Newsgroup: it.salute.alimentazione
Titolo: % Grassi e % carboidrati negli sport di endurance

Sinceramente credevo che l'affermazione secondo cui l'alimentazione
negli sport di endurance DEVE prevedere che la max percentuale di
introito calorico provenga dai carboidrati non fosse stata ancora
messa fortemente in discussione dai nutrizionisti "ufficiali".
Invece, sguazzando a caso su PUBMED, ho trovato numerosi articoli
degli ultimi anni che mettono a confronto diete ad alto contenuto
energetico proveniente dai carboidrati con diete ad alto contenuto
energetico dai grassi...
Dando un'occhiata a vari abstract, dei quali ne riporto alcuni, sono
rimasto sorpreso: l'ipotesi di high fat diets negli sport di endurance
è presa SERIAMENTE in considerazione, specie quando gli atleti sono
sottoposti ad un periodo di adattamento...
Ciao!
Gianni
----------------------------------------
A perspective on fat intake in athletes.
Pendergast DR, Leddy JJ, Venkatraman JT.
Department of Physiology and Biophysics, School of Medicine and
Biomedical Sciences, Buffalo, New York 14214, USA.
Performance in endurance events is dependent upon the maximal aerobic
power, the percentage of that power that can be sustained and the
availability of substrates (carbohydrates [CHO] and fats). The purpose
of this paper is to present a perspective of recent studies that
demonstrate the role of fat intake and oxidation on endurance
performance.
..........
Based on this review, a baseline diet comprising 20% protein, 30% CHO
and 30% fat, with the remaining 20% of the calories distributed
between CHO and fat based on the intensity and duration of the sport,
is recommended for discussion and future research.
-------------------------------
Effects of high-fat and high-carbohydrate diets on metabolism and
performance in cycling.
Rowlands DS, Hopkins WG. School of Physical Education and Department
of Physiology, University of Otago, Dunedin, New Zealand.
We compared the effects of high-fat and high-carbohydrate dietary
conditions on metabolism and short- and ultra-endurance cycling
performance.
.......
In conclusion, high-fat dietary conditioning increased fat oxidation,
and although the main effects were not statistically significant,
there was some evidence for enhanced ultra-endurance cycling
performance relative to high-carbohydrate. Copyright 2002, Elsevier
Science (USA). All rights reserved.
-----------------------------
High-carbohydrate versus high-fat diets: effect on body composition in
trained cyclists.
Brown RC, Cox CM, Goulding A.
Department of Human Nutrition, University of Otago, Dunedin, New
Zealand. 
rachel...@stonebow.otago.ac.nz
PURPOSE: Recent research suggesting the benefits of high-fat diets for
endurance athletes have been viewed with caution because of the
potential negative health consequences, including increased adiposity.
.......
In conclusion, during periods of endurance training when energy
requirements are high, increasing the percentage of fat in the diet to
approximately 50% of total energy does not increase body weight or
adiposity because athletes are able to maintain energy balance.
-----------------------------
Enhanced endurance in trained cyclists during moderate intensity
exercise following 2 weeks adaptation to a high fat diet.
Lambert EV, Speechly DP, Dennis SC, Noakes TD.
Liberty Life Chair of Exercise and Sports Science, University of Cape
Town Medical School, Observatory, South Africa.
These studies investigated the effects of 2 weeks of either a high-fat
(HIGH-FAT: 70% fat, 7% CHO) or a high-carbohydrate (HIGH-CHO: 74% CHO,
12% fat) diet on exercise performance in trained cyclists...
....
Exercise time to exhaustion during HIE was not significantly different
between trials: nor were the rates of muscle glycogen utilization
during HIE different between trials, although starting muscle glycogen
content was lower [68.1 (SEM 3.9) vs 120.6 (SEM 3.8) mmol.kg-1 wet
mass, P < 0.01] after the HIGH-FAT diet.
Despite a lower muscle glycogen content at the onset of MIE [32 (SEM
7) vs 73 (SEM 6) mmol.kg-1 wet mass, HIGH-FAT vs HIGH-CHO, P < 0.01],
exercise time to exhaustion during subsequent MIE was significantly
longer after the HIGH-FAT diet......
 
