My favorite session at the 2017 Academy of Nutrition and Dietetics Food and Nutrition Conference was presented by physiologist and researcher Dr. Luc Van Loon of Maastricht University Medical Centre in the Netherlands. (And by the way, the moderator who introduced him was Roberta Anding – the sports dietitian for the Houston Astros.)
“Take a look at your arm,” Van Loon began. “Your muscle tissues are constantly breaking down and building up. In fact, every 2 to 3 months, you have a new arm … and other muscles throughout your body.”
Muscles can change, he explained. Throughout life, we can either condition our muscles to grow or decondition them. In other words, if we’re not synthesizing muscle, we’re losing it.
What stimulates our muscles to grow? Food (especially protein) and physical activity. Protein not only provides the building material (amino acids) for new muscle; it also signals the body to get busy and start making muscle.
In fact, 3 to 4 hours after eating, protein from your meal is now you, says Van Loon. “You are what you just ate.”
How much protein converts to muscle depends on several factors, including the source. Whey protein derived from milk, for example, stimulates a higher rate of muscle growth than casein, another milk protein. And research shows that protein from animal sources generally has a bigger muscle-building response than plant proteins. No worries, though. Vegetarians can easily compensate by eating more of a wide variety of plant proteins, including soy, beans, grains and nuts, to get the best mix of muscle-building amino acids.
For most of us, about 20 grams of protein (the amount in 3 ounces of meat, poultry or fish) at every meal is enough to maximize muscle synthesis after meals. Older folks and athletes may need more.
Timing is important, as well. Studies have found that three protein-containing meals a day stimulate more muscle building than just one or two protein meals a day.
And this was interesting. “Chewing has a huge effect on anabolic response (the ability of the body to make muscle from protein),” our speaker reported. Well-chewed food, he explained, is better digested and available for building muscle.
We can’t just eat protein and expect to form strong muscles, however. If you become less active, you are less than what you just ate, says Van Loon. Exercise and food work together in the muscle-building process.
Physical activity, especially before we eat, increases our muscles’ ability to turn protein from our meal into muscle. “If you are physically active before you eat, you are more than what you just ate,” he told us.
Barbara Quinn is a registered dietitian and certified diabetes educator affiliated with Community Hospital of the Monterey Peninsula.