Glucose Plus Fructose Ingestion For Post-Exercise Recovery—Greater Than The Sum Of Its Parts?

[paymanz]

Nutrients. 2017 Apr; 9(4): 344.
Published online 2017 Mar 30. doi: 10.3390/nu9040344
PMCID: PMC5409683
PMID: 28358334

Glucose Plus Fructose Ingestion for Post-Exercise Recovery—Greater than the Sum of Its Parts?


Abstract
Carbohydrate availability in the form of muscle and liver glycogen is an important determinant of performance during prolonged bouts of moderate- to high-intensity exercise. Therefore, when effective endurance performance is an objective on multiple occasions within a 24-h period, the restoration of endogenous glycogen stores is the principal factor determining recovery. This review considers the role of glucose–fructose co-ingestion on liver and muscle glycogen repletion following prolonged exercise. Glucose and fructose are primarily absorbed by different intestinal transport proteins; by combining the ingestion of glucose with fructose, both transport pathways are utilised, which increases the total capacity for carbohydrate absorption. Moreover, the addition of glucose to fructose ingestion facilitates intestinal fructose absorption via a currently unidentified mechanism. The co-ingestion of glucose and fructose therefore provides faster rates of carbohydrate absorption than the sum of glucose and fructose absorption rates alone. Similar metabolic effects can be achieved via the ingestion of sucrose (a disaccharide of glucose and fructose) because intestinal absorption is unlikely to be limited by sucrose hydrolysis. Carbohydrate ingestion at a rate of ≥1.2 g carbohydrate per kg body mass per hour appears to maximise post-exercise muscle glycogen repletion rates. Providing these carbohydrates in the form of glucose–fructose (sucrose) mixtures does not further enhance muscle glycogen repletion rates over glucose (polymer) ingestion alone. In contrast, liver glycogen repletion rates are approximately doubled with ingestion of glucose–fructose (sucrose) mixtures over isocaloric ingestion of glucose (polymers) alone. Furthermore, glucose plus fructose (sucrose) ingestion alleviates gastrointestinal distress when the ingestion rate approaches or exceeds the capacity for intestinal glucose absorption (~1.2 g/min). Accordingly, when rapid recovery of endogenous glycogen stores is a priority, ingesting glucose–fructose mixtures (or sucrose) at a rate of ≥1.2 g·kg body mass−1·h−1 can enhance glycogen repletion rates whilst also minimising gastrointestinal distress.

Skeletal muscle glycogen provides a rapid and efficient (energy yield per unit oxygen) fuel source for energy expenditure, such that when skeletal muscle glycogen stores are depleted, the rate of energy production is severely compromised. Clear support for the important role of glycogen as a substrate in supporting energy requirements to allow intense exercise is provided by observations of individuals with McArdle’s disease (glycogen storage disease type V; GSD5). These individuals display high skeletal muscle glycogen concentrations but an inability to utilise this glycogen as a substrate source [40], and subsequently can also display extreme intolerance to intense exercise [41]. This is partly due to glycogen oxidation resulting in maximal ATP re-synthesis rates that are >2-fold greater than fat or plasma glucose oxidation [42,43]. Therefore, when high rates of ATP re-synthesis are required over a prolonged duration, it would appear there is no substitute for glycogen as a fuel. Furthermore, the oxidation of carbohydrates is more oxygen efficient than that of fat, deriving more energy per litre of oxygen consumed [44]. Consequently, oxidising carbohydrates over fats provides an advantage in sports where the rate of oxygen delivery to active muscle is limiting to performance.

Rodent data suggest that liver glycogen contents modulate fatty acid availability via a liver–brain–adipose tissue axis [50]. Therefore, brain sensing of liver glycogen contents could regulate metabolism (and theoretically faigue) during exercise.

Macronutrient considerations for the sport of bodybuilding. - PubMed - NCBI

The optimal rate of carbohydrate ingested immediately after a training session should be 1.2 g/kg/hour at 30-minute intervals for 4 hours and the carbohydrate should be of high glycaemic index.

