The Need for Speed

 

If you have ever joined a Facebook group devoted to weight loss, investigated weight loss programs, diets or coaches, it's likely that you have been - and maybe still are- bombarded with all sorts of schemes that promise that they can show you how to lose weight without dieting or exercising or changing any of the habits that helped you gain the weight in the first place. Losing weight may not be easy (and can be much harder for some people than others) but it is not complicated. If you live in a calorie deficit (consuming fewer calories than you expend every day) you will likely lose weight. So most of us dismiss the most obvious nonsense as just that.

But what about the plans that promise rapid weight loss? 

The most common ways that people try to lose weight fast are by exercising a lot, and by following a”crash diet” or a very low-calorie diet of fewer than 800 per day. That sure sounds like a "calorie deficit" to me so why not, right? There is little doubt that such plans will shed pounds, and probably quickly. At least at first. But losing weight is only half the battle. The real challenge is keeping it off for good.

Most people who follow a diet regain half the weight they’ve lost after only a year. Even worse, nearly everyone who follows a diet regains all the weight they’ve lost after 3–5 years. That’s why experts often suggest losing weight at a slow but steady pace. Most studies show that people who lose weight at a slow but steady pace are more likely to keep it off long-term.

There are other issues associated with rapid weight loss as well. When you create a very large daily calorie deficit your body assumes it is starving and reacts accordingly. “When you lose weight too quickly, your body slows down its calorie-burning process,” explains endocrinologist and obesity specialist Dr. Marcio Griebeler. “That is your body’s way of trying to ensure you don’t starve. You might lose a good amount of weight right away, but your metabolism quickly goes into survival mode.” The change in your metabolism is a key reason why people regain weight after trying rapid weight loss plans. When you go back to eating a regular diet, your metabolism isn’t used to that many calories — and the pounds come back. Other risks include undesirable muscle loss, nutritional deficiencies and gallstones.

So while it is certainly possible to lose weight fast by creating a large daily calorie deficit, such an approach is unhealthy, cannot be maintained and increases the likelihood of regaining any lost weight quickly as well.

What is a safe rate for long term weight loss? Most experts recommend a rate of 1 or 2 pounds per week (that would be a calorie deficit of about 500 - 1,000 kCal per day) and in any case not consuming less than about 1,200 calories daily. This might seem like a frustratingly slow pace if you want to lose a significant amount of weight. But look at it this way. You probably didn't gain the weight in a week or two, it probably took years. Why would you expect to lose it that fast?