Hormones regulating when a person feels hungry or sated do not rapidly adjust to weight loss, which may be a factor in the yo-yo effect observed among dieters, researchers found.
One year after losing weight, levels of appetite-regulating hormones didn't revert to baseline levels, Joseph Proietto, PhD, of Heidelberg Repatriation Hospital in Australia, and colleagues reported in the Oct. 27 issue of the New England Journal of Medicine.
The findings suggest that the "high rate of relapse among obese people who have lost weight has a strong physiological basis and is not simply the result of the voluntary resumption of old habits," Proietto and colleagues wrote.
- Explain that an Australian study found persistent changes in hormone levels affecting hunger and satiation one year after completion of a 10-week weight loss program for overweight and obese individuals.
- Note that failure of these appetite-regulating hormones to return to baseline levels despite regaining of some of the lost weight suggests a physiologic basis for problems of weight gain following diets in the obese.
It's well established that heavy patients who lose weight dieting often fail to keep the pounds off, the researchers explained.
Studies have shown that restricting calories can lower levels of the hormones leptin -- which tells the brain that the body is full -- and ghrelin -- which stimulates hunger.
There are changes in circulating levels of hormones involved in body weight regulation as well, but it's not clear whether these changes persist over time.
Proietto and colleagues enrolled 50 overweight or obese patients in a 10-week weight-loss program that involved a very low energy diet.
They looked at circulating levels of 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.
They also evaluated subjective ratings of appetite.
In the intention-to-treat analysis, the mean weight loss at the end of 10 weeks was 13.5 kg (about 30 lbs), and the researchers assessed hormone data from the 34 patients who completed the full trial.
The researchers found that at 10 weeks, weight loss led to significant reductions in leptin, peptide YY, cholecystokinin, insulin, and amylin (P<0.001 for all except amylin, which was significant at P=0.002).
There were also significant increases in levels of ghrelin (P<0.001), gastric polypeptide (P=0.004), and pancreatic polypeptide (P=0.008) at that time point.
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).
All of these changes would be expected to facilitate weight regain, the researchers said, except the change in pancreatic polypeptide, which reduces food intake. Weight regain had begun in these participants although they still had an overall net weight loss from the beginning of the study.
Proietto and colleagues also found a significant increase in subjective appetite with weight loss. Mean ratings of hunger, desire, and urge to eat, and prospective consumption were significantly higher at both 10 and 62 weeks than at baseline, they reported (P<0.001).
"In obese persons who have lost weight, multiple compensatory mechanisms encouraging weight gain, which persist for at least one year, must be overcome in order to maintain weight loss," they wrote. "These mechanisms would be advantageous for a lean person in an environment where food was scarce, but in an environment in which energy-dense food is abundant and physical activity is largely unnecessary, the high rate of relapse after weight loss is not surprising."
They said the findings also suggest that there's an elevated body weight "set point" in obese patients, and efforts to lower weight beyond this point are "vigorously resisted."
Thus, managing obesity will require treatments to "counteract these compensatory mechanisms and reduce appetite."
They noted that bariatric surgery has been shown to have positive effects on hunger-mediating hormones, but the procedure isn't readily available to most patients.
The study was limited by its high attrition rate, which the researchers said is typical for long-term weight loss studies.
The study was supported by the National Health and Medical Research Council in Australia, the Endocrine Society of Australia, the Royal Australian College of Physicians, and the Sir Edward Dunlop Medical Research Foundation.
A co-author reported relationships with Novo Nordisk.
New England Journal of Medicine
The text passage describes a study on the hormonal changes that occur in overweight and obese individuals after weight loss and how these changes may contribute to the difficulty in maintaining weight loss over time. It does not contain any mathematical questions or answers.
no_question
Given a text passage, determine:
    1. If it contains a mathematical question (including word problems or calculations)
    2. If an answer to that mathematical question is provided in the text

First, describe the content structure you found in 1-2 sentences.

