People who stop GLP-1 drugs without changing diet and exercise risk rapid weight gain as appetite returns and muscle mass is lost
A Birmingham nutritionist says rapid weight regain after weight-loss injections is something she expected to see — and says it’s linked to muscle loss and a lack of lifestyle change while on the medication.
Sarah Hanratty says research now backing this up isn’t surprising, particularly for people who stop the injections without changing how they eat or exercise.
“Yeah, we did expect it,” she said. “And it’s not surprising that the research is showing that around two-thirds of the weight loss can be regained within 12 to 18 months of stopping if you haven’t changed your diet and lifestyle within that time.”
She explains that quick weight loss often leads to a loss of lean muscle mass, which plays a key role in keeping the metabolism working efficiently.
“When you lose weight quickly, you lose a lot of lean muscle mass — and that’s metabolically active tissue,” she said. “So when you lose that, it lowers your resting metabolic rate, which means your body’s ready to gain weight once appetite and food noise comes back.”
Hanratty says protecting muscle mass should begin while people are still taking the injections, not just after they stop.
“It really needs to start before transitioning off the injections — preferably during the entire time that you’re on them,” she said. “You need to protect your muscle mass. So that involves exercise, but also a protein-dense and nutrient-rich diet.”
She says those changes help regulate appetite and blood sugar, making weight maintenance easier once medication ends.
“If you have that in place, when you transition off the injections, you’ll find keeping the weight off much easier,” she said.
Hanratty says she’s worked with clients who’ve seen significant changes once they come off GLP-1 injections, particularly when appetite returns.
“When food noise returns and appetite increases, it can be hard to keep the weight at the same level,” she said.
She adds that long-term success depends less on the medication itself, and more on whether people rebuild their metabolic health.
“It will be the biggest predictor as to whether or not they’re able to keep the weight off over the longer term,” she said. “We work on actively rebuilding metabolic health and improving diet quality to help people maintain the losses they’ve had on their GLP-1 injections.”