Does it matter when you eat your food? Well, it can. For the general population, it most likely doesn´t play a vital role, but for certain athletes, the nutrient timing could be something worth optimizing for best results.
There are a lot of different studies investigating the effects of macronutrient ingestion at different time points. However, many of these studies are somewhat different in study design (e.g. different amounts of macronutrients, slightly different timing, different outcome measurement (e.g. performance, muscle gain), calorie deficit etc). It can, therefore, be difficult to make any exact recommendations. What follows are thus some general guidelines that potentially could be beneficial in specific situations for healthy active individuals.
Try to consume at least 20-40 g of protein per meal and around 3-6 meals per day.
Muscle protein synthesis (MPS) rates (the muscle building process) can stay elevated for 3-5 h after consumption of protein, and is partly dependent on the protein dose (Kerksick et al., 2017). However, there has been speculation that consuming protein too frequently might actually blunt the muscle building effect. This idea stems from research showing that amino acid (building blocks of protein) levels stay elevated in the serum (part of the blood without all the cells and coagulated proteins) even after protein synthesis has gone down to baseline (after ~3 h, with a peak in MPS at 90 min). The hypothesis is therefore that a further increase in amino acid levels (due to ingesting more protein at this point), when amino acids are already above baseline and MPS has gone down, would give much benefit.
Hence, many recommend to space protein feedings at least ~3 h apart.
Protein feeding around workouts seem to be beneficial with regards to increases in MPS and strength, but the beneficial effects could be of less importance if recommended protein levels are met (~1.6-2.2 g protein/kg/day for active individuals). Muscle is sensitized to protein ingestion for >24 h after resistance exercise, meaning a greater MPS response in the following day after a training session. In short, it can’t hurt to time at least one of your daily protein feedings close to your workout.
Also, consuming a slow digesting protein (e.g. casein protein or protein in a mixed meal) within 30 min of sleep could increase MPS rates, improve strength and muscle hypertrophy (increases in muscle size).
For athletes, especially endurance athletes, glycogen is an especially important fuel source stored in the liver and muscles.
During activities at moderate to high intensity, glycogen is the main fuel source. Therefore, it could be beneficial to try to optimize the glycogen storage and utilization. Glycogen is synthesized from glucose which we get from carbohydrates. By loading with carbohydrates (maybe as high as 8-12 g carbohydrates/kg/day), the days leading up to a demanding race it is possible to maximize the glycogen storage.
If several long demanding exercise sessions are to be performed on the same day, strategies to optimize rapid glycogen resynthesis could be employed, e.g. 1.2 g low glycaemic index carbohydrates/kg/h, adding 0.8 g/kg/h protein, and 3-8 mg/kg caffeine (Kerksick et al., 2017).
During longer endurance races >60 min at higher intensities, 30-60 g of carbohydrates/h could be consumed to optimize performance.
I have not focused on fat in this text since fat seems to be of less importance short term for performance. However, fat is an essential part of the diet and the consumption of healthy fats should not be neglected.
To summarize, if you are an active individual (but not an elite athlete) eating a decent number of calories (in a caloric maintenance or surplus), aren´t training more than once a day and are consuming a decent amount of protein ~2 g/kg/day, you most likely will have small or negligible benefits of nutrient timing. I would, therefore, suggest you find a meal pattern that you like and can adhere to. However, spacing out protein intake of at least ~0.4 g/kg/meal on >2 meals is probably a good idea if you aim for improving body composition, muscle hypertrophy, and potentially performance.
Kerksick, C.M., Arent, S., Schoenfeld, B.J., Stout, J.R., Campbell, B., Wilborn, C.D., Taylor, L., Kalman, D., Smith-Ryan, A.E., Kreider, R.B., Willoughby, D., Arciero, P.J., VanDusseldorp, T.A., Ormsbee, M.J., Wildman, R., Greenwood, M., Ziegenfuss, T.N., Aragon, A.A., Antonio, J., 2017. International society of sports nutrition position stand: nutrient timing. J. Int. Soc. Sports Nutr. 14, 33. doi:10.1186/s12970-017-0189-4