Chrononutrition: Protein at breakfast may boost strength and muscle growth

20 Jul 2021 --- Protein intake at breakfast induces an increase in muscle growth when compared with the effects of protein intake at dinner, according to researchers from Waseda University, Japan. 

“A protein-rich diet at breakfast is important to maintain skeletal muscle health and enhance muscle volume and grip strength,” comments professor Shigenobu Shibata, who led the research.

Shibata is hopeful that the findings of their study will lead to a widespread modification in the current diet regime of most people across the Western and Asian countries, who traditionally consume low amounts of protein at breakfast. 

“For humans, in general, the protein intake at breakfast averages about 15 g, which is less than what we consume at dinner, which is roughly 28 g. Our findings strongly support changing this norm and consuming more protein at breakfast or morning snacking time.”

Importance of protein type
Published in Cell Reports, the study set out to understand the effect of protein intake distribution throughout the day on muscles. 

Eating a protein-rich diet can help increase muscle growth and strength.

The researchers found that intake of branched-chain amino acids (BCCA) early in the day increased the size of skeletal muscles.

The researchers fed laboratory mice two meals per day containing either high (11.5 percent by proportion) or low (8.5 percent by proportion) protein concentrations. 

The results were determined by assessing the induced hypertrophy of the plantaris muscle, which is located in the leg.

Specifically, the ratio of muscle hypertrophy determined against the growth of the control muscle was 17 percent higher in mice fed 8.5 percent protein at breakfast than in mice fed 11.5 percent protein at dinner – despite the former group consuming a low proportion of protein overall. 

To confirm the association of these effects with the workings of the circadian rhythm, the researchers next engineered whole-body mutant ClockΔ19 or muscle-specific Bmal1 knockout mice lacking the genes that control the biological clock. 

They repeated diet distribution experiments on these mice but did not observe similar muscle change, which confirmed the involvement of the circadian rhythm in muscle growth in the context of protein intake.

Human testing
To check if their findings were applicable to humans, the team recruited women in their study.

The researchers found that intake of BCCA early in the day increased the size of skeletal muscles.They tested if their muscle function, determined by measuring skeletal muscle index (SMI) and grip strength, varied with the timing of the protein-rich diet consumed. 

Sixty women aged 65 years and above who took protein at breakfast rather than at dinner showed better muscle functions, suggesting the possibility of the findings to be true across species. 

Additionally, the researchers also found a strong association between SMI and the proportion of protein intake at breakfast relative to total protein intake throughout the day.

Eating in good timing
The study builds on the concept of “chrononutrition,” in which when you eat is as important as what and how you eat.

The reason behind this is the body’s circadian rhythm. This biological clock is followed by all cells and controls life functions like metabolism and growth. 

Protein digestion and absorption have been found to fluctuate across day and night according to this clock. 

Moreover, earlier studies have reported that intake of protein at breakfast and lunch promotes skeletal muscle growth in adults. 

However, details on the effect of the time of protein intake on muscle growth and function have remained elusive to date.

Dr. Michael Roizen, chief wellness officer at the Cleveland Clinic and chairman of the Medical Advisory Board for Persona (Nestlé Health Science), previously noted that while personalized nutrition is reaching mainstream status, chrononutrition has great potential to add a new dimension to this trend.

Furthermore, InnoBev introduced BioLift, a beverage featuring natural ingredients, to help consumers maintain energy levels throughout the day and avoid a “post-lunch dip.” 

Using the science of “chronobiology,” or the rhythm associated with internal biological clocks, BioLift’s functional properties help consumers bypass tiredness typically arising in the early afternoon when the human body is prone to drowsiness.

Edited by Kristiana Lalou