Then provide your analysis in the following format:
TYPE: <one of the following values>
- NO_QUESTION
- SINGLE_QUESTION
- SINGLE_QUESTION_WITH_ANSWER
- MULTIPLE_QUESTIONS
- MULTIPLE_QUESTIONS_WITH_ANSWERS
system
Hormones regulating when a person feels hungry or sated do not rapidly adjust to weight loss, which may be a factor in the yo-yo effect observed among dieters, researchers found.
One year after losing weight, levels of appetite-regulating hormones didn't revert to baseline levels, Joseph Proietto, PhD, of Heidelberg Repatriation Hospital in Australia, and colleagues reported in the Oct. 27 issue of the New England Journal of Medicine.
The findings suggest that the "high rate of relapse among obese people who have lost weight has a strong physiological basis and is not simply the result of the voluntary resumption of old habits," Proietto and colleagues wrote.
- Explain that an Australian study found persistent changes in hormone levels affecting hunger and satiation one year after completion of a 10-week weight loss program for overweight and obese individuals.
- Note that failure of these appetite-regulating hormones to return to baseline levels despite regaining of some of the lost weight suggests a physiologic basis for problems of weight gain following diets in the obese.
It's well established that heavy patients who lose weight dieting often fail to keep the pounds off, the researchers explained.
Studies have shown that restricting calories can lower levels of the hormones leptin -- which tells the brain that the body is full -- and ghrelin -- which stimulates hunger.
There are changes in circulating levels of hormones involved in body weight regulation as well, but it's not clear whether these changes persist over time.
Proietto and colleagues enrolled 50 overweight or obese patients in a 10-week weight-loss program that involved a very low energy diet.
They looked at circulating levels of 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.
They also evaluated subjective ratings of appetite.
In the intention-to-treat analysis, the mean weight loss at the end of 10 weeks was 13.5 kg (about 30 lbs), and the researchers assessed hormone data from the 34 patients who completed the full trial.
The researchers found that at 10 weeks, weight loss led to significant reductions in leptin, peptide YY, cholecystokinin, insulin, and amylin (P<0.001 for all except amylin, which was significant at P=0.002).
There were also significant increases in levels of ghrelin (P<0.001), gastric polypeptide (P=0.004), and pancreatic polypeptide (P=0.008) at that time point.
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).
All of these changes would be expected to facilitate weight regain, the researchers said, except the change in pancreatic polypeptide, which reduces food intake. Weight regain had begun in these participants although they still had an overall net weight loss from the beginning of the study.
Proietto and colleagues also found a significant increase in subjective appetite with weight loss. Mean ratings of hunger, desire, and urge to eat, and prospective consumption were significantly higher at both 10 and 62 weeks than at baseline, they reported (P<0.001).
"In obese persons who have lost weight, multiple compensatory mechanisms encouraging weight gain, which persist for at least one year, must be overcome in order to maintain weight loss," they wrote. "These mechanisms would be advantageous for a lean person in an environment where food was scarce, but in an environment in which energy-dense food is abundant and physical activity is largely unnecessary, the high rate of relapse after weight loss is not surprising."
They said the findings also suggest that there's an elevated body weight "set point" in obese patients, and efforts to lower weight beyond this point are "vigorously resisted."
Thus, managing obesity will require treatments to "counteract these compensatory mechanisms and reduce appetite."
They noted that bariatric surgery has been shown to have positive effects on hunger-mediating hormones, but the procedure isn't readily available to most patients.
The study was limited by its high attrition rate, which the researchers said is typical for long-term weight loss studies.
The study was supported by the National Health and Medical Research Council in Australia, the Endocrine Society of Australia, the Royal Australian College of Physicians, and the Sir Edward Dunlop Medical Research Foundation.
A co-author reported relationships with Novo Nordisk.
New England Journal of Medicine
user
The text passage describes a study on the hormonal changes that occur in overweight and obese individuals after weight loss and how these changes may contribute to the difficulty in maintaining weight loss over time. It does not contain any mathematical questions or answers.

TYPE: NO_QUESTION