Study author Susan Roberts defines "sensible" as no less than 1,200 calories a day for women, down from the 1,500 typically advised for a slower diet. In her study, those who tried to cut their calories down to this lower level had lost about the same amount of weight after a year as more conventional dieters, despite the assumption that crash dieting would cause binging and rebound weight gain. Roberts adds that "disinhibited eaters," those who easily break their diets when presented with the opportunity, "did really badly" on the more moderate plan. She says a dramatic change may be easier for some people than moderation, and "the trouble with slow diets is people tend to feel they are getting nowhere and give up. Fast keeps you excited and feeling like you're making progress."
Unsurprisingly, this crash dieting research has its detractors. Fat Is a Feminist Issue author Susie Orbach says, "diets depend on failure. They need to fail, otherwise there would be no repeat customers." And eating-disorder consultant Dr. Peter Rowan adds, "even a sensible weight-loss diet can trigger an eating disorder in someone who is vulnerable, but there is evidence to suggest that the more severe the weight loss, the more likely the diet is to trigger an eating disorder."
Even if crash dieting is more "effective" (i.e. promotes more sustained weight loss) than previously thought, we're not sure we can get behind the idea. Times writer Olivia Gordon describes her days of crash dieting thus:
I had a green salad and no cake for dinner on my 16th birthday. I lived through "Smashgate," a regime of Smash mashed potato, for days, until I realised that it was about 10 times as calorific as I'd thought. At university, it was all about calorie counting - anything from 700 to 1,200 calories a day. In my first job, I worked through a haze of starvation on the simple but deadly "stone in four days" plan. I picked Thursdays for the first night of a fast, so I could offset dinner hunger pangs by late-night shopping at Topshop.
Gordon says that with Roberts's new research, "we could all be about to head back to the weird world of crash dieting" — but we'd still rather have cake.
Can Crash Diets Be Good For You? [Times of London]