How to build strength if you’re on weight loss drugs

When it comes to weight loss, what works for some might not work for another. But one method that’s become a big talking point over the past year is GLP-1s, or weight-loss medications.

More people are using them, and naturally, lots of questions are coming up about how they fit alongside exercise, nutrition and long-term health.

When people lose weight quickly, muscle loss can happen alongside fat loss. That’s why strength training and eating enough nutrient-dense foods, including protein, play a pretty important role.

What’s the link between GLP-1 weight loss drugs and muscle loss?

Dr Marie Spreckley, a researcher in obesity and diet at the University of Cambridge, says when people lose weight – whether through medication, diet, or surgery – some loss of muscle mass is expected. This is because when calorie intake drops, the body starts using stored energy, burning both fat and some muscle to keep functioning.

Weight loss drugs primarily reduce appetite, which creates a calorie deficit leading to weight loss, says Marie. “However, without strategies to support muscle preservation, part of that weight loss can come from lean muscle mass,” she says.

This will happen in any weight loss method that involves drastic reductions in body weight, adds Professor Leigh Breen, an expert in muscle physiology and metabolism at the University of Leicester. “Being in an energy deficit means you’re not in a great scenario for maintaining and building muscle, as it needs energy and protein to grow,” he explains. That’s why muscle mass reduces while on these drugs.

How much muscle mass is reduced?

Muscle mass has been a low priority for studies in these areas so far, says Prof. Leigh. But, he says, estimates suggest some of the earliest GLP-1 drugs results showed that 25-30% of the weight lost on these drugs could be from muscle. In some of the later drug trials, that figure could be as high as 40-45%, he adds.

Some have questioned the importance of this muscle mass. Of course, some people could afford to lose a bit of muscle without it affecting their life too much. But, he adds, “in certain populations like older adults – who already have low muscle mass – the muscle lost might drop so low they might not be able to carry shopping or rise from a chair, for example.”

These older adults – and others who are physically inactive or who have low baseline muscle mass – are more vulnerable to losing muscle during weight loss, adds Marie.

For long-term health and the maintenance of a healthy bodyweight, it’s “vital you hang on to as much muscle mass as possible,” says Dr Leigh.

“These medications are not licensed for life. They’re a catalyst for health change and should be prescribed alongside lifestyle behaviour change.”

How does strength training help?

“It’s fairly safe to say regular, structured resistance strength training will offset the vast majority of muscle mass lost,” says Prof. Leigh, “but research is still ongoing.”

This style of training is one of the most effective strategies to preserve muscle during weight loss, adds Marie. “Without this stimulus, the body has little reason to retain muscle during a calorie deficit,” she says.

Guidelines recommend that adults do muscle-strengthening activities involving the major muscle groups on at least two days per week, alongside other “moderate intensity” physical activity.

Why is protein important?

Protein provides the nutrients needed to maintain and repair muscle tissue.

When you’re eating reduced calories, the body’s natural tendency is to break down both fat and muscle. Ensuring enough protein can help offset this by helping the body actually build and repair muscle, says Marie.

This is particularly relevant for people using GLP-1 medications, she says, because appetite suppression can sometimes lead to lower overall food intake (including protein). Ensuring meals contain enough protein is important for maintaining muscle and recovering from exercise.

How can you get started with strength training?

If this is new to you, Prof. Leigh suggests following the chief medical officers’ guidelines: training the whole body twice a week. The more advanced your training gets, the greater the muscle retention benefit, he says.

If your strength training increases to 3-4 sessions a week, targeting the whole body, this will have added benefits, adds Leigh. Marie says training could include “bodyweight exercises, resistance bands, or weight training, focusing on the major muscle groups.”

“Focus on simple changes, like home workouts,” adds Leigh, “this can be achieved in a home setting or even a group class.”

For those who are strength training for the first time, you’ll likely notice improvements within a matter of weeks to your strength and muscle.

Beyond strength, adding in other positive lifestyle behaviour changes – like more walking, or increasing cardio fitness levels – is key for long-term maintenance of muscle. “The more you move, the better it is,” says Prof. Leigh. “And a lot of this can be done at home, you don’t need expensive gym memberships.”

Resources to help you build strength:

• Try this 10-minute Beginner Strength workout on The Body Coach TV
• Join our 4-week First Steps to Strength programme on The Body Coach app, aimed for complete beginners to build strength using resistance bands.
• Join The Body Coach app for a structured training programme – incorporating dumbbells and kettlebells – to build strength and improve cardiovascular fitness.

This article was written by The Body Coach content team.