weight loss · Feb 18, 2025

How to Lose Weight and Gain Muscle Simultaneously

older woman in workout attire sitting on a yoga mat and drinking water before exercising

By Sarah Jayawardene, MS

When you set out to lose weight, what you’re likely trying to do is lose fat. During weight loss, especially when taking GLP-1 agonists like Ozempic or consuming a very low-calorie diet, you will likely lose both fat and muscle. This can reduce strength, slow metabolism, and make it more challenging to achieve a leaner, healthier body.

Maintaining muscle through your weight loss journey is crucial for overall health, as muscle is integral to your metabolism and supports physical function, especially as you age. Fortunately, it is possible to lose fat while preserving or even increasing muscle mass. Research shows that this process, called body recomposition, can be achieved through consistent strength training, a diet with adequate protein and a moderate calorie deficit, and enough sleep to aid recovery and hormonal regulation. Even if your weight doesn’t dramatically drop (since muscle is more dense than fat), reshaping your body and metabolism will pay off for your long-term health.

Why You're Losing Both Muscle Mass and Fat

When trying to lose weight, your body doesn’t have a “fat-only” switch — it responds to energy demands, pulling from whatever’s available to keep you going. Your body will first prioritize using carbohydrates from your food (in your bloodstream), then stored carbohydrates (in the form of glycogen in your muscles and liver), then start to shift and tap into fat stores. It’s important to note that these processes are not mutually exclusive, meaning they can happen at the same time, and that not all tissues in your body can use fat for energy. Restricting your calories or taking medications that suppress appetite (like Ozempic) can trigger the body to lose muscle and water weight, alongside fat.

Fat loss itself is a complex process influenced by various factors, including your hormones (e.g., insulin and cortisol), genetics, and lifestyle choices. The main driver of fat loss is a caloric deficit (eating fewer calories than your body uses) [1]. However, when you are in an extreme caloric deficit or when you drop your calorie intake too quickly, your body not only burns fat but can also start to break down muscle tissue. This can lead to muscle loss as your body scrambles for energy, tapping into protein stores when fat and carbs run low. However, depending on your approach, losing fat while keeping — or even gaining — muscle is possible (more on this below).

Ozempic and muscle loss

If you’re using Ozempic to lose weight, you might notice more than just fast fat loss — muscle mass can decrease rapidly as well. GLP-1 agonists like Ozempic work by slowing digestion and increasing feelings of satiety (reducing appetite and feelings of hunger). While studies show the effects of Ozempic lead to an approximately 15% decrease in overall body weight, research suggests that anywhere from 15-60% of that weight loss is actually your body losing muscle [2, 3].

Ozempic’s appetite suppression can result in an extreme calorie deficit; when your daily calorie intake drops significantly and quickly, your body pulls from muscle mass to start breaking down protein for energy. This is especially true if you’re not consuming protein-rich meals and meeting daily requirements for protein intake. Additionally, being in a calorie deficit can make you feel more lethargic and fatigued. You may feel less motivated to go to the gym or move around, leading to increased sedentary behaviors that further tip the scales toward muscle loss.

The takeaway: Without resistance training to signal your body to keep muscle or a diet rich in protein to rebuild muscle, Ozempic will cause you to lose muscle along with fat.

Why Muscle Mass Is Critical for Fat Loss

While losing weight might feel like a win, regardless if the weight is coming from fat or muscle, losing too much muscle in the process can harm your metabolism and your long-term health goals.

Muscle is your body’s calorie-burning engine: it elevates your resting metabolic rate, meaning you burn more calories even when you’re relaxing or inactive. Simply put, having more muscle boosts your metabolism [4].

When your muscle mass decreases from overly aggressive weight loss, you’re left with a slow metabolism, making it tougher to keep fat off long-term [4].

In other words, protecting and building muscle isn’t only about your strength — it’s a smarter and more sustainable way to lose fat and maintain a healthy weight.

Additionally, as you age, the importance of maintaining muscle becomes even more crucial. Muscle mass naturally declines as you get older, especially after age 40 or post-menopause. This leads to an increased risk of sarcopenia, i.e., age-related involuntary muscle loss that can make it harder to walk, maintain stamina, keep your balance, and enjoy day-to-day activities [5]. Building healthy fitness and diet habits now can combat the development of sarcopenia as you grow older.

Beyond your metabolism and strength, muscle shapes how you look and feel by improving your body composition, which is the proportion of fat mass to muscle mass in your body. More muscle means a leaner, more toned appearance, even if the scale doesn’t drop as much (since muscle is denser than fat).

Can You Lose Weight and Gain Muscle at the Same Time?

In short, yes, you can lose weight and gain muscle. However, it's more important to reframe the question. Instead of focusing on losing weight and gaining muscle, it's more important to focus on losing fat and gaining muscle.

The scale might not always reflect a big drop in weight since muscle weighs more than fat, but your body will transform, looking leaner, stronger, and more toned. Besides the way your body looks, losing fat while gaining muscle is the cornerstone of sustainable, long-term weight management and overall health.

