The idea behind nutrient timing was based on research that showed eating specific nutrient combinations of primarily carbs and protein in and around the post-workout period could cause an anabolic response that resulted in stimulating glycogen replenishment (i.e., the energy your muscles need to workout) and protein synthesis (i.e., the muscle building). In fact, this timeframe was considered the most critical for making a full recovery from exercise and was given the name by many researchers as the “anabolic window of recovery.” What is this anabolic window exactly? And, what does the research say actually say about it? Keep reading to find out more.
What Happens During A Workout?
Understanding how both the anabolic and catabolic hormone systems are regulated was considered a key to controlling when your body is in a building phase and when it is in a burning phase. During exercise, the body releases and elevates the catabolic hormones resulting in the breakdown of glycogen into a useable form of glucose or fuel for the body. Providing the body with specific nutrient ratios of protein and carbs during the post-workout timeframe was thought to help preserve muscle and prevent muscle breakdown from occurring while stimulating muscle-building pathways. Manipulating the shuttling hormone insulin during the anabolic window was thought to minimize catabolic processes and optimize muscle protein synthesis (growth and repair).
Switching from Catabolism to Anabolism
One of the most important nutrients that impacts insulin is carbohydrate. Manipulating insulin response post-workout was thought to counteract the catabolic post-workout state and switch to an anabolic one allowing for a more speedy recovery! By consuming a high ratio of carbohydrates to protein in a 2:1 ratio, low glycogen and amino levels could be restored. A positive insulin response could therefore increase muscle glycogen replenishment and increase protein and amino uptake into the muscle to trigger protein synthesis. Although this might seem pretty simple and rational, in actuality, most individuals who train never get to a point where they would truly be in a catabolic state.
What Does the Research Say?
Most studies that showed the positive effects of an anabolic window were completed on highly trained individuals who trained fasted or semi-fasted. In fact, eating prior to your workout can do enough of spiking insulin to prevent catabolism. What’s more, carbohydrates are not the only nutrient that can elicit an anabolic response. In fact, protein can also have an insulinogenic response! One study showed that when supplementing with 6 g of essential amino acids immediately before exercise, muscle amino levels were elevated by 130% and remained elevated for two hours post-workout.
In another study, pre-exercise consumption of 20 g of whey elevated muscular uptake of aminos 4.4 times pre-exercise resting levels during exercise and didn’t return to baseline levels until three hours post-exercise. These studies show that consuming a pre-workout supplement of either a protein or amino acids can help sustain amino acid delivery to muscles post-workout, eliminating the need for a huge spike in blood sugar from a source of simple carbohydrates!
How Can You Apply Nutrient Timing?
Bottom line, consistently providing the body with sufficient nutrients will help to remain in an anabolic state. Going longer than 3 hours between meals may result in nutrient depletion and thus reduce anabolic processes. However, true depletion of glycogen and aminos from your muscles is dependent on your personal needs.
The amount of calories and macronutrients your body needs will be determined by your activity level, your metabolism, how well you metabolize carbohydrates, your level of body fat and your genetics! Women tend to reserve their glycogen and switch to fat as fuel over carbs! There is no one-fits-all method for everyone.
One study even showed a non-traditional meal of 47% carbs, 26% protein and 27% fat was found to raise insulin three times above fasting levels within 30 minutes of consumption, while at 60 minutes insulin was five times better.
If your goal is to achieve a muscular, fit body, you will need to eat a high protein diet, with a moderate amount of carbs and fat, and nutrient timing can help you maximize this process. Pay attention to how your body feels and responds to what you feed it and when you feed it. Make adjustments based on your own unique requirements and needs.
Aragon A, Schoenfeld BJ. Nutrient timing revisted: is there a post-exercise anabolic window. JISSN. 2013. 10: 5.
Burke, LM, et al. Carbohydrates and fat for training and recovery. J Sports Sci. 2004. 22:15-30.
Gibala, MJ. Nutritional supplementation and resistance exercise: what is the evidence for enhanced skeletal muscle hypertrophy. 2001. Can J Appl Physiol. 2000. 25(6): 524-535.
Levenhagen, DK, et al. Postexercise nutrient intake timing in humans is critical to recovery of leg glucose and protein homeostasis. Am J Physiol Endo Metab. 2001. 280: 982-993.
Volek, JS. Influence of Nutrition on Response to Resistance Training. Med Sci Sports Exerc. 2004. 36(4): 689-696.
Volek, JS, et al. Nutritional aspects of women strength athletes. Brit J Sports Med. 2006. 40: 742-748.