Many people who began the New Year with a resolution to lose weight bought into a quick-fix restrictive diet. And they saw results. A lot of crash diets allow for 5 or 10 pounds of weight-loss in just a couple weeks.

The problem is that overly restrictive diets aren’t possible long-term, and by now a lot of resolutions have fallen by the wayside. People have resumed their normal eating habits, and many New Year’s dieters have gained back everything they’d lost and then some. What a disappointment.

The truth is that quick-fix; overly restrictive diets set people up for failure. The calorie-restriction necessary for quick weight-loss slows down your metabolism 10-15%. For example, if a dieter skips breakfast to cut calories, her metabolism basically goes into hibernation. Everything slows down.

The dieter sees the slow-down when the scale refuses to budge, and she feels the slow-down in her everyday life. She is sluggish, she has brain fog, and she doesn’t feel like doing anything—especially exercising. While dieting, you are less likely to get metabolism-boosting and muscle-building exercise. In fact, some super-low-calorie diets recommend that you stop exercising! We have to eat well in order to fuel busy, active lifestyles.

Starvation dieting lowers your metabolism not just today but over the long-term as well.  When you lower your calories too much, you end up losing muscle. Three pounds of muscle gained or lost changes your metabolism by 7%. If you gain muscle, for example through strength training, your metabolism increases and you can eat more without gaining weight. That’s one great benefit of strength training.

But when you lose muscle through crash diets, your metabolism drops. Then, when you gain back the weight you lost (because that is what happens with crash diets), most of what you gain back is fat. So even if the number on the scale is not higher than when you started, you are actually fatter (you are carrying more fat). And your metabolism is lower because of the muscle that you lost in this round of dieting.

The best thing for everybody to do—especially mid-lifers who often have an age-related metabolic drop even before starvation diets and muscle-loss—is to swear-off crash diets forever. They don’t work for weight loss in the long term; in fact, the main effect of most crash diets is the two-pronged metabolic drop described above. One: your metabolism drops short-term when you don’t eat. Two: your metabolism drops long-term when you lose muscle.

A better approach is to eat the low-glycemic way. The glycemic index is a measure of the affect of foods on your blood-sugar levels. Foods with a high glycemic value rapidly raise your blood-sugar level, giving you a “sugar high,” or a spike in energy. But the high doesn’t last. Soon you crash, get tired, and crave another sugar rush. Odds are that you will jump on for another cycle—blood-sugar spike, blood-sugar drop, and so on.

When you eat on the lower end of the glycemic index (protein, vegetables, and so on), your blood-sugar will be steadier, and you will feel more consistently energized, alert, and productive throughout the day. Your metabolism will not crash, you will have energy for exercise, and you will lose weight slowly and steadily.  

What do you think of that phrase “slowly and steadily”? Does it sound like hard work? It can be. Does it sound boring? It doesn’t have to be. It may help to reframe “slow and steady” weight-loss. Try calling it “permanent and sustainable” weight-loss. Does that sound better?

If you are feeling like you have already failed your resolution to lose weight, don’t give up!  Swear-off crash diets forever, learn about the glycemic index, and put what you learn to work. Change your lifestyle. And don’t be one bit discouraged by January’s crash diet failure: You didn’t fail; the diet failed. Diets don’t work, but if you work, then you can lose weight—and keep it off for good!