghrelin, a hormone that drives the feeling of hunger. But research has shown that if you maintain the weight loss, ghrelin levels (and therefore your sense of hunger) slowly drop back to where they were before you lost weight. In other words, keeping off the weight gets easier the longer you keep it off.

So, if you want to get healthy, and to stay healthy, think about the toothbrush rule. Build your approach based on sustainable habits, and only take on things that you’re willing to keep doing as long as you’d like to keep your health.