The Hare and the Tortoise: Aesop's Fable and Weight Loss
Does rapid weight loss necessarily lead to weight regain?
Posted March 11, 2013
Most everyone knows Aesop’s fable of The Hare and the Tortoise: a hare makes fun of a tortoise for moving so slowly. The tortoise challenges him to a race. Feeling quite sure of himself and seeing how far ahead of the tortoise he is initially, the hare decides he has time for a rest. When the hare finally awakens from his nap, it is too late and the tortoise has already won the race. The moral: “Slow and steady wins the race.”
What about with weight loss? Is there an optimal rate at which we should lose weight? Is “slow and steady” the secret to avoiding weight regain? Weight regain, after all, is a serious problem. Even when dieters lose significant amounts of weight, they typically regain one-third to one-half of their lost weight in the year following treatment. (Perri et al, 2008, Archives of Internal Medicine). Eventually, over the next several years, most people regain all their lost weight and then some.
In his excellent article, “Myths, Presumptions, and Facts about Obesity,” published recently in The New England Journal of Medicine (January 31, 2013), Dr. David B. Allison, Quetelet Endowed Professor of Public Health at the University of Alabama (Birmingham), and his colleagues found that it is actually a myth that “large, rapid weight loss is associated with poorer long term weight loss outcomes, when compared with slow gradual weight loss.” Using an evidenced-based model, Allison et al found seven myths about obesity that are “false and scientifically unsupported beliefs” but remain “pervasive in both the scientific literature and the popular press.”
This particular false and persistent belief most likely arose from studies that involved dangerous, very low calorie and “nutritionally insufficient” diets (VLCD) of fewer than 800 calories a day. Years ago, those diets, particularly when not supervised by a physician or nutritionist, had been associated with severe medical (e.g. cardiac) complications and even death. Characteristically, when patients do lose weight rapidly by severe caloric restriction, they are likely initially losing water and even muscle mass, particularly if they are not getting sufficient amounts of protein in their diets. Typically, most textbooks recommend 1 to 2 pounds a week as a safe amount to lose. This is often based on the fact that roughly, there are 3500 calories to a pound: to lose a pound, you have to eliminate 500 calories a day from your diet and to lose two pounds a week, 1000 calories a day. (Of course, as you lose weight, your body compensates and requires fewer calories for maintenance.) For most people, cutting all those calories is difficult enough, particularly in our obesogenic environment, without cutting even more.
Steady weight loss is not necessarily less likely to prevent weight regain for everyone. Astrup and Rössner, for example, in Obesity Reviews (2000), found that a greater initial weight loss, as long as it was the first step in a weight management program, could result in “improved sustained weight maintenance.” As a result of their survey of the literature, these authors concluded that obese patients should not necessarily be encouraged to set lower weight-losing goals. In fact, losing weight more rapidly can provide considerable psychological reinforcement for the dieter. What tends to prevent weight regain, though, is adherence to a long-term program--what’s called a “continuous care” model since obesity (and weight control) are chronic problems for those so genetically challenged. For most, long-term follow-up--whether face-to-face or even by telephone or computer-- provides the much needed accountability, i.e., consistent monitoring of what we eat, how much we exercise, and and what we weigh as measured on a scale. Furthermore, what also is more likely to lead to maintenance of any weight loss (i.e. avoiding weight regain) is continuing to practice lifestyle interventions such as daily exercise and watching our diet (including monitoring of calories) indefinitely. More recently, Nackers et al (2010) also found that those who lost more weight initially in the first six months were more successful long-term and were not more susceptible to regaining their lost weight over 18 months of follow-up. In this study, those who lost weight most rapidly were more likely to have greater adherence to the program (e.g. attended more follow-up sessions, completed more food records, eaten fewer calories, and exercised more) than those who lost weight the most slowly. And they agree that losing at a slow rate, may be “less reinforcing to participants than losing at a moderate or fast initial rate.”
Bottom line: The recommendation to lose weight more slowly works for some but may actually interfere with long-term goals and successful weight maintenance for others. It sometimed depends on how you lose the weight and there are substantial genetic differences among people. We don’t always know why some people lose weight more slowly than others. Allison and his colleagues, though, note “heritability is not destiny!” Environmental factors can be significant contributors to weight control as well.