When you get out to lose weight, you are probably aiming to lose body fat. As people set their fitness and weight-loss goals [1], they may envision shedding layers of fat and revealing lean muscle mass underneath. Turns out, losing weight is a little more complicated than that, especially if you have a lot of weight to lose.
"Any time you lose weight, you're going to lose approximately a quarter to a third in body mass, so you can't get around [losing muscle]," explained Eduardo Grunvald, MD, program director at UC San Diego's Weight Management Program [2]. But there are some ways to ensure you maintain and continue to build lean muscle, even as you continue to lose weight.
What to Eat
Protein is the building block of muscle and helps build and repair tissue, so it's imperative that you eat enough protein to gain muscle [4]. But how much is enough? Jim White, RD, ACSM, and owner of Jim White Fitness and Nutrition Studios, recommends 1.2 to 1.8 grams of protein per kilogram of body weight to build muscle. So if you weigh 180 pounds, that's about 81.6 kilograms, which means you should shoot for 98 to 147 grams of protein a day. To maintain muscle mass as you lose weight, Dr. Grunvald said that number can be much lower, about 15 percent of your overall daily calorie intake should come from protein.
Dr. Grunvald said to make sure this protein is coming from lean sources [5], such as fish, poultry, beans, and soy instead of steak, sausages, or bacon. In fact, Jim suggests eating clean, which means no (or very minimal) fried foods, added sugars, or alcohol.
Although most people focus on eating protein to maintain muscle mass, Jim suggests also eating a moderate amount carbs to increase energy and fuel workouts, about 40-50 percent of your daily calories.
How to Work Out
Cardio is usually the go-to form of exercise for people looking to lose weight, but strength training [6] is vital to maintaining and growing muscle. Jim said you should weight train two to three days a week to increase muscle mass. For weight loss, he said to shoot for 300 minutes of cardio over the course of one week.
Striking a balance between cardio and strength training [7] in your fitness routine will not only help you lose weight, but also help you maintain and even grow muscle mass.