Training Talk: What You Need to Know About Gaining Muscle, Losing Weight

A hot topic among exercisers and athletes is the best diet and exercises to be able to gain lean muscle mass while losing fat. Is it even possible?

Maintaining or changing body composition (losing fat, gaining muscle) is a balancing act – you need extra calories/building blocks to build muscle…but to lose weight, you need to cut calories, which can result in losing both fat and muscle mass for many. Maintaining that weight loss becomes a challenge because when you lose weight, your body is smaller and needs less calories, and if you lose muscle, your body will burn less calories (muscle is the most metabolically active tissue). This means you need to eat less (or exercise more, or both) once you lose the weight to maintain your weight loss. For athletes, eating less calories can be hard – in the peak of training, hunger may through the roof, and losing muscle during weight loss is exactly what exercisers and athletes DON’T want when they’re trying to reach peak performance.

Researchers at McMaster University wanted to look into gaining muscle while trying to lose weight, and in doing so, their findings are being called the “holy grail” of diet and exercise – their diet diet and exercise routine allowed their research participants to lose fat and gain muscle.

In their  recently published a paper titled “Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial” was published in the American Journal of Clinical Nutrition. Researchers looked at body composition changes in overweight young men who were put  through intensive exercise and diet for about a month.

Research study details

Diet: They took the participants (40 men) and cut their calories by ~40% (compared to their calculated NEED, not their usual diets), and half the men ate 1.2 grams of protein per kilogram of body weight per day (lower protein) and the other half ate a higher protein diet, with 2.4 grams of protein per kilogram of body weight per day. Just for reference, the recommended protein level is only 0.8 grams per kg of body weight, though athletes need more protein each day. 

The higher protein group ate about 35% protein, 15% fat, 50% carbs.

The lower protein group ate about 15% protein, 35% fat, 50% carbs.

The difference in protein and fat came from the milk-based beverage each group drank several times per day, where the high protein group had a extra whey protein isolate added to their low fat dairy-based drink, while the lower protein group just had a high fat milk with no added protein. At least one beverage had to be consumed post-workout, so the higher protein group was also getting a larger post-workout protein dose.

Exercise: Both groups were VERY active – they participated in intense exercise sessions 6 days a week, including plyometric training, full body weight training, high intensity intervals…and on top of that, both groups walked at least 10,000 steps per day.


  • Both groups lost weight
  • Lean body mass (muscle) remained the same in the lower protein group (good!)
  • Lean body mass increased in the higher protein group (even better!)
  • Both groups lost fat mass (good)
  • The high protein group lost more fat mass (best!)

What this means

The combination of the intense exercise schedule and the extra protein (double and almost triple the normal recommended value) helped participants maintain, and even gain muscle mass even though they were cutting calories by 40%.

Both groups maintained carbohydrates, because of the “crucial role that fuel plays in performance,” according to researchers. By not cutting their carbohydrates so drastically, these participants were able to participate in difficult workouts throughout the session.

This research study is building off of many years of research that provide strategies for maintaining muscle mass during weight loss, but these strategies, including the McMaster University study are short-term and grueling – working out 6 days a week at a significant calorie deficit can be exhausting, and likely not sustainable for athletes or frequent exercisers.

For many athletes, cutting too many calories, especially calories from carbohydrates can result in low energy, poor performance and recovery issues.

To help your body retain muscle mass if you’re trying to lose weight, these two strategies in addition to increased exercise/a calorie deficit help maintain muscle mass:

Strength training helps your body build and retain muscle mass, which not only helps with body composition goals, but also makes athletes stronger all-around and more resistant to injuries. As far as the diet goes, this is one of the areas dietitians help clients with.

How much protein you need depends on your sport/exercises (The above study was doing a mix of high intensity intervals and strength workouts, but what about if you’re a runner? What about a strength training runner?) It also depends on your goal – what if you don’t necessarily want to LOSE weight, but you want to make sure you don’t lose muscle as you ramp up your training? A higher protein diet isn’t necessarily a very low carbohydrate diet – the diets that drastically cut carbohydrates from the diet may have athletes feeling tired and unable to complete their workouts as intensely as they would like, especially for endurance athletes.

Example: For a runner trying to get down to racing weight, focusing on getting 1.6-1.8 grams of protein per kilogram of body weight (body weight in lbs. divided by 2.2) will allow them to still get enough calories from carbohydrates to fuel their runs, while helping them maintain and build muscle mass as the season goes on. A 150 lb. runner would need ~110-123 grams of protein per day, spread throughout the day, including their post-workout meal or snack.

Find your balance: Make an appointment with the Sanford Sports Science Institute Nutritionist to make sure you’re eating in a way that supports your training goals by calling 605-312-7878!

In the mean time, check out this EatRight Article on Timing Your Nutrition!