NUTRIENT TIMING IN EXERCISE
Nutrient timing is a planned alteration of macronutrient intake in order to promote health, workout performance, and get/stay lean. Nutrient timing strategies are based on how the body handles different types of food at different times. When you exercise regularly, the body is primed for fat gain or fat loss just as it’s primed for muscle gain or muscle loss during specific times of the day. The wrong foods at the wrong times sabotage your efforts in the gym. The right foods at the right times enhance those efforts.
NUTRITION FACTORS CAUSING FATIGUE
There are nutrition factors that can lead to fatigue:
- Depletion of glycogen stores
- Low blood sugars (hypoglycemia) – can happen when you don’t have enough carbs
Gastrointestinal upset & discomfort
Optimum sports nutrition is based on the principle of implementing nutrition strategies that can reduce or delay the onset of factors that cause fatigue and impair performance.
NUTRITION BEFORE EXERCISE
Why is nutrition important before exercise?
- Maximise glycogen stores
- Ensure liver glycogen stores are filled
- Optimal hydration status
- Avoid starting out hungry, whilst avoiding gastrointestinal discomfort
Nutrition timing is individualized. We do need to experiment with the timings of your pre-exercise, during exercise and post exercise snacks to determine the best time to consume nutrients for optimal advantage.
CARBOHYDRATES BEFORE EXERCISE
To perform optimally adequate amounts of carbohydrates needs to be supplied to the body prior to exercise. The source, quantity and timing of the carbohydrate consumed that can lead to either a high energy high performance exercise session or to a feeling to fatigue and impaired performance.
4 – 24 hours before (mainly for prior to competitions)
- Carbohydrates should compose the majority of each meal and snack
- Aim 60-70% of the total calories coming from carbohydrates
- Always aim to have a full tank when you begin exercising
1 -4 hours before exercise
- Aim to consume food and drinks that can be easily digested
- Avoid going into training session/event hungry
- Aim for 1 – 4g per kg of body weight of carbohydrates
e.g. 65kg cyclist aims for 1-4g per kg body weight in the 4 hours prior to event is 65 – 260g of carbs.
The carbohydrate requirement of 1-4g can be split as meals or snacks. Here are some examples of snacks and meals for supplying high GI carbs:
PROTEIN BEFORE EXERCISE
Don’t overlook protein with pre-exercise meals and snacks
Adding protein into pre-exercise nutrition has several benefits
- Increases muscle synthesis
- Decreases muscle protein breakdown
- Gradual delivery of nutrients
- Delays onset of hunger
4 – 24 hours before
Similar to general guidelines discusses with protein in the diet in the previous article.
1 -4 hours before exercise
- 50 – 110g of protein that should be broken down into 2 to 3 portions
- Need to find balance between pre-exercise protein and carbohydrates
- Avoid protein sources high in fat as it takes longer to digest
Common sources of protein – each portion contain approximately 10gof protein
FAT BEFORE EXERCISE
Fat prior to exercise:
- Increases satiety
- Avoid fat in the 4 hour prior to exercise can cause bloating, cramping or even diarrhea
- May cause gastrointestinal distress – only recommended amount not a high fat diet
- Experiment during training season to establish personal tolerance levels
NUTRITION DURING EXERCISE
CARBOHYDRATES DURING EXERCISE
- Delays fatigue in both long and short duration events
- Reduced reliance on stored glycogen
- Provides alternative sources of energy when glycogen levels are depleted
- Requirements will vary according to individuals
Focus on glucose, sucrose, maltodextrins and starches will be what you need to concentrate on. Products that contain a mix of sugars may be valuable. Consume in training lasting more than 60 minutes. If you are training for 60 minutes or less you do not need to concentrate on adding carbs during the exercise.
