Why You Might Be Losing Muscle Tone and How to Stop It

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A woman flexing.

You hit the gym (pretty) regularly. You eat clean (most of the time). But when you look in the mirror, you notice drooping skin and fat where you once saw firm upper arms and sleek thighs.

As dismaying as it is, shrinking muscles are more than a vanity issue. Diminished strength equals a decreased quality of life. Minus strength, everything is more difficult: Doing chores, going for walks—simply living life to its fullest becomes a challenge.

Though it doesn't command headlines the way osteoporosis does, a condition called sarcopenia causes muscle mass to slowly shrink with age—to the tune of about 1 percent per year after age 40, says Doug Paddon-Jones, PhD, a professor at the University of Texas Medical Branch at Galveston. And certain things you do (or don't do) in the kitchen, at the gym, or between the sheets can accelerate the process.

1. You're Back-Loading Your Protein

Imagine, for a minute, heading up a home construction project. How successful would you be if your building supplies arrived on the last day? 

When you start your day with high-carb choices like toast or a sugary breakfast cereal and cap it off with a huge serving of meat or plant protein at dinner, you're essentially waiting till the last minute to provide your body most of its key muscle-building materials.

In a small study published in The Journal of Nutrition, Paddon-Jones asked a group of participants to consume 90 grams of protein per day, split two different ways. When they ate 30 grams each for breakfast, lunch, and dinner, they showed a 25 percent greater increase in protein muscle synthesis—the first step toward repairing and building new muscle—than when their protein intake was skewed to later in the day (10 grams at breakfast, 15 at lunch, 65 for dinner).

Try replacing some of the carbs in your breakfast with Greek yogurt or eggs to help spread your protein more evenly throughout the day, suggests Paddon-Jones. 

No time to cook in the morning? Try one of these 7 Classic Breakfasts Turned Into Smoothies, instead. And plan to get some protein—say, 10 to 15 grams—within 30 to 60 minutes of your workouts to maximize their muscle-building power.

2. You're Passing Over the Produce Aisle

Protein reigns supreme as a muscle-building macronutrient. But protein-rich foods such as meat, fish, and cheese—along with refined grains and salt—create acids inside your body that can start to eat away at muscle over time, notes a review article on diet and sarcopenia in the journal Osteoporosis International.

Fortunately, Mother Nature has provided a cure, says study co-author Ambrish Mithal, MD, of Medanta Medicity in Gurgaon, India. 

Fruits and vegetables supply potassium and magnesium that buffer these acids and protect your muscle tissue. What's more, antioxidants in leafy greens and bright berries fight reactive oxygen species that can damage muscle fibers over time. Aim for at least 3 cups of vegetables and 2 cups of fruit per day, Mithal advises. (Start with these 26 in-season foods and tasty ways to eat them.)