In the 1975 movie "Pumping Iron," Arnold Schwarzenegger declared, "Milk is for babies." Although he actually did use dairy in his regimen when he was young (he’s 80% vegan now), he was right on about milk, according to a study in the Journal of Nutrition.

When researchers looked at the muscle-building benefits of whole milk versus skim milk (7.6 grams protein vs. 7 grams protein in 8 ounces, respectively) for women around age 69, they found that neither helped increase protein synthesis in muscles.

However, they stumbled upon evidence that walking did. 

The researchers started with the assumption that drinking milk twice a day would boost muscle protein synthesis and beef up muscle strength that tends to fade with age. But they ended up admitting that neither whole nor skim helped protect or build muscle.

By contrast, they found that when participants' daily walking habit was increased by 150%, that revved up protein synthesis in muscles and conveyed strength-building benefits.

If you're getting only 2,500 steps most days, increasing to around 6,200 daily will help fight age-related (and sedentary-related) loss of muscle. And when that becomes your daily bottom line, boosting that another 150% will get you up over 9,000 steps.

And for maximum muscle protection, do strength training two to three times weekly. I favor exercises that use your own body weight, such as squats, planks, and jumping jacks.

Then no matter how weak you may have been when you started your new walking/training routine, you'll be able to declare: "I'll be back!"