Ausdauersport & Leistung bei HighFat-Diäten

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    • Ausdauersport & Leistung bei HighFat-Diäten

      Nichts wirklich Neues, stammt aus DiPasquales AD-Buch, aber das kann man ruhig hier mal festhalten:

      Effect of dietary fat on metabolic adjustments to maximal VO2 and endurance in runners.

      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. Expiratory gases and blood responses to a maximum (VO2max) and a prolonged treadmill run were determined following 7 d on each diet. Free fatty acids (FFA), triglycerides, glycerol, glucose, and lactate were measured. Dietary assessment of subjects' N diet indicated that they were consuming approximately 700 kcal.d-1 less than estimated daily expenditures. Running time to exhaustion was greatest after the F diet (91.2 +/- 9.5 min, P < 0.05) as compared with the C (75.8 +/- 7.6 min, P < 0.05) and N (69.3 +/- 7.2 min, P < 0.05) diets. VO2max was also higher on the F diet (66.4 +/- 2.7 ml.kg-1 x min-1, P < 0.05) as compared with the C (59.6 +/- 2.8 ml.kg-1 x min-1, P < 0.05) and N (63.7 +/- 2.6 ml.kg-1 x min-1, P < 0.05) diets. Plasma FFA levels were higher (P < 0.05) and glycerol levels were lower (P < 0.05) during the F diet than during the C and N diets. Other biochemical measures did not differ significantly among diets. 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.
      Quelle: Medicine and Science in Sports and Exercise

      Importance of fat as a support nutrient for energy: metabolism of athletes.

      The two main fuels for muscle metabolism are carbohydrate and fat. There is a limited store of carbohydrate in the body but this is not the case with fat. The average lean man has about 15% of his body weight as fat, whereas the average lean women has about 25% of her body weight as fat. Male and female endurance athletes have only about 7-10% of their body weights as fat. Sedentary people consume diets which contain about 35-40% of their energy intake as fat. The recommended intake of fat in the diet of active and sedentary people is less than that percentage. Although there is a need to increase carbohydrate intake as part of the preparation for heavy training and competition there is no need to supplement the normal diet with additional fat. Fat is mobilized from adipose tissue in response to stimulation of an intracellular lipase by the catecholamines. The products of the hydrolysis of triglycerides, the storage form of fat, are fatty acids and glycerol. The 'free' fatty acids are transported to muscle in loose combination with plasma albumin where they are released and taken up and oxidized. Glycerol is not used directly as a substrate but undergoes gluconeogenesis in the liver. This process helps restock liver glycogen stores which, in turn, provides glucose as a fuel for the central nervous system and for muscle metabolism. Training increases the capacity of skeletal muscles to use fat as an energy source. An increase in fat metabolism during prolonged exercise has a glycogen sparing effect and as such improves endurance capacity.
      Quelle: Journal of Sport Sciences

      Glycogen repletion and exercise endurance in rats adapted to a high fat diet.

      It is well accepted that exercise endurance is directly related to the amount of carbohydrate stored in muscle and that a low carbohydrate diet reduces glycogen storage and exercise performance. However, more recent evidence has shown that when the organism adapts to a high fat diet endurance is not hindered. The present study was designed to test that claim and to further determine if animals adapted to a high fat diet could recover from exhausting exercise and exercise again in spite of carbohydrate deprivation. Fat-adapted (3 to 4 weeks, 78% fat, 1% carbohydrates) rats (FAT) ran (28 m/min, 10% grade) as long as carbohydrate-fed (69% carbohydrates) animals (CHO) (115 v 109 minutes, respectively) in spite of lower pre-exercise glycogen levels in red vastus muscle (36 v 54 mumols/g) and liver (164 v 313 mumols/g) in the FAT group. Following 72 hours of recovery on the FAT diet, glycogen in muscle had replenished to 42 mumols/g (v 52 for CHO) and liver glycogen to 238 mumols/g (v 335 for CHO). The animals were run to exhaustion a second time and run times were again similar (122 v 132 minutes FAT v CHO). When diets were switched after run 1, FAT-adapted animals, which received carbohydrates for 72 hours, restored muscle and liver glycogen (48 and 343 mumols/g, respectively) and then ran longer (144 minutes) than CHO-adapted animals (104 minutes) that ate fat for 72 hours and that had reduced glycogen repletion. We conclude that, in contrast to the classic CHO loading studies in humans that involved acute (72 hours) fat feedings and subsequently reduced endurance, rats adapted to a high fat diet do not have a decrease in endurance capacity even after recovery from previous exhausting work bouts. Part of this adaptation may involve the increased storage and utilization of intramuscular triglycerides (TG) as observed in the present experiment.
      Quelle: Metabolism: Clinical and Experimental.

      Role of lipids on endurance capacity in man.

      A man whose weight is near 70 kg has approximately 15 kg of fat as triglycerides in adipose tissue, representing about 140,000 kcal. With such a quantity of stored fat, the question is to know why triglycerides are not the only fuel for exercise. Probably because this fuel cannot sustain maximal rates of exercise. The ability to sustain maximal exercise is dependent on carbohydrate use. The reason for the limited rate at which energy can be derived from fat store is not clear. We can examine successively: 1) The rate of release from adipose tissue. Hydrolysis of the adipose tissue triglyceride is regulated by hormonal and nervous influence. It has recently been shown that 70% of fatty acids released from adipose tissue at rest are reesterified. This value decreases to 25% at the onset of submaximal exercise at 40% of VO2max. One part of the increase in fat oxidation could therefore result from the reduced reesterification. 2) The capacity of transport and muscle extraction. A close correlation has been shown between the increase in FFA concentration and FFA uptake during increased energy expenditure under the effect of exercise. Exercise increases lipoprotein lipase (LPL) activity in muscle. This causes increase in muscle and cardiac FFA uptake and a decrease in LPL activity in adipose tissue. The control of this enzyme is coordinated by hormonal mechanisms resulting from the reduction of insulin and the increase in catecholamines induced by exercise.
      Quelle: International Journal of Sport Medicine

      Letzte Studie impliziert, dass die Fettverbrennung bei höherer Belastung deswegen zurückgeht, weil die Muskeln dazu übergehen, eher die intrazellulären Fettspeicher (Triglyceride) anzuzapfen und folglich gar nicht so sehr auf das Depotfett angeweisen sind
      "Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." - Antoine de Saint-Exupery
    • Re: Ausdauersport & Leistung bei HighFat-Diäten

      Bezüglich der letzten Studie habe ich einige Verständnisprobleme.

      Passend dazu habe ich gerade ausführlich diese Studie gelesen:

      jci.org/articles/view/30566

      Nach dem Training steigt nicht nur die Aufnahmefähigkeit an Triglyzeriden in der Muskulatur an, sondern auch die Verwertung von diesem Energielieferanten. Ebenfalls verhindert/reduziert das Training die Möglichkeit, Fett überhaupt erst in Fettzellen zu speichern.

      Um