glucosio vs fruttosio

[sh4dow]

Per il drink post-allenamento è meglio usare glucosio o fruttosio? Quale può essere un carboidrato semplice ancora più adeguato?

[esiclene]

Re: glucosio vs fruttosio

Originally posted by sh4dow
Per il drink post-allenamento è meglio usare glucosio o fruttosio? Quale può essere un carboidrato semplice ancora più adeguato?

Glucosio o Destrosio post workout. Il fruttosio lo escluderei..

[MISTER X]

i carob devono essere ad alto ig,quindi per nulla fruttosio,il carboidrato con IG + basso.

il migliore è il destrosio,il carbo con ig + alto(hanno ig + alto solo maltosio e tofu).

[billy_80]

hanno ig + alto solo maltosio e tofu).

non penso proprio che il tofu(formaggio di soia)abbia ig più alto del glucosio. Forse ti riferivi al tofu frozen dessert che peraltro non so nemmeno cosa sia

bye

[bart]

2 cucchiaini di miele possono andare?e una banana?

[swanz]

Si, miele e banana vanno bene.

x sh4dow: il fruttosio è uno zucchero semplice, ma paradossalmente ha un IG basso, infatti dovrà essere convertito in glucosio (e tale processo ne rallenta l'assimilazione).

Meglio il glucosio quindi.

[lo zar]

Il Fruttosio fa ingrassare !!!!!

Ecco, ho trovato lo spunto giusto per inserirlo questo interessante articolo proprio su fruttosio/glucosio..........

Paradossalmente (reggetevi!!, ma con l'intuito l'avrete spesso toccato questa conclusione ) il fruttosio è uno zucchero che rischia (anzi direi fa!!) di farci aumentare i rotolini di fats.......
Lo so lo so...nn ci crederete voi......;leggetevi questo articolo e nn crederete ai vostri occhi.....



The old adage that your body is a temple is well known and still has relevance today. Without a solid foundation a temple can not be successfully constructed and will eventually collapse. The same holds true for the human body. We at ISSA strive to educate our trainers regarding the synergism between proper exercise, nutrition and behavior modification to effectively draw their clientele into not just a good lifestyle, or even a better lifestyle, but the best way of life; a fitness lifestyle.

The importance of nutrition is imperative as the foundation of any successful fitness program. The core of this foundation should be based around food. Just as certain compounds are necessary to build a solid foundation in a building, specific foods are necessary to build a solid nutritional foundation. Since we have already discussed which foods aid in building this foundation through past articles, we will focus our attention on why certain foods that are considered healthy, actually may not aid in fat reduction.

With the advent of so many nutritional approaches to achieve the ideal look, numerous inquiries regarding the practice of omitting fruit, fruit juices or any of its derivatives from a diet have surfaced. Fruit is a healthy food, full of nutrients, high in fiber, vitamins, minerals, and low in fat and calories. It is a common practice for bodybuilders during pre-contest preparation to omit fruit from their diets, as it should be for anyone looking to minimize bodyfat. We will discuss the chemistry behind the efficacy of this practice.

Our bodies can only absorb monosaccharides (glucose, galactose, or fructose), the single units of sugars and starches. Once absorbed through the small intestines into the portal vein, and then circulated into the bloodstream through the liver as blood glucose, our bodies can put glucose to work in three ways:

It can burn the glucose immediately for energy if blood glucose levels are not at a stable level of 20 grams blood borne glucose circulating per hour.


If it is not needed for energy immediately, then it is converted into glycogen in the liver or muscles. The liver has the capacity to store 100 grams of glycogen. The muscles have the capacity to store between 250-400 grams of glycogen, depending on muscle mass and physical condition. Liver glycogen supplies energy for the entire body. Muscle glycogen only supplies energy to muscles.


If the body has an excess of glucose, and all of the glycogen stores are full, the surplus glucose is converted to fat by the liver and stored as adipose tissue (bodyfat) around the body. If needed, fatty acids can be burned as fuel (BUT the fat cannot be converted back to glucose).