Quantity required is determined by 2 main factors;
- Rate of gastric emptying and intestinal absorption
- Rate of consumed carbohydrates used by the muscle
If you exercise more than 60 minutes, consume between 30 to 90g per hour. Always experiment to see what suit you personally. Sport drinks/carbohydrates gels are convenient sources
PROTEIN DURING EXERCISE
Protein ingestion during exercise thought to improve performance by:
- Energy production
- Reduction in fatigue
- However currently no conclusive research
- No established guidelines
Any protein during exercise does not give you energy. Some companies like to market their product esp. BCAAs, however it hasn’t be proven that consuming protein during an exercise has any advantage. So, folks focus on just our workout.
FAT DURING EXERCISE
Not recommended at all and can have bad effects like gastro intestinal discomfort.
NUTRITION POST EXERCISE
CARBOHYDRATES POST EXERCISE
Moderate intensity/duration exercise – partially depleted glycogen stores
High intensity/long duration exercise – completely depleted glycogen stores
Hence, it is vital to replace these stores post exercise. Moreover, muscle absorb blood glucose and restore glycogen at high rates with carbohydrates are ingested within 2 hours after you have been training.
Aim for high GI carbohydrates
Aim for 1 -1.5g per kg body weight
Best aim for post workout snack with 15 to 30 mins of workout completion
And then every 2 hours for 6 hours
Protein is critical for recovery. After exercise, protein breakdown is reduced and protein synthesis increases. Aim for sources that cause hyper aminoacidemia(loss of amino acid in the blood). Whey and casein protein are high quality protein and contain high amount of branched chained amino acids. Soy protein is also a good source of high quality protein. Consumption of essential amino acids soon after exercise is of high importance. Hypertrophy occurs when muscle synthesis is higher than muscle breakdown.
Combining carbohydrates and protein enhances recovery. The combination also enhances protein and carbohydrate intake into muscle cells, including high uptake of amino acids
Aim for a 3:1 ratio of carbohydrates to protein.
|500ml Chocolate Milk||60g||20g|
|1 Banana and 2 boiled eggs||31g||12g|
|2 slices wholegrain toast & 1.5Tbsp peanut butter||32g||12g|
|120g Brown Rice and 60g Chicken||55g||17g|
|Smoothie: 500ml low fat milk, 100g berries, 1 Tbsp honey||52g||17g|
|85g tofu, 1.5 cups mixed veg, 1 cup brown rice||20g||8g|
|1 Pear, 50g Cashew nuts||42g||10g|
FAT POST EXERCISE
It is not essential to replace fats post exercise. Training will not deplete fat stores not even after an intense endurance workout. So, fats in the diet should be kept at a minimum. Fat induces slow gastric emptying which may affect carbohydrate and protein absorption. It is not something to focus on.
Nutrient timing is an important strategy, but it’s not for everyone. Nutrient timing can be helpful. Or it can add layers of unnecessary complexity. It all depends on the context.
If you’re new to healthy eating, don’t worry about timing for now. Start by improving the overall quality of your food and incorporating the basic nutrition habits into your life. Once you build a foundation of nutritious eating, then consider adding the nutrient timing habit.
If you are lean and simply want to maintain your existing body composition, consume more carbohydrates throughout the day will likely be fine.
If you want to lose body fat, first control overall food intake, then aim to consume a majority of carb dense foods during and after exercise sessions (for about 3 hours after). Outside of the 3 hour window consume primarily protein and fat, while consuming fewer carb dense foods (25% of less of meal made up of carb dense foods).
If you want to gain muscle, the nutrient timing principles are similar – simply add more calories overall.
In all cases: Assess your progress and adjust as necessary, consult a dietitian for an individualized plan.
- Aragon AA, Schoenfeld BJ. Nutrient timing revisited: is there a post-exercise anabolic window? J Int Soc Sports Nutr. 2013 Jan 29;10(1):5.
- Aragon AA. Continuum of nutrient timing importance (original schematic). NSCA Personal Trainers Conference. April 2012.
- Cribb PJ, Hayes A. Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy. Med Sci Sports Exerc. 2006 Nov;38(11):1918-25.
- Garaulet M, Gómez-Abellán P, Alburquerque-Béjar JJ, Lee YC, Ordovás JM, Scheer FA. Timing of food intake predicts weight loss effectiveness. Int J Obes (Lond). 2013 Apr;37(4):604-11.
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