Keeping muscle during weight loss should be just as an important a goal as burning fat.
However, people focusing on diet alone can lose anywhere from 20-30 percent of their weight loss from lean body mass, most of which is from muscle tissue (1).
While the scale may show the pounds dropping, this isn’t good news for body composition. Beyond looking good in the mirror, muscle quality and quantity is a major determinant of metabolic rate, exercise capacity, and healthy aging (2).
For the average person, muscle tissue makes up about around 40 to 50 percent of body mass (3). Yet muscle undergoes rapid turnover, meaning it’s constantly being built up or broken down. The rate of turnover depends on two very important variables which all of us have control over: exercise and nutrition.
Resistance exercise like lifting weights helps prevent the loss of muscle during an energy deficit by stimulating the cellular machinery in the cell that make proteins for muscle (3, 4). This process is muscle protein synthesis, or MPS. However, simply stimulating the machine to build muscle protein isn’t enough; there needs to be building material.
This is where dietary protein comes in – while it’s well known that consuming protein in combination with resistance training can increase lean body mass, it can also preserve muscle during weight loss (3). In fact, when in negative energy balance, the anabolic response to protein is enhanced (5). This increase in efficiency is an adaptive mechanism meant to preserve muscle during starvation (6). The body has also an increased need for protein in states of negative energy balance.
Whereas a modest reduction in energy can increase protein requirements, it’s even further increased with resistance exercise. But when significant weight loss occurs and energy is cut too drastically, muscle tends to be lost in much greater amounts (7). Coupling resistance training with increased protein intake during fat loss improves body composition, aids metabolism, and prevents decreases in performance.
Taking this a step further, dividing up protein intake equally over the day in the format of protein pacing can help the body absorb the protein more effectively. The research on protein pacing by nutrition and exercise researcher Paul Arciero clearly showed that performance measures improved with increased protein intake in both males and females (8, 9).
The bottom line is that if fat loss is your goal, include some form of resistance training like weightlifting or high-intensity interval training. Aim for a protein intake of 1.5 to 2.0 grams per kilogram per day divided over several meals containing at least 20 grams of high quality protein (10).
Lose the right type of weight during weight loss, which is fat, not muscle.