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TOPLINE:
People who regain lost weight may be biologically driven to do so via hyperphagia, or an insatiable hunger, a study in mice suggested.
METHODOLOGY:
- Researchers developed a male mouse model of reversed dietary obesity (ReDO) by feeding mice a high-fat diet for 16 weeks, then putting them on a calorie-restricted diet until their body weight matched that of control mice.
- ReDO mice were then divided into four categories: one group had unrestricted access to food after calorie restriction, and one was perpetually matched to the food consumption patterns of a normal-weight control group.
- The other two groups’ diets matched those of normal-weight mice for 8 or 28 days, after which they ate ad libitum.
TAKEAWAY:
- The formerly obese mice allowed to eat ad libitum displayed persistent hyperphagia compared with control mice and the perpetually pair-fed mice, and their tendency to overeat lasted up to a month after having maintained a lower weight with a standard diet.
- Mice that gained weight quicker on the high-fat diet regained the most weight, suggesting a potential predictor of susceptibility to weight regain.
- Only mice whose food consumption patterns were perpetually matched to those of the control group maintained their weight loss.
- Compared with lean control mice, ReDO mice appeared to be driven to reclaim an upwardly shifted bodyweight set point.
IN PRACTICE:
“Mice appear to have a long-lived physiological drive to reclaim an elevated body weight. This is relevant for humans in that, although they may successfully lose weight, our study suggests they may still have to resist a biological drive to return to an elevated bodyweight set point in order to maintain weight loss,” said the lead author of the study in a press release.
SOURCE:
Frankie D. Heyward, PhD, UT Southwestern Medical Center, Dallas, led the study, which was published online in iScience.
LIMITATIONS:
The study was limited in that it only included male mice and did not assess whether ReDO mice pair-fed for longer than 1 month might exhibit eventual weight regain.
DISCLOSURES:
The research was funded by grants from the US National Institutes of Health. The authors declared having no competing interests.
Marilynn Larkin, MA, is an award-winning medical writer and editor whose work has appeared in numerous publications, including Medscape Medical News and its sister publication MDedge, The Lancet (where she was a contributing editor), and Reuters Health.
