In a recent study, researchers found that an even distribution of protein intake throughout the day resulted in greater net whole-body protein balance compared to an uneven distribution.
They were studying whether the distribution of daily protein intake influences net whole-body protein balance (the primary outcome) and muscle protein synthesis (MPS) rates. MPS is the process by which skeletal muscle makes new proteins – dietary protein intake is a key factor in stimulating MPS – and the balance between this and muscle protein breakdown (MPB) determines muscle mass over time.
In this 10-day randomized controlled trial, 24 participants consumed 1.5 grams of protein per kilogram of lean body mass per day. Protein intake was divided in one of two ways:
- EVEN: 30% of protein intake was consumed at each of the three main meals
- SKEWED: 15% of protein intake was consumed at breakfast, 15% at lunch, and 60% at dinner
They found that consuming moderate amounts of protein every three hours leads to greater MPS rates, compared to consuming low or large doses at different intervals. An even distribution of protein intake throughout the day may result in a more positive net muscle protein balance, and better muscle preservation with aging. 
This all said, other studies have yielded seemingly contradictory findings, and the key difference between them being the source of protein. Meals consisting of whole foods were consumed in some studies, while others used isolated protein supplements like milk or whey. This nutrient and nonnutrient component of the foods, and their molecular relationships, affected the absorption rates of amino acids. As the study authors speculated “when protein is ingested as part of a mixed meal, the peak MPS response could be lower and more prolonged with less impact of an EVEN or SKEWED distribution pattern.”
More research is needed using whole food meals. Bottomline, it is recommended that older adults consume protein at least 3-4 times daily, about 3-5 hours apart. 
To check out the whole summary of the study, click here.
- José L Areta, Louise M Burke, Megan L Ross, Donny M Camera, Daniel W D West, Elizabeth M Broad, Nikki A Jeacocke, Daniel R Moore, Trent Stellingwerff, Stuart M Phillips, John A Hawley, Vernon G CoffeyTiming and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesisJ Physiol.(2013 May 1)
- Aragon AA, Tipton KD, Schoenfeld BJAge-related muscle anabolic resistance: inevitable or preventable?Nutr Rev.(2023-Mar-10)