Now that we have outlined how our bodies use glucose, we will discuss why fruit (fructose or fruit sugar) is detrimental in an attempt to maximize fat loss. Since muscles have the specific purpose of contraction, they have a limited number of enzymes for glycogen synthesis. Muscle only has the necessary enzymes to convert glucose (and nothing else) into glycogen. The liver, however, is able to make glycogen from fructose, lactate, glycerol, alanine, and other three-carbon metabolites. Muscle glycogen, which is similar in structure to starch, is an amylopectin (branched chained polymer containing hundreds of glucose units). Unlike muscles, which can only supply energy to themselves through the stored 250-400 grams of glycogen, the liver is responsible for supplying energy to the entire body.

If you have fruit, fruit juice, or any of its derivatives, the following conditions occur:

Referring to the three ways the body uses glucose, assuming that blood glucose levels are adequate, the glucose will then be stored as glycogen. Muscle does not have the necessary enzymes to synthesize fructose into glycogen; therefore the liver converts this fructose into liver glycogen. It would only take three, 8-ounce glasses of orange juice to fully replenish liver glycogen stores. Since the liver is responsible for supplying energy to the entire body, once its stores are full, a rate limiting enzyme in glucose metabolism which is responsible for signaling the body to store glucose as glycogen or convert it to fat (phosphofructokinase), signals the body that all stores are full. If the glycogen stores are signaled as full, then the third way our body uses excess glucose is to convert it to fatty acids and store as adipose tissue. In essence, fruit sugar is easily converted to fat.

Many may be asking why then is fruit low on the glycemic index? If it does not cause a sudden release of insulin, then how could it ever be a poor food choice? Once the fructose (fruit sugar) enters the liver and liver glycogen is already full, then it can not be used by the muscles for glycogen or energy production. It is converted to fat and released back into the bloodstream to be stored as adipose tissue. The low glycemic response is based on the fact that fructose leaves the liver as fat, and fat does not raise insulin levels.

This is the biochemistry behind the recommendations to limit fruit in your diet. As mentioned, fruit is a very nutritious food full of vitamins, minerals, fiber, and low in calories and fat. If your goal is to exclusively to minimize bodyfat, then it is advisable that you consume more complex carbohydrates, which will go to replenishing muscle glycogen stores rather than fruit, which will only replenish liver glycogen stores, and is useless in muscle glycogen replenishment.

-Patrick Gamboa B.S.
patrick@issaonline.com

References:
1. Costill DL, Sherman WM, Fink WJ, Witten MW, and Miller JM. The role of dietary carbohydrates in muscle glycogen resynthesis after strenuous running. Am. J. Clin. Nutr. 34: 1831-1836, 1981.
2. Shafrir E. Fructose/sucrose metabolism, its physiological and pathological implications. Sugars and Sweeteners, Kretchmer N and Hollenbeck CB, Eds. CRC Press, 1991pp. 63-98.
3. Herbert V, Subak-Sharpe GJ. Total Nutrition: The Only Guide You’ll Ever Need. St Martins Press, 1987 pp. 54-55

[lo zar]

In parole povere, i nostri muscoli hanno la possibilità di immagazzinare tra i 200 e i 450 g di glicogeno (dipende da molti fattori ciò) che servono come saprete, solo per le funzioni che svolgono i muscoli......
Il glicogeno del fegato invece supplisce (concedetemelo) all'energia che occorre a tutto il corpo, anche (anzi soprattutto) una volta che il glicogeno muscolare si esaurisce (o quasi).
Se nel corpo c'è un eccesso di glicogeno e tutto lo stesso "deposito" di glicogeno è full il surplus di zucchero viene convertitò (aihmè) in grasso dal fegato e depositato nel tessuto adiposo.
Saprete anche che i muscoli hanno un limitato numero di enzimi per la sintesi del glicogeno: hanno solo il necessario numero di enzimi per convertire il glucosio in glicogeno

Quindi se il glucosio (gli zuccheri) che assumiamo sono adeguati questi vengono depositati SOLO come glicogeno ( e nn come grasso).....Il muscolo inoltre nn ha i necessari enzimi per convertire il fruttosio in glicogeno; ma è il fegato che sa convertirlo SOLAMENTE come glicogeno epatico. Basterebbero 600ml di un succo di frutta all'arancia("glasses of orange juice")per riempire il glicogeno epatico
Ora assumendo troppi zuccheri ed essendo entrambi i glicogeni (epatico e muscolare) pieni, l'altra via a cui è destinato il glucosio è il tessuto adiposo.....

