If you’re someone who’s trying to lose weight, you’ve probably seen your body yo-yo back and forth between weight loss and gain. In fact, keeping weight off after it’s gone is often the hardest part of cutting pounds in the long run. Research has shown this is likely because the body fights weight loss efforts by using clever tactics to bring that weight back even if you don’t boost your calories. But new research soon to be published has found that keeping weight off in the long run isn’t a struggle forever. Their findings indicate that making it to a year without putting pounds back on may be enough to make lost pounds stay that way.
Why is it so hard to keep weight off once I lose it?
It used to be thought that losing weight was as simple and straightforward as cutting calories and exercising more. But experience with this typical weight loss regimen has shown that what causes the body to lose and gain weight is much more complicated. Past research has shown that people who lose weight tend to regain it because the body fights weight loss using a variety of hormonal signals to adjust how much energy is burned and stored. Regaining weight in this way probably kept our ancestors from burning off too much energy when food was scarce. In our modern world where food is everywhere, though, these protective mechanisms can act as a major barrier to getting to a healthy weight.
What changes are happening in the body when I lose weight?
- A hormone called GLP-1 works together with hormone peptide YY (PYY) to control your appetite and when you feel satisfied during and after a meal.
- GIP is involved in determining much of the fat your body makes and takes in through your diet is stored for later use.
- Ghrelin is a hormone that controls feelings of hunger. It’s thought that this hormone is part of the reason you feel so hungry when you first lose weight and cut calories.
- Glucagon is a hormone made by your pancreas that helps control blood sugar levels and some research has shown it might help lower your appetite.
- Insulin is a hormone commonly known as being involved with diabetes, but it also plays a role in your appetite and helps regulate glucagon levels in the body.
There’s been interest in these hormones because they seem to differ between people who are obese and people who are not that keep obese people obese and non-obese people from gaining weight too easily.
How was this team’s approach to weight loss different?
This group of researchers wanted to see if people who lost weight by dieting might be able to change their hormonal response if they kept the weight off for long enough. Would obese people eventually end up with the hormonal profile of thinner people if they kept the weight off for long enough? Or would their hormones would always fight weight loss, no matter how long those pounds had been gone?
To answer those questions, they recruited 20 obese individuals between 18 and 65 and put them on a low-calorie diet that consisted only of 810 calories worth of powdered food per day. They stayed on that diet for eight weeks and lost around one sixth of their total body weight. After that, the participants stayed on a lower calorie diet of normal food and continued to receive dietary counseling. If their weight started to rise at any point, up to two of their meals could be replaced by the low calorie powder to help lose that new weight. The participants had their blood hormone levels checked at the beginning of the study, after losing weight, and after one year of keeping the weight off.
What did the researchers discover?
The team found that after a year of keeping the weight off, the participants hormone responses to food had shifted to be more similar to the responses of a non-obese person. This included hormone changes that would help them feel full earlier and that would decrease how often they felt hungry on their new, lower-calorie diet. All of the hormones they tested except glucagon were affected by the weight loss. The researchers think this shows that these individuals have reached a new “set point” so that their body feels comfortable at this new weight rather than feeling the need to push their weight up to where it was before they lost weight.
What does this mean for me?
This study shows that your body eventually adjusts to lost weight, but that it might take a while. Importantly, it was key for the participants to continue to diet when their weight started to creep back up so that they could prevent their body from getting used to that old weight again. The researchers think this shows that, while it might be hard to keep the weight off, it gets easier once you’ve been at your new weight for long enough.