-------------------------------------
Dietary fats and immune status in athletes: clinical implications.
Venkatraman JT, Leddy J, Pendergast D.
Department of Physical Therapy, Exercise and Nutrition Sciences,
Sports Medicine Institute, University at Buffalo, NY 14214, USA.
j...@acsu.buffalo.edu
Athletes are competitive, train at very high levels with inadequate
rest, consume too few calories, avoid fats, and may be at increased
risk of infections.
....
Increasing the dietary fat intake of athletes to 42%, while
maintaining caloric intake equal to expenditure, does not negatively
affect immune competency or blood lipoproteins, whereas it improves
endurance exercise performance at 60-80% of VO2max in cyclists,
soldiers, and runners.
------------------------
Effect of dietary fat on metabolic adjustments to maximal VO2 and
endurance in runners.
Muoio DM, Leddy JJ, Horvath PJ, Awad AB, Pendergast DR.
Department of Physiology, State University of New York at Buffalo,
School of Medicine and Biomedical Sciences 14214.
The present study examined the effects of dietary manipulations on six
trained runners. The percent energy contributions from carbohydrate,
fat, and protein were 61/24/14, 50/38/12, and 73/15/12 for the normal
(N), fat (F), and carbohydrate (C) diets, respectively.
.......
These data suggest that increased availability of FFA, consequent to
the F diet, may provide for enhanced oxidative potential as evidenced
by an increase in VO2max and running time. This implies that
restriction of dietary fat may be detrimental to endurance
performance.
-----------------------------------
The human metabolic response to chronic ketosis without caloric
restriction: preservation of submaximal exercise capability with
reduced carbohydrate oxidation.
Phinney SD, Bistrian BR, Evans WJ, Gervino E, Blackburn GL.
To study the effect of chronic ketosis on exercise performance in
endurance-trained humans, five well-trained cyclists were fed a
eucaloric balanced diet (EBD) for one week providing 35-50 kcal/kg/d,
1.75 g protein/kg/d and the remainder of kilocalories as two-thirds
carbohydrate (CHO) and one-third fat. This was followed by four weeks
of a eucaloric ketogenic diet (EKD), isocaloric and isonitrogenous
with the EBD but providing less than 20 g CHO daily.
...............
These results indicate that aerobic endurance exercise by well-trained
cyclists was not compromised by four weeks of ketosis. This was
accomplished by a dramatic physiologic adaptation that conserved
limited carbohydrate stores (both glucose and muscle glycogen) and
made fat the predominant muscle substrate at this submaximal power
level.
------------------------------
Effects of high fat versus high carbohydrate diets on plasma lipids
and lipoproteins in endurance athletes.
Brown RC, Cox CM.
Department of Human Nutrition, University of Otago, Dunedin, New
Zealand. 
rachel...@stonebow.otago.ac.nz
Recent research suggesting the performance benefits of high fat diets
for endurance athletes have been viewed with caution because of the
potential negative health consequences, including increased coronary
heart disease risk.
.............
During periods of endurance training when energy requirements are
high, increasing the percentage of fat in the diet to approximately
50% of total energy did not result in adverse changes to the plasma
lipoprotein profiles of this group of athletes.

 Gianni
siamo alle solite , tutti smentiscono tutto e tutti
e per gi ignoranti come me diventa sempre + difficile
capirci....qualcosa...
cmq. io non sono al corrente di maratoneti che seguono quei tipi di regimi
alimentari
rusca

 lipoprotein profiles of this group of athletes.
ok è molto confortante, ma rimane il fatto che non riesco a capire a che
tipo di grassi/alimenti è più salutare affidarsi per evitare troppi carbo.
Quello che vorrei sapere in parole povere è se è bene evitare di mangiare
7/8 pesche o un melone intero per mangiarsi invece del un pollo allo spiedo
con tanto di pelle oppure per mangiarsi un po' più di frutta secca e del
petto di pollo come faccio adesso?
cesare

 tipo di grassi/alimenti è più salutare affidarsi per evitare troppi carbo.
Secondo me è chiaro che con i grassi monoinsaturi non si può sbagliare.
La Harvard school afferma che non esistono evidenze per limitare la % di
energia proveniente dai grassi a qualche valore "ottimale".
"Many health agencies, including the American Dietetic Association,
the American Diabetes Association, and the American Heart Association,
recommend limiting fat intake to 30% or less of total daily calories as a
means of preventing disease.
However, there is no good evidence for any particular "optimal" amount of
total fat in a healthy diet. "
http://www.hsph.harvard.edu/nutritionsource/fats.html
Sui grassi saturi ci sono opinioni contrastanti.
Ad esempio alcuni assertori delle diete moderate in carboidrati affermano
che i grassi saturi fanno male e sono molto presenti in animali
che vengono alimentati con cereali per lo stesso motivo per cui si
accumulano negli uomini che mangiano troppi carboidrati.
L'uomo paleolitico mangiava carni magre di animali selvatici, a lora volta
nutriti in modo naturale...
Che ne pensa il buon vecchio Xlater?
Ciao!
Gianni

 petto di pollo come faccio adesso?
Non esiste ragione al mondo per limitarsi a mangiare carni magre.
Ti privi di ottimi macro e micronutrienti, oltre che del piacere
del mangiare.
Xlater
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 alla Xlater"? Ti giuro che non lo so.
se praticamente non mangi carbo e come dice GP max 2 gr di proteine per kg
allora significa che stai in piedi quasi esclusivamente con i grassi?
cesare

 wrote in message
news:cf04rk$8fe$
1...@domitilla.aioe.org
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Stai usando il "tu" etico o ti riferisci a me?
Sto molto sotto i 2gr di proteine per kg di peso corporeo. Non raggiungo
nemmeno l'1,5. E soprattutto non sono abituato ad esprimermi per
percentuali, perché non credo che abbia senso.
Quanto ai carbo, 60-70gr al giorno sono una quantità di tutto rispetto.
