Which is Better for Muscle Strength and Size, Protein in the Morning or at Night?
Title: Daytime and nighttime casein supplements similarly increase muscle size and strength in response to resistance training earlier in the day: a preliminary investigation
Author: Joy et al
Journal: Journal of the International Society of Sports Nutrition
Objective: To Compare supplemental casein consumed earlier in the day (DayTime, DT) versus shortly before bed (NightTime, NT) on body composition, strength, and muscle hypertrophy in response to supervised resistance training.
Casein is a type of dairy protein. Protein is essential for muscle growth and adaptation from resistance training. Protein intake is one of the most important factors for maximizing muscle strength and hypertrophy. Optimizing dietary intake over the course of the day remains an area of investigation to help maximize the benefits of protein consumption.
During sleep, food intake is digested and absorbed at rates similar to day time, hence the term ‘rest and digest’ to describe the parasympathetic state. Researchers have already shown that muscle protein synthesis occurs at night in response to prior resistance training and greater strength gains occur when protein is added.
Athletes are often discouraged from eating late due to the fear of increased fat production and loss of lean muscle mass. However, the timing of protein intake at night may actually increase lean muscle mass without a disruption of fat synthesis or breakdown. So the researchers of this study wanted to investigate if daytime versus nighttime casein intake had an effect on on body composition, strength and hypertrophy
This study included
- 13 males participated in a 10-week exercise and dietary intervention
- Consumed 35 g casein daily.
- Isocaloric diets provided 1.8 g protein/kg body weight.
Both groups increased (p < 0.05) in
- Lean soft tissue (DT Pre: 58.3 ± 10.3 kg; DT Post: 61.1 ± 11.1 kg; NT Pre: 58.3 ± 8.6 kg; NT Post: 60.3 ± 8.2 kg),
- Cross-sectional area (CSA, DT Pre: 3.4 ± 1.5 cm2; DT Post: 4.1 ± 1.7 cm2; NT Pre: 3.3 ± 1.6 cm2; NT Post: 3.7 ± 1.6 cm2)
- Strength in the leg press (DT Pre: 341 ± 87.3 kg; DT Post: 421.1 ± 94.0 kg; NT Pre: 450.0 ± 180.3 kg; NT Post: 533.9 ± 155.4 kg)
- Strength in bench press (DT Pre: 89.0 ± 27.0 kg; DT Post: 101.0 ± 24.0 kg; NT Pre 100.8 ± 32.4 kg; NT Post: 109.1 ± 30.4 kg)
There was with no difference between groups in any variable when comparing nighttime to daytime consumption of casein. (p > 0.05).
Individuals increased strength regardless of whether they took casein at night or during the day.
Per the authors, these findings support the strategy of targeting total protein intake rather than the timing of protein over the course of the day.
In other words, protein consumption before bed doesn’t appear to hurt you.
Joy JM, Vogel RM, Shane Broughton K, Kudla U, Kerr NY, Davison JM, Wildman REC, DiMarco NM. Daytime and nighttime casein supplements similarly increase muscle size and strength in response to resistance training earlier in the day: a preliminary investigation. J Int Soc Sports Nutr. 2018 May 15;15(1):24. Doi: 10.1186/s12970-018-0228-9. PubMed PMID: 29764464; PubMed Central PMCID: PMC5952515.