Why distributing protein over three meals may keep muscles strong as we age

Leslie Beck, a Toronto-based private practice dietitian, is Director of Food and Nutrition at Medcan.

It's not news that protein is important for muscle mass. Protein-packed foods provide amino acids, the building blocks of muscle tissue.

What is news, though, is that how you distribute your protein intake over the day may impact your ability to maintain muscle strength as you age.

According to researchers from McGill University in Montreal, older adults who spread their protein evenly over three meals had greater muscle strength than their peers who skewed their protein intake to later in the day.

For the study, the researchers followed 1,741 independent living healthy adults, aged 67 to 84, for three years. Muscle strength and mobility was measured yearly and food intake was analyzed at the beginning of the study and again two years later.

Even protein at meals, regardless of quantity, matters

The findings, published earlier this summer in the American Journal of Clinical Nutrition, revealed that study participants lost muscle mass and strength at the same rate over the three-year period.

However, those who spread their protein evenly over the day had higher muscle-strength scores throughout the entire study. That was true regardless of how much protein participants consumed.

In other words, it seems that whether you eat 60 grams or 90 g of protein each day, when it comes to muscle strength, you're better off balancing it over breakfast, lunch and dinner.

It makes sense to evenly space out your protein intake, since there's a limit to the rate at which amino acids can by synthesized into muscle tissue.

Women who ate protein evenly across meals consumed, on average, 20 g each at breakfast, lunch and dinner; men ate about 30 g a meal.

Conversely, participants who had lower muscle-strength scores throughout the study ate a small amount of protein at breakfast (8 to 11 g), a little more at lunch and the majority at dinner.

The findings have important implications for maintaining muscle health as we age.

Age-related muscle loss, called sarcopenia, can begin as early as your 30s, with up to 50 per cent of muscle lost by the age of 70. Entering middle age with good muscle mass and strength can help prevent frailty later on.

In older adults, declines in muscle strength and function can impact daily activities such as getting up from a chair, walking quickly across the street and lifting a grocery bag.

Sarcopenia also predisposes older adults to falls and bone fractures.

How much protein?

Sedentary adults are advised to consume 0.8 g of protein for every kg of body weight a day, which, for instance, is 55 g for a 68 kg (150 lb.) woman. If you work out regularly, you need 1.2 to 2 g a kg per day depending on your sport.

The official daily recommended protein intake of 0.8 g/kg isn't enough for older adults to maintain muscle, though.

Healthy adults over 65 should consume 1.2 g of protein a kg per day. For an 82 kg (180 lb.) male, that translates into 98 g of protein, roughly 30 g a meal.

Older adults who are undernourished or have an illness will benefit from consuming more protein, 1.2 to 1.5 g a kg per day.

Consider protein at breakfast

Many of us do a good job of including protein at lunch and dinner.

For example, four ounces of cooked chicken has 35 g of protein, 1 can (120 g) of tuna has 32 g and one cup of firm tofu has 22 g. Eating one-half cup of Greek yogurt for dessert adds 12 g protein.

It's the morning meal where many people come up short.

To get 20 to 30 g of protein, include a few protein-rich foods in your breakfast. One egg (or two egg whites) + one cup of soy milk (or cow's milk) + one-quarter cup of almonds delivers 22 g of protein.

Or, add a scoop of protein powder (20 to 30 g) to oatmeal or a fruit smoothie.

Stay active

Physical activity, especially resistance exercise, is also crucial for maintaining muscle mass and strength as you age. Being less active when you're older is a contributing factor to sarcopenia.

It's never too late to regain some muscle and maintain it by combining resistance training with an adequate protein intake.

Protein by the numbers (grams)