Research shows with the right approach, body recomposition is achievable and comes down to three key pillars:

Strength training: Increases muscle mass and decreases fat mass, even when in a slight caloric deficit.
Nutrition: High protein intake and balanced macronutrients to fuel your body.
Sleep: Essential for hormone regulation, muscle recovery, and fat loss.
Supplementation: In tandem with lifestyle changes, consider taking products like Motus to boost fat loss efforts.

4 Strategies to Lose Fat and Gain Muscle

1. Resistance training

To build muscle and boost fat loss, resistance training is key. Strength and resistance training is backed by science to reshape your body, even in a caloric deficit.

Frequency: Hit the gym or do an at-home workout 3-4 times a week.
Focus: Major muscle groups should be trained at least twice a week to maximize muscle growth [6]. Target large areas like legs, back, and chest.
Type: Prioritize compound movements – think squats, deadlifts, and bench presses – to engage multiple muscles at once and maximize efficiency [6, 7].
Volume: Aim for 3-4 sets per exercise with 6-12 reps. Research suggests this volume is the sweet spot for hypertrophy (muscle growth) [7].
Progression: Gradually increase weight or resistance. Keep challenging yourself by slowly increasing weight or resistance as your strength builds [6, 7].

2. Eat protein and balance your macronutrients

Nutrition is your fuel for body recomposition. A balanced and healthy diet not only helps you lose fat while maintaining or increasing muscle mass, but also lends to balanced hormones and blood sugar levels. While protein is the star when talking about muscle growth, carbohydrates and fats also play an important role – as does meal timing and calorie intake.

Protein intake: Aim to consume 1.6-2.4 grams of protein per kilogram of body weight every day, which translates to approximately 0.75-1.1 grams of protein per pound of body weight (this would be 112-168g protein per day for a person weighing 70kg or 154lbs). Research shows this range is ideal for muscle growth and maintenance, even in a caloric deficit [8, 9].
Caloric deficit: A modest decrease of approximately 500 calories daily can lead to fat loss without starving your muscles. You can get an individualized calculation for a calorie deficit using this quick Body Weight Planner Tool [10]. Once you know a target range for your daily calorie intake, using a calorie-tracking app can help keep you on course.
Balanced macronutrients: In addition to eating enough protein, focus on low-GI carbs and healthy fats, and avoid refined sugars. These will allow you to stabilize blood sugar and curb hunger [11].

Low-GI carbs include sweet potatoes and oats.
Healthy fats include avocado, fish, and nuts.

Meal timing: Consume protein before and after workouts to help with endurance and muscle repair.

Try a protein-rich snack like Greek yogurt 30-60 minutes before training to boost performance.
Eat a post-workout meal with 20-30g of protein (think chicken or whey protein) to speed recovery and muscle growth.

3. Get plenty of sleep

Sleep isn’t a luxury — it’s a non-negotiable when trying to build muscle and lose fat. If you're training and eating a balanced diet, but depriving yourself of sleep, you're limiting your ability to achieve your fat loss goals.

Your body does most of its muscle repair and growth during deep sleep, releasing growth hormone to rebuild what you broke down throughout the day [12]. This is especially important when you add strength and resistance training into your routine, as your muscles need time to recover.

Poor sleep can also impact hormones directly related to fat gain. Not getting enough sleep at night can increase levels of cortisol, a stress hormone that signals your body to break down muscle and store more fat. Adequate sleep keeps cortisol lower and additionally helps to balance hormones that regulate your appetite, like leptin and ghrelin. In other words, poor sleep can make you hungrier and lead your body to hold onto fat.

Aim for 7-9 hours of sleep per night to stay on track. Research has shown that sleeping for less than 6 hours per night leads to more fat gain and less fat loss, even with the same calorie intake [13].

4. Consider supplementation

In addition to diet, exercise, and sleep, supplementation can be key to a long-term, sustainable strategy for losing fat and building muscle. Well-designed supplements, like Motus, can work in tandem with healthy lifestyle changes to promote a better metabolism and toned body.

Motus specifically targets fat loss with natural ingredients like Berbevis®, Siliphos®, alpha lipoic acid, taurine, and nicotinamide. In research on mice, Motus has been shown to lead to significant fat loss (25%) with no associated muscle loss.

fat change vs. lean muscle mass change with placebo, glp-1, and motus

Takeaways

Losing weight isn’t just about the number on the scale. Gaining muscle while losing fat is a sustainable approach to health that empowers you with control over your physical form and metabolism.

Muscle mass is critical for your health — it increases resting metabolic rate and supports physical resilience as you age.
Balance is everything — a moderate caloric deficit paired with smart strategies can help you keep the muscle while trimming the fat.
Prioritize strength exercises, protein-rich meals, and sleep — small adjustments can make a big difference in holding onto your muscle while still losing fat.

References

Sarah Jayawardene obtained her Master’s degree in Biochemical and Molecular Nutrition at Tufts University. She has a deep passion for nutrition science and health communication, with expertise in metabolism and metabolic diseases. As a supporter of integrative and functional medicine, Sarah strives to provide her readers with science-backed information that lends to improved health and wellness.