How to lose fat and gain muscle at the same time

For many people, the number on the scale looms large in their mind, becoming a focal point in their journey to better their health. If it goes down, they’re doing things right. If it stays the same or goes up, they’re failing. But what they may not realize is that all the scale measures is your weight, the total mass of everything on your body. Sometimes losing weight isn’t the right goal, but body recomposition is. 

That’s because with body recomposition — a fancy way of saying losing fat and gaining muscle — the number on the scale might stay the same or barely budge, but your body could still be reaping some serious benefits. Read on to learn about how body recomposition could boost your health and help make you feel better in your body, and how it may set you up for healthier aging down the line. 

Key takeaways

• Body recomposition refers to simultaneously losing body fat while gaining muscle mass.

• Strength training and eating a balanced, protein-rich diet are vital parts of the process as they help you build more muscle.

• Body recomposition takes time and may be more challenging for people already close to their ideal body fat.

Your overall body weight is made up of lots of things: water, bone, organs, ligaments, muscle (a.k.a. lean mass), fat, and more. And while you can’t change a lot of those things — your organs are your organs — you can change how much fat and muscle you have. And doing that is what body recomposition is all about.

“The general concept of body recomposition is shifting your percentages of body fat and lean mass,” says Mark Kovacs, Ph.D., exercise physiologist and CEO of the Kovacs Institute. And that means reducing your body fat and increasing your muscle mass.

And while gaining muscle and losing fat can make you look leaner, the benefits run deeper than that. “It has direct carryover to health, quality of life, and functionality, as well as aspects related to staying independent as we get older,” says Abbie Smith-Ryan, Ph.D., CSCS*D, a professor of exercise physiology at the University of North Carolina at Chapel Hill.

For instance, your metabolic health might enjoy a particular boon: According to a 2021 study in the Journal of Clinical Medicine of nearly 200,000 people, those who increased their proportion of lean muscle by just 1% had 19-21% lower odds of developing metabolic syndrome at the two-year follow-up; people whose relative fat increased by the same amount, on the other hand, had up to 25% higher odds of developing that condition.

Focusing on body recomposition is different from focusing on weight loss. With weight loss, you don’t really differentiate between what kind of weight you’re losing — so it’s common to lose muscle along with fat as you chase a lower number on the scale. But with body recomposition, the scale might not move very much at all, since you’re gaining muscle mass as you’re losing fat. For instance, if you lose three pounds of fat and replace it with three pounds of muscle, the scale will spit out the same number even though the makeup of your body is different.

A regular scale doesn’t tell the story for body recomposition, but there are analog ways to check on your progress. These include snapping a pic every week and seeing how your body changes, measuring your waist and hips, or even noticing how the same pair of pants fit as the weeks and months go by. That’s because as you lose fat and gain muscle, you might drop inches around areas like your belly, thighs, or glutes. Muscle is denser than fat, so it takes up less room.

There are higher-tech options too, like the Weight Watchers AI Body Scanner. Use your phone’s camera to take a quick body scan and you’ll quickly see your percentage of body fat and lean muscle mass as well as your waist circumference. Do the scan monthly to see how it changes over time.

Body recomposition is certainly possible — but how easy or difficult it is depends on a bunch of different factors, says Jean Fry, Ph.D., R.D., director of the Nutrition Translational Research and Intervention Laboratory at the University of Kentucky. She has observed lots of people successfully losing fat while gaining muscle in the studies she’s conducted, and in many cases, those who saw the biggest changes were those with more weight to lose. They tend to be at a higher body fat percentage to begin with and start sweeping dietary changes and resistance training at the same time, she says.

The process may be slower and more subtle for those who are leaner or have already been doing resistance training. “It's just a lot harder once you're already in good shape and already have established habits that have allowed you to be pretty close to your goals,” she says. “The changes just are less dramatic.”

Lifestyle and nutritional factors also play a huge role, too. Not strength training consistently can make body recomposition more difficult, as can skipping meals and skimping on protein, says Kelly Jones, M.S., R.D., C.S.S.D., a board-certified sports dietitian. All of these factors can hamper your ability to build muscle.

If you want to change your body composition, there’s not just one step: Successfully losing fat while gaining muscle involves a combination of factors — in and out of the gym. 

1. Do progressive resistance training 

When you’re eating less calories, your body has less energy to build muscle. Consistent strength training is at the foundation of body recomposition, since it will build that muscle. Do it for 30 to 60 minutes, at least twice a week, says Kovacs. “One session is better than nothing, but two brings significantly more benefits than one, and three is better than two," he says. 

Consider making your workouts full-body sessions, choosing exercises that work big muscles across multiple muscle groups, like squats or rows. “You get the best benefit for the shortest amount of time,” Kovacs says.

The good news is that you’re going to get stronger. And this means that you need to do what’s called “progressive overload,” or continuing to challenge your muscles as the weeks go by. You might increase your reps or bump up the weight. To make sure you’re working hard enough, think about your “reps in reserve,” says Kovacs. If you’re doing 10 reps but could easily bang out twice that much, the weight is too light. You want to keep two to four reps in reserve, meaning for your 10-rep set, maybe you could eke out 12 to 14 reps at that weight if you pushed to absolute failure.

After your workouts, make sure you give your muscles enough rest, so they can recover and continue to grow stronger. Leaving at least one full day between sessions is a good rule of thumb to make sure you’re not overworking them.

2. Prioritize protein 

Resistance training places mechanical tension on muscle fibers — i.e. tiny, microscopic tears. This signals the body to increase muscle protein synthesis to repair the damage. Protein provides the amino acids needed to do that, building strength and muscle. 

As for how much protein you need? Taking in 1.2 to 1.6 grams of protein per kilogram of bodyweight can help maintain or build muscle in both young and older adults, per a 2022 review. But there may also be benefits to going even higher, particularly if you’re especially focused on building more muscle. Jones recommends at least 2.0 grams of protein per kilogram of bodyweight each day during your recomposition phase. That means a 150-pound person would aim for about 136 grams of protein. That can be a lot, so try to spread it out throughout the day, Jones says.

3. Eat enough food 

You only need to be in a mild caloric deficit if your goal is body recomposition, though some people may be able to gain muscle while losing fat without cutting any calories when they shift their physical activity focus to strength training, says Jones. If you find that you do need to reduce calorie intake to lose fat, keep it modest — not dramatic — by cutting about 250 calories per day, she says. You can make it easier on yourself by using Weight Watchers — the Points^® system ensures you are eating enough of the good stuff every day while still helping you lose fat.

What you don’t want to do is crash diet. If you try a huge calorie cut — like trimming 1,000 or so a day — your body won’t be able to build the muscle you’re looking for. And there are other side effects, too: “Severe cuts affect your ability to think, your ability to do your job, and definitely your ability to do any workouts you have planned,” says Fry.  

Don’t forget sleep, recovery, and consistency

Adequate sleep plays an important role in the recovery process. “Getting that eight hours or so of sleep is where we get a lot of the muscle growth and repair that occurs,” says Kovacs.

It will also help you feel fresh during your workouts, allowing you to expend maximum effort during your sets and making it less likely you skip out on a session. Sleep and recovery promotes the consistency that’s vital for reaching your ultimate body recomposition goals, since losing fat and gaining muscle takes time. 

“The overall foundation of a healthy diet that supports healthy weight loss is also good for body recomposition,” says Fry. Think: whole grains, lots of fiber-rich fruits and veggies, and enough protein throughout the day to help your muscles grow, repair, and recover.

Despite what “recomp diet” plans you may see touted online, eating to build muscle while losing fat doesn’t need to be bland or boring, says Jones. You don’t want to eat the same old stuff every day, since variety is vital for packing your diet with antioxidants and micronutrients — and for making your nutrition sustainable. “If it’s just grilled chicken, rice, and broccoli every day, you’re going to have cravings for more indulgent foods,” says Jones. 

Instead, she says, focus on a checklist for your meals, ensuring you’re hitting the following with each one:

• Lean protein

• Fiber-rich carb

• Vegetable

With over 12k recipes, the WW app can help you stave off meal boredom while still hitting all the right nutrients for body recomposition.

Body recomposition takes time, and patience is key — it’s not something you’ll see in a few weeks’ time. “Three months is a framework we want to work within,” says Kovacs. Now, this doesn’t mean your ultimate goal will be achieved in three months. But that’s enough time that you should be able to start seeing improvements, which you can then build upon as you continue.

You want to eat more protein, strength train more regularly, and take in the right amount of food to gain muscle and lose fat — but how do you do that without feeling overwhelmed? 

Weight Watchers makes it simple. In addition to the tailored-to-you Points system and AI Body Scanner, the WW app lets you track your food and activity, showing you how close you are to hitting your protein and exercise goals. The program also gives you access to plenty of inspo and accountability with a seemingly endless library of recipes, live or on-demand workouts, and connection with members and Coaches on a similar journey.

Body recomposition means gaining muscle while losing fat at the same time. The key is strength training regularly, eating plenty of protein, and giving your body time to recover. Since a scale won’t tell the whole story, you can track your progress to give you better insights using Weight Watchers AI Body Scanner, measuring your waist and hips, or taking photos along the way. Just remember: Changing your body composition takes time. While someone who’s new to exercise or has more body fat to lose might see results quicker, more significant body recomposition won’t be obvious for months. That’s why consistency is so important — something that can be made easier by tracking your daily habits in the Weight Watchers app.