DVi chiederete: e l'idice glicemico bassissimo del fruttosio?????esso nn causa un rilascio di insulina (il fruttosio è il "pane" infatti dei diabetici)ma entrando SOLAMENTE nel glicogeno epatico ed essendo questo già pieno, NN PUO' ESSERE RIUTILIZZATO DAI MUSCOLI COME GLICOGENO o come energia....per cui.....tac....nel grasso....
L'indice glicemico basso è spiegato "The low glycemic response is based on the fact that fructose leaves the liver as fat, and fat does not raise insulin levels" e " the uptake of fructose into liver cells doesn't require insulin"

[lo zar]

Un altro studiarello

In contrast, one study comparing 75 grams of fructose to 75 grams of glucose, found that, over 4 hours of study, while there was a small amount of de novo lipogenesis from the fructose, the net effect was that the body burned more fat than it produced (30). The fructose group also showed a higher thermic effect (meaning more calories were wasted as heat), most likely because of the high amount of metabolic processing that went on. However, and perhaps more importantly, despite very little fat synthesis in the fructose group, there was less fat burning in that same group. This occurred with an increased burning of carbohydrate in the fructose group.

So it may be that, while fructose at moderate (<50 g/day or so) amounts doesn't increase fat synthesis per se significantly, it may slow fat loss by decreasing fat burning in the liver. That is, to a degree, the end result may be the same: whether the fructose is causing more fat synthesis, or less fat burning, the net effect on fat loss (which is determined by fat burning - fat intake) may be similar.

As I mentioned above, the metabolic fate of fructose appears to depend on the metabolic state of the liver and the dieter. In the fasted state (as occurs while dieting), fructose will be used for energy and fat synthesis will be negligible, if it occurs at all. Fat burning may be decreased however. In the fed state (as occurs when not dieting), excess fructose can be converted to VLDL TG, increasing heart disease risk and bodyfat




Infine vi lascio con la BIOCHIMICA DELLA SINTESI DEL FRUTTOSIO:
(si capisce facilmente su )


in that the liver is the preferred pathway for fructose catabolism. Fructose is phosphorylized by ATP to fructose-1-Phosphate in the liver, then it is hydrolyzed to both dihydroxyacetone Phosphate + Glyceraldehyde (at which point it follows the glycolytic pathway as Glyceraldehyde 3-Phosphate). It is also at a very small degree used for muscle and kidney cells by catalyzation from the hexokinase enzyme by ATP into Fructose-6-phosphate. The liver normally will remove fructose before it gets to these tissues within the body. Because fructolysis provides the liver with excess abundance of pyruvate and lactate, citrate and malate will also increase, which can be used as precursors for fatty acid synthesis and cholesterol synthesis. Dihydroxyacetone phosphate generated by Fructose 1-phosphate aldolase can also be reduced to glycerol-3-phosphate and used for synthesis of glycerolipids such as triacylglycerols, which is an important source of fuel for both the small intestine and the ADIPOSE CELLS.

[Napalm]

Si, l'avevo letto anche io che il fruttosio si tramuta più facilmente in grasso

[Napalm]

Si, l'avevo letto anche io che il fruttosio si tramuta più facilmente in grasso

[MISTER X]

Originally posted by billy_80


non penso proprio che il tofu(formaggio di soia)abbia ig più alto del glucosio. Forse ti riferivi al tofu frozen dessert che peraltro non so nemmeno cosa sia

bye

non sbalgio,basta prendere una qualsiasi tabella dell'ig.

[Zio]

azz' ma che arma a doppio taglio nooooo come risolvere il subdolo uso del fruttosio allora???

ZAR ILLUMINACE

[lo zar]

Originally posted by Zio
azz' ma che arma a doppio taglio nooooo come risolvere il subdolo uso del fruttosio allora???

ZAR ILLUMINACE

NN abusarne........
Il suo utilizzo lo vedrei esclusivamente prima di un work out(fruttosio stesso o frutta in genere).....stop!


Ma okkio soprattutto quando si è in massa........con la già grande quantità di carbo che soi mangiano...
In definizione (sono pochi i carbo in generale) 2-3 frutti al giorno sono ok.....