 

[Geronimo]

I think this is essential info for a lot of people, potentially millions. Imagine how many people gorge on glucose (without fructose) in the form of rice and bread. The ensuing indigestion, starch fermentation, and elevated blood glucose is an absolute disaster for people who aren't lifting weights and/or have slow metabolisms. Not to mention the low liver glycogen from a lack of fructose and thus the further inhibition of thyroid function and hormone metabolism. Add all of this to a messed-up overgrown gut biome and you've got a recipe for disaster. Anyone who struggles with energy, digestion and metabolism should absolutely drop starches in favor of sucrose, no matter how much saturated fat you dump into the starches. I know this is kind of a fundamental Peat principle in his mind, but I think it gets overlooked alot in the forum.

 

[shine]

Nutrients. 2017 Apr; 9(4): 344.
Published online 2017 Mar 30. doi: 10.3390/nu9040344
PMCID: PMC5409683
PMID: 28358334

Glucose Plus Fructose Ingestion for Post-Exercise Recovery—Greater than the Sum of Its Parts?


Abstract
Carbohydrate availability in the form of muscle and liver glycogen is an important determinant of performance during prolonged bouts of moderate- to high-intensity exercise. Therefore, when effective endurance performance is an objective on multiple occasions within a 24-h period, the restoration of endogenous glycogen stores is the principal factor determining recovery. This review considers the role of glucose–fructose co-ingestion on liver and muscle glycogen repletion following prolonged exercise. Glucose and fructose are primarily absorbed by different intestinal transport proteins; by combining the ingestion of glucose with fructose, both transport pathways are utilised, which increases the total capacity for carbohydrate absorption. Moreover, the addition of glucose to fructose ingestion facilitates intestinal fructose absorption via a currently unidentified mechanism. The co-ingestion of glucose and fructose therefore provides faster rates of carbohydrate absorption than the sum of glucose and fructose absorption rates alone. Similar metabolic effects can be achieved via the ingestion of sucrose (a disaccharide of glucose and fructose) because intestinal absorption is unlikely to be limited by sucrose hydrolysis. Carbohydrate ingestion at a rate of ≥1.2 g carbohydrate per kg body mass per hour appears to maximise post-exercise muscle glycogen repletion rates. Providing these carbohydrates in the form of glucose–fructose (sucrose) mixtures does not further enhance muscle glycogen repletion rates over glucose (polymer) ingestion alone. In contrast, liver glycogen repletion rates are approximately doubled with ingestion of glucose–fructose (sucrose) mixtures over isocaloric ingestion of glucose (polymers) alone. Furthermore, glucose plus fructose (sucrose) ingestion alleviates gastrointestinal distress when the ingestion rate approaches or exceeds the capacity for intestinal glucose absorption (~1.2 g/min). Accordingly, when rapid recovery of endogenous glycogen stores is a priority, ingesting glucose–fructose mixtures (or sucrose) at a rate of ≥1.2 g·kg body mass−1·h−1 can enhance glycogen repletion rates whilst also minimising gastrointestinal distress.





Macronutrient considerations for the sport of bodybuilding. - PubMed - NCBI

So a 80kg person should consume 384g of carbs over the course of 4 hours after a workout session?

 

[Vinny]

So a 80kg person should consume 384g of carbs over the course of 4 hours after a workout session?

Anyone?

 

[famalalam]

So a 80kg person should consume 384g of carbs over the course of 4 hours after a workout session?

Sounds like too much. I interpret it as 1.2g * bodyweight in kilos * hour / 8
That could for example be (1.2 * 80 * 1) / 8 = 12
If you worked out for an hour, you should eat 12g of carbohydrates every 30 minutes for 4 hours. But I'm probably wrong and only add to the confusion.

 

[Minimal]

Anyone?

no thanks

 

[shine]

Sounds like too much. I interpret it as 1.2g * bodyweight in kilos * hour / 8
That could for example be (1.2 * 80 * 1) / 8 = 12
If you worked out for an hour, you should eat 12g of carbohydrates every 30 minutes for 4 hours. But I'm probably wrong and only add to the confusion.

That sounds like too little, considering that muscles can store about 400g of glycogen.
I think 48g every 30mins is more reasonable, even though it is a lot.
1.2 * 80 * 1 = 96
96 * 0.5 = 48

Guys like Jay Cutler ate like 900g of carbs at 140 kg bodyweight.

I will try this out on training days to see if it influences my recovery. I'll keep my carbs at 250g on rest days.