Building Muscle After Age 40: The One Thing You Need to Do Now

The most efficient way to maintain a fast metabolism and stay slim when you're over 40 is to build lean muscle mass. But your efforts can get stuck in a rut when you're not sure how to train or how much chicken breast you should dig into post-workout. To clear up some of the confusion, university researchers published a comprehensive study in the British Journal of Sports Medicine that answers age-old questions about whether protein and weight training are as effective as they're often touted.

Researchers reviewed past studies that included a total of 1,863 men and women of a variety of ages and fitness levels and discovered that, indeed, people who ate more protein and weight trained gained stronger and larger muscles—especially as they grew older. And folks who upped their protein intake increased their strength by about 10 percent and their muscle mass by 25 percent compared to the control groups.

So what's the Goldilocks zone for your daily protein intake? Despite the FDA's low 50-grams-per-2,000-calories recommendation per day, the researchers confirm that 1.6 grams of protein per kilogram (or 2.2 pounds) of body weight is ideal. So if you're a woman who weighs 150 pounds, you should consume about 109 grams of protein, according to this study.

"We think that, for the purposes of maximizing muscular strength and mass with resistance training, most people need more protein," doctoral student and study leader Rob Morton said, according to The New York Times, adding that this holds especially true for middle-aged and elderly weight trainers who were shown to miss out on the most protein in the reviewed studies.

What's more: Going above the 1.6 grams of protein per kilogram recommendation didn't result in gaining more muscle. And any type of protein source—from plant-based to animal-based, and powders and whole foods—all proved to be effective in building lean muscle. In what was arguably the most shocking result of the analysis, researchers also discovered that consuming protein at any time of the day produced similar gains when compared to downing protein right after hitting the weight rack.

Now that you're inspired to book a fitness class and down some lean meat, discover our 40 Healthiest Foods If You're Over 40 to make over your diet.