Protein is an essential nutrient that helps the body grow and recover. Composed of long chains of amino acids, they promote the growth of skeletal muscles – these are the muscle groups that help us move.
People have long been aware of the benefits of protein. However, recent research shows that having the right amount of protein at the right time is essential for proper growth.
This is known as chrononutrition – which gives an idea of how important it is for you to eat, when you eat is also as important as how and what you eat.
The reason for this is the body’s internal biological clock.
This rhythm is known as the circadian rhythm and is followed by all cells and controls vital functions such as metabolism and growth.
Interestingly, it has been found that protein digestion and absorption varies during the day and night according to these hours.
In addition, previous studies have reported that eating protein at breakfast and lunch increases skeletal muscle growth in adults.
However, the details of the effects of protein absorption time on muscle growth and function remain elusive.
Fortunately, researchers at Waseda University, led by Professor Shigenobu Shibata, have recently tried to understand the effect of the distribution of daytime protein intake on muscle.
They fed laboratory mice a high (11.5% proportional) or low (8.5% proportional) protein concentration twice daily.
The researchers found that protein intake at breakfast resulted in increased muscle growth, as determined by evaluating the induced hypertrophy of the plantar muscles in the legs versus the effect of protein intake at dinner.
Specifically, the ratio of muscle hypertrophy to control of muscle growth in mice fed 8.5% protein for breakfast was 17% higher than in mice fed 11.5% protein at dinner, even though the former group was low in protein overall.
They also found that consuming a type of protein called BCCA — short for branched-chain amino acids — increased skeletal muscle size earlier in the day.
They repeated the experiment with the food distribution of these mice, but did not observe similar muscle changes, confirming the involvement of circadian rhythms in protein intake-related muscle growth.
Excited by the results of their research, published in the latest issue of Cell Reports, Professor Shibata emphasized: “Eating a high protein diet in the early phase of an active daily life, i.e. breakfast, is important for maintaining healthy skeletal muscles and an increase in muscle volume and grip strength.”
To test whether their results could be transferred to humans, the team recruited women into their study and tested whether their muscle function, as determined by measuring skeletal muscle index (SMI) and traction strength, with a high-protein diet varied over time.
Sixty women aged 65 years and over who ate protein for breakfast rather than dinner demonstrated better muscle function, suggesting that the results apply to all species. In addition, the researchers also found a strong relationship between SMI and the percentage of protein intake at breakfast in relation to total protein intake during the day.
Professor Shibata hopes his research will bring about a major change in the diet of most people in Western and Asian countries today who traditionally eat low amounts of protein for breakfast.
Therefore he emphasizes: “In general, the average human protein intake at breakfast is about 15 grams, less than what we eat at dinner, which is about 28 grams.
“Our results strongly support changing this norm and consuming more protein at breakfast or at breakfast.”
Relatively high protein foods that don’t feel too filling in the morning include eggs, tofu, flaxseed, oatmeal, chia, and nuts.
It seems that a simple change in diet can be our key to healthy muscles.