Nutrient timing has recently become a popular topic in the fitness industry. Nutrient timing is the concept of certain macronutrients being consumed at certain periods throughout the day and also around your workouts. Two questions are often asked about nutrient timing:
1. "How often throughout the day should I consume certain macros?"
2. "Does the timing vary depending on my workouts?"
These are great questions and we will dive into it a bit deeper. Below is each macronutrient broken down to better understand the science behind nutrient timing.
There is evidence that show similarities in the development of muscle metabolism and protein feeding. The muscle is a dynamic tissue that constantly grows and shrinks throughout the day. That being said it is extremely beneficial to have a constant supply of amino acids (broken down proteins) in GI tract to promote muscle growth and repair. Protein, unlike fats and carbohydrates, do not have a storage mechanism in the body. Fats are able to be stored as adipose tissue, while carbohydrates are stored as glycogen in the muscle and liver. Proteins are broken down, absorbed and whatever cannot be absorbed is flushed out. The only way to get more protein in the body is to consume it. If we are not taking in protein then our body will naturally take amino acids from the next best source, which would be other muscle tissue, because our body still has to repair and contract. Breaking down one muscle to help grow another does not sound like a sustainable process. Protein needs to be consumed in a sufficient amount and consumed in a way to continuously supply amino acids to the bloodstream. The issue with developing a consistent method for the frequency of protein consumption is how to get a consistent amount during the day. We need to consume protein every 3-5 hours so we do not have periods without amino acids in the bloodstream. The exact timing aspect of protein is minimal. You can consume protein after you work out and data shows that it slows catabolism and promote anabolism. However, the actual muscle growth will occur 2-3 days after training not in the hours post training.
Carbohydrate timing is more complex than protein timing. How often you eat protein is more important than timing it around workouts. However, it is the opposite for carbohydrates. The frequency of carb intake is not really an issue until we are consuming vast amounts of carbohydrates. In that case, carbohydrate consumption can become too large to be synthesized into glycogen stores and deposited more as a fat. Therefore, the timing of carb intake becomes more important to increase its frequency throughout several meals.
Timing carb intake as it relates to physical activity has several distinct phases. The first window would be the pre-workout phase. The pre-workout phase is important in replacing glycogen stores, which supplies blood glucose (Energy) to the nervous system and muscles for contraction. Having full glycogen stores will allow better workout performances. Carbohydrates also have been shown to be helpful in preventing muscle loss when ingested during the pre-workout phase. For this to be effective pre-workout carbs would need to be consumed 1-3 hours before training.
The next phase is post workout carbs which have similar effects as pre-workout carbs. They have an anti-catabolism mechanism as well as glycogen repletion and will activate anabolic effects. Protein combined with carbs helps to blunt the catabolism process. These carbs help with glycogen repletion so we do not have chronically low glycogen stores effecting workout performance and muscle growth. Consuming carbs right after training helps with the likelihood of those carbs being used as glycogen. The alternative is being converted to fat stores at rest. The anabolic affects occur by spiking insulin. Insulin stimulates muscle growth upon binding to the muscle cell surface. Post-workout carbs show a lot of benefit for your performance and your absorption for glycogen stores. They need to be consumed in a 1:1 ratio as your pre-workout carbs. Then the rest of your carbs, which isn’t much, should be spread throughout your remaining meals.
The last macro to worry about for nutrient timing is fats. Fats are very difficult to digest. They slow down digestion of proteins and lower the glycemic index of carbs. They slow down your digestion of proteins from one to seven hours depending on how much fat is consumed with the protein. Fats need to be consumed away from your workouts. This way they do not affect the nervous system functionality and glycogen stores of which carbs are trying to promote. There are exceptions for endurance athletes training for several hours due to the specific energy system they are training because they will be burning more fats during that state.
Now that we have talked about the different timings of the different macros, I find it important to also tell you how important nutrient timing is to weight loss. When you total up all the variables to consider when losing weight, timing falls 3rd in line. Caloric balance and macronutrient amounts take the top 2 spots. A deviation from either one of these will make or break a diet plan. As long as you get your calories and macros right, timing is a much smaller concern. Research shows that nutrient timing is responsible for at most about 20% and possibly as little as 10% to the total impact of a diet plan. For those trying to obtain the loss of those last few pounds need to be more conscientious about their intake timing in order to make the biggest difference. That 10% for a top level athlete could mean the difference between 1st and 3rd. If you want the best possible results, then nutrient timing could be something to consider.