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MONTREAL — That morning yogurt might be more important than you think. Researchers have found that spreading your protein intake across breakfast, lunch, and dinner could help maintain muscle strength as you grow older.
Many people load up on protein at dinner – a chicken breast, steak, or fish fillet – while skimping at breakfast and lunch. According to a study published in The American Journal of Clinical Nutrition, this common eating pattern might be working against us, especially as we age.
The Protein Distribution Discovery
Researchers from McGill University and several other Canadian institutions discovered that seniors who distributed their protein intake more evenly throughout daily meals maintained better muscle strength compared to those who consumed most of their protein in a single meal – regardless of their total protein consumption.
The Quebec longitudinal study on Nutrition as a Determinant of Successful Aging (NuAge) tracked over 1,700 Canadian seniors for three years, measuring their physical abilities and dietary habits. Physical tests included grip strength, arm and leg strength measurements, timed walking tests, and chair stands.
For many participants, dinner typically contained the highest protein content, with breakfast having the least. Those who bucked this trend by consuming more balanced protein amounts across all meals showed significantly higher levels of muscle strength.
What Does ‘Even Distribution’ Actually Look Like?
Very few participants reached the often-recommended 30 grams of protein per meal threshold. Even in the group with the most balanced intake, women averaged about 18 grams at breakfast, 23 grams at lunch, and 23 grams at dinner, while men consumed roughly 21 grams at breakfast, 29 grams at lunch, and 30 grams at dinner.
By comparison, those with the most uneven distribution might have as little as 8 grams at breakfast (think toast with butter), 21 grams at lunch (a small sandwich), and 30 grams at dinner (a moderate portion of meat) for women. Men with unbalanced intake consumed approximately 11 grams, 20 grams, and 41 grams respectively.
Gender Differences and Aging Effects
Researchers found gender differences in how protein distribution affected physical function. While muscle strength benefits remained significant after accounting for various factors in both men and women, mobility benefits (like walking speed and chair-stand performance) were only initially seen in men, and disappeared after adjusting for other health factors.
Despite the connection between balanced protein intake and muscle strength, the study found that the rate of physical decline over three years wasn’t affected by protein distribution. Everyone’s strength decreased over time, with age emerging as the strongest predictor of decline.
Physical performance worsened noticeably during the study period, with muscle strength diminishing more dramatically than mobility. Men experienced a 20% drop in muscle strength and 6.5% decline in mobility, while women showed an 18.2% reduction in strength versus a 7.8% decrease in mobility.
What This Means for Your Plate
Of course, preserving muscle strength into old age helps prevent falls, supports mobility, and maintains quality of life. Research also shows that muscle strength in our later years is key to a stronger and sharper mind.
The findings point to a straightforward adjustment to eating habits that could yield substantial benefits. Rather than saving protein for dinner, incorporating more protein-rich foods at breakfast (eggs, Greek yogurt) and lunch (tuna, chicken, beans) might help maintain muscle strength longer.
For aging adults, this research highlights something nutritionists have long suspected: when you eat matters just as much as what you eat.
Paper Summary
Methodology
The NuAge study followed 1,741 participants (827 men and 914 women) aged 67-84 for three years. Researchers measured physical performance annually using two composite scores: muscle strength (handgrip, arm, and leg strength) and mobility (timed-up-and-go, chair stand, and walking speed). Dietary information came from six 24-hour food recalls (three at baseline and three at year 2). Protein distribution was calculated using the coefficient of variation (CV), with lower values indicating more evenly distributed protein intake. Researchers used mixed model analysis to examine how physical function changed over time in relation to protein distribution, controlling for factors including total protein intake, BMI, cognitive status, depression, smoking, muscle mass, education level, and disease burden.
Results
People with more evenly distributed protein intake showed higher muscle strength throughout the study period, independent of total protein quantity. This relationship remained significant in both men and women after adjusting for covariates. For mobility, men initially showed better scores with evenly distributed protein, but this connection disappeared after adjustment for other factors. While protein distribution was linked to higher baseline strength, it did not affect how quickly physical function declined over three years.
Limitations
The study followed relatively healthy, independent older adults for only three years, which may not be long enough to detect how protein distribution affects physical function decline rates. Additionally, factors not controlled for in the study, such as hormone replacement therapy and falls, may have influenced changes in physical function. As an observational study, causal relationships cannot be definitively established.
Publication Information
The study, “Even mealtime distribution of protein intake is associated with greater muscle strength, but not with 3-y physical function decline, in free-living older adults: the Quebec longitudinal study on Nutrition as a Determinant of Successful Aging (NuAge study),” was published in the American Journal of Clinical Nutrition in 2017 (106:113–24). Authors included Samaneh Farsijani, Hélène Payette, José A. Morais, Bryna Shatenstein, Pierrette Gaudreau, and Stephanie Chevalier. The study was supported by a grant from the Dairy Farmers of Canada.
Note: This article is an updated version of a post first published on January 23, 2018.
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