How to Preserve Muscle During Weight Loss?

It is no secret that weight loss tops as one of the most common New Year's resolutions. And yet, one crucial consideration is often neglected: muscle retention. As we lose weight, some of it comes from muscle, not just fat.

While losing fat can positively contribute to one’s health, losing too much muscle will not. This is because low muscle mass is associated with various adverse health effects, including worsened blood sugar control, weakened bones, and increased blood pressure.

Fortunately, there are strategies you could follow to help you maintain your muscle mass during weight loss. In this article, I will outline the main expert recommendations and other practical tips to keep in mind.

What weight loss strategies are more susceptible to lean mass loss?

With novel weight loss drugs like Mounjaro and drugs used for weight loss like Ozempic (GLP-1 agonists), muscle retention is receiving more attention.

Current studies suggest that people using these obesity treatments may lose a higher proportion of lean muscle mass compared to traditional weight loss methods.

Multiple factors could be influencing this, but lower protein intake due to substantial appetite reduction and rapid weight loss are some of the caveats.

In other words, while highly effective, this new weight management strategy may also increase the risk of unintended lean mass loss if not properly managed.

Keep in mind that this does not apply solely to pharmaceutical weight loss, as traditional methods can have similar effects, especially if the following strategies are overlooked.

Protein matters

If you noticed more protein snacks popping up in grocery stores, you are not the only one. While some people hate the high-protein diet trend, protein can be especially beneficial for those who are trying to lose weight.

In fact, consuming an adequate amount of protein may help prevent lean mass loss on a caloric deficit.

The question is, how much protein do you actually need?

Most experts suggest getting between 1.6 and 2.2 g (~0.8–1.0 g/lb) of protein per kilogram of body weight, especially for those who are trying to lose weight.

This is for several reasons, not only muscle retention, reminds us Nicholas Mosakowski, Registered Dietitian and Licensed Dietitian Nutritionist. Protein has the potential to support satiety and slightly increase the caloric expenditure due to the thermic effect of food. In other words, consuming more protein may support your weight loss.

Can you get too much protein?

“You can overeat any macronutrient and gain weight,” says Megan Pfiffner, Certified Nutrition Specialist.

“The big concerns about too much protein are usually around chronic kidney disease, but there is not a lot of data supporting lower protein diets as positively saving the lives of those with CKD. It is nuanced for people with that condition and their nephrologist to weigh the pros and cons of how much protein they consume,” she explains.

In addition, high-protein diets may have negative effects indirectly. For instance, increasing protein intake can sometimes lead to an increase in saturated fat intake, which is associated with an increased risk of heart disease. This is particularly concerning when the protein sources are animal-based, such as whole-fat milk, beef, and pork.

In other words, consider opting for plant-based protein sources, such as soy products or legumes, or lower-fat meats like lean chicken.

Consider exercising

Exercising has always been a go-to tool in weight management, but it does more than just help you burn more calories.

Treat exercising as a signal that tells your body to preserve muscle mass.

“Muscle is a very expensive tissue to maintain, so when we eat fewer calories, our body makes decisions about where to spend resources. If you aren't sending any signals to your body that the muscle is important to maintain, then it will let more of it go,” explains Pfiffner.

This idea is also backed up by clinical research. For example, one study found that caloric restriction alone leads to significantly more lean body mass loss compared to caloric restriction combined with exercise.

Additionally, losing weight solely through a caloric deficit can lead to reductions in VO2max, an indicator of aerobic capacity. Adding exercise to your weight management plan can help to maintain (or even increase) your VO2max levels.

Go slow

Losing weight slowly helps reduce muscle loss.

As suggested by research, consuming 30–40% fewer calories than your body needs may reduce protein synthesis. This means that if you burn about 2,000 calories per day and consume between 1,200 and 1,400 calories, you risk experiencing more muscle loss.

Moderate calorie restriction, in contrast, was not associated with reduced protein synthesis. In fact, as the study suggests, it actually increases it.

“A slower trajectory toward long-term fat loss may not provide those quick dopamine hits that large losses do, but it consistently leads to better body composition changes and sustainability,” reassures Andrew Harkins, Senior Physical Therapist.

What else to keep in mind?

While a high protein intake, exercise, and a small to moderate caloric deficit are key strategies, other factors may also help prevent muscle loss.

Experts agree that sleep plays a crucial role in maintaining muscle mass and promoting overall metabolic health.

“As a general starting point, I recommend aiming for around eight hours per night, with some elite athletes benefiting from closer to nine hours. Even for individuals pursuing modest goals, consistently getting less than seven hours can undermine training, recovery, and results,” shares Harkins.

Additionally, not allowing your body to recover can negatively affect muscle retention, says Mosakowski. “You don't build or preserve muscle during your workouts, you do it during recovery,” he adds.

How to track your body composition changes?

A DEXA scan is the most reliable tool to assess body composition. However, for tracking changes, it would be unrealistic to rely on it. After all, to undergo a DEXA scan, you will need to schedule a visit to a medical facility; thus, it is not only expensive but also time-consuming.

Smart scales offer the convenience of tracking changes at home. While they are sometimes slightly off, especially compared to the gold standard of a DEXA scan, they usually can help spot improvements over time. In other words, while they can’t be relied on to determine overall body fat percentage, they can show trends and help you determine whether you are making progress.

This is especially true if you are aiming for so-called body recomposition, which involves losing fat and gaining muscle. If you are losing fat while simultaneously gaining muscle, overall weight may remain the same. Using a smart scale can help you see if you are gaining muscle/losing fat, as they measure more than just overall weight.

Bottom line

Some muscle loss can be expected during weight loss. By prioritizing protein intake, engaging in regular exercise, and approaching weight loss gradually, you can minimize this negative consequence.

These strategies also help with sustainability — after all, keeping the weight off is often considered harder than losing it.