Yo-Yo Dieters Can Lose As Much Weight As Those Who Don’t

This is the story of Marilyn and Catherine.

Marilyn* is 58 years old with a BMI of 33 and has struggled with her weight for most of her life. Not counting pregnancies, Marilyn, has been losing and regaining weight since her early twenties. Although she is usually up and down five to ten pounds as she tries one diet or commercial program after the other, she did indeed lose a very significant amount of weight (well over 20 lbs) on at least three occasions (only to put them back on again).

Catherine* is also 58 years old, is slightly lighter than Marilyn with a BMI of 30, and has never dieted or lost weight before in her life.

Both Marilyn and Catherine (together with 437 other post-menopausal women) decided to take part in a weight-loss study led by Canadian Obesity Network Summer Bootcamper Caitlin Mason, now working with colleagues at the Fred Hutchinson Cancer Research Centre in Seattle, WA.

The participants in the study were randomized to one of four groups (diet, exercise, diet + exercise, or control).

Oddly enough Marilyn and Catherine both end up in the diet + exercise group, and even more interestingly, both women ended up losing almost exactly the same amount of weight.

In fact, Marilyn (the weight cycler) lost 12%, slightly more that the 10% lost by Catherine (the non-cycler).

This was pretty much the result in every group. Irrespective of wether or not the participants had a history of weight cycling or not, the weight loss in controls (0% vs. 0%), diet only (-8.4% vs. -9.1%), or exercise only (-2.4 vs. -2.4%) were almost exactly the same.

In addition, there were no differences between Marilyn and Catherine in their improvements in blood pressure, glucose control and other metabolic variables, showing that a previous history of weight cycling did not diminish the benefits of weight loss.

Thus, the study clearly shows that post-menopausal women with a history of dieting are as capable of losing weight (with the same health benefits) as women, who do not have a history of weight cycling.

So, if weight cycling does not make it harder to lose weight – why worry about a yo-yo dieting?

As I am sure my readers will hasten to point out, there are many other reasons why weight cycling is not a good idea.

Some of these reasons may become clearer tomorrow, when we take a closer look at Marilyn’s and Catherine’s health before they entered this study – so stay tuned.

Kelwona, BC

*The characteristics of Marilyn and Catherine are based on the average characteristics of the non-cylcer and severe-cycler participants in this study.

ResearchBlogging.orgMason C, Foster-Schubert KE, Imayama I, Xiao L, Kong A, Campbell KL, Duggan CR, Wang CY, Alfano CM, Ulrich CM, Blackburn GL, & McTiernan A (2013). History of weight cycling does not impede future weight loss or metabolic improvements in postmenopausal women. Metabolism: clinical and experimental, 62 (1), 127-36 PMID: 22898251