Researchers tracked the hormone levels of 20 obese people who went on an ultra low-calorie diet for two months, losing an average of 13 percent of their body weight. The subjects then went on a less extreme weight-maintenance diet for a year and their weights stayed stable.
The researchers found that the hormone ghrelin, which makes you feel hungry, spiked by 23 percent after the subjects’ initial weight loss.
That’s right: As if losing weight wasn’t hard enough, the researchers say that your body’s survival instincts fight your efforts to drop pounds by sending your appetite into overdrive.
But over the next year, the subjects’ ghrelin levels dropped back down by 7 percent.
Your body seems to adapt to its new weight slowly over the course of a year, says study coauthor Signe Sørensen Torekov, Ph.D. As you get used to your new weight, the production of your hunger hormones taper off .
The researchers also found that two types of hormones that help you feel full—GLP-1 and PYY3-36—increased steadily over the year following the subjects’ weight loss.
The researchers think that extra body fat may hinder your cells’ ability to produce those satiety hormones, so losing the fat and keeping it off could allow the hormone production to return to normal.
The findings suggest that if you can maintain your goal weight for a year, you’ll start to feel less hungry on an daily basis, so maintaining your weight will become easier, Torekov says.
Although the study was very small, Torekov thinks the results would hold true for most people who lost a similar amount of weight.