NBC Nightly News recently reported that a new study gives us clues of “why it’s so hard to keep weight off once you have lost it.”

The New York Times (Subscription Publication) reports, “For years, studies of obesity have found that soon after fat people lost weight, their metabolism slowed and they experienced hormonal changes that increased their appetites.” Researchers “hypothesized that these biological changes could explain why most obese dieters quickly gained back much of what they had so painfully lost.”

The new study, published in “the New England Journal of Medicine, helps explain why roughly four in five dieters wind up gaining back lost pounds within a year or two of losing them – and, sometimes, pack on a few extra pounds for good measure,” the Los Angeles Times explains.

The AP adds, “The findings suggest that dieters who have regained weight are not just slipping back into old habits, but are struggling against a persistent biological urge.”

HealthDay reports that in the study, “Australian scientists found that after overweight and obese patients followed a low-calorie diet for 10 weeks, their appetite and hunger hormone levels changed. While some hormone levels increased and others went down compared to before they dieted, nearly all of the changes favored the body’s efforts to regain the lost weight.”

In particular, investigators examined the circulating levels of a number of “hunger hormones,” including “leptin, ghrelin, peptide YY, gastric inhibitory polypeptide, glucagon-like peptide 1, amylin, pancreatic polypeptide, cholecystokinin, and insulin at three time points: baseline, 10 weeks, and 62 weeks,” MedPage Today reports.

“One year later, there were still significant differences from baseline in the mean levels of leptin (P<0.001), peptide YY (P<0.001), cholecystokinin (P=0.04), insulin (P=0.01), ghrelin (P<0.001), gastric inhibitory polypeptide (P<0.001), and pancreatic polypeptide (P=0.002).”

Notably, “all of these changes would be expected to facilitate weight regain, the researchers said, except the change in pancreatic polypeptide.”

So, what can one do to fight these “hunger hormones”?

• Exercise daily,
• Eat a nutritious diet that is high in fruits and vegetables and “good carbs” (whole grains and high fiber foods),
• Emphasize “good fats” (PUFAs) instead of “bad fats” (saturated and trans-fats),
• Emphasize plant based proteins, and
• Get plenty of sleep.