Most Americans eat a diet that consists of little to no
protein for breakfast, a bit of protein at lunch and an overabundance of
protein at dinner. As long as they get their recommended dietary allowance of
about 60 grams, it's all good, right?
Not according to new research from a team of scientists led
by muscle metabolism expert Doug Paddon-Jones of the University of Texas
Medical Branch at Galveston. This research shows that the typical cereal or
carbohydrate-dominated breakfast, a sandwich or salad at lunch and overly large
serving of meat/protein for dinner may not provide the best metabolic
environment to promote healthy aging and maintenance of muscle size and
strength.
The new study, now online in press in the Journal of
Nutrition, shows that the potential for muscle growth is less than optimal when
protein consumption is skewed toward the evening meal instead of being evenly
distributed throughout the day.
Age-related conditions such as osteoporosis (bone weakening)
and sarcopenia (muscle wasting) do not develop all of a sudden. Rather they are
insidious processes precipitated by suboptimal lifestyle practices, such as
diet and exercise, in early middle age, the study states.
The study's results were obtained by measuring muscle
protein synthesis rates in healthy adults who consumed two similar diets that
differed in protein distribution throughout the day. One of the diets contained
30 grams of protein at each meal, while the other contained 10 grams at
breakfast, 15 grams at lunch and 65 grams at dinner. Lean beef was the primary
nutrient-dense source of protein for each daily menu. Using blood samples and
thigh muscle biopsies, the researchers then determined the subjects' muscle
protein synthesis rates over a 24-hour period.
The UTMB researchers provided volunteers with a generous
daily dose of 90 grams of protein — consistent with the average amount
currently consumed by healthy adults in the United States. While very active
individuals may benefit from a slightly higher protein intake, the team's
previous research suggests that, for the majority of adults, additional protein
will likely have a diminishing positive effect on muscle metabolism, while any
less may fail to provide optimal muscle metabolism support.
When study volunteers consumed the evenly distributed
protein meals, their 24-hour muscle protein synthesis was 25 percent greater
than subjects who ate according to the skewed protein distribution pattern.
This result was not altered by several days of habituation to either protein
distribution pattern.
The results of the study, Paddon-Jones points out, seem to
show that a more effective pattern of protein consumption is likely to differ
dramatically from many Americans' daily eating habits.
"Usually, we eat very little protein at breakfast, a
bit more at lunch and then consume a large amount at night. When was the last
time you had just 4 ounces of anything during dinner at a restaurant?"
Paddon-Jones said. "So we're not taking enough protein on board for
efficient muscle building and repair during the day, and at night we're often
taking in more than we can use. We run the risk of having this excess oxidized
and ending up as glucose or fat."
A more efficient eating strategy for making muscle and
controlling total caloric intake would be to shift some of the extra protein
consumed at dinner to lunch and breakfast.
"You don't have to eat massive amounts of protein to
maximize muscle synthesis, you just have to be a little more thoughtful with
how you apportion it," Paddon-Jones said. "For breakfast consider
replacing some carbohydrate, particularly the simple sugars, with high-quality
protein. Throw in an egg, a glass of milk, yogurt or add a handful of nuts to
get closer to 30 grams of protein, do something similar to get to 30 for lunch,
and then moderate the amount of protein for dinner. Do this, and over the
course of the day you will likely spend much more time synthesizing muscle
protein."
No comments:
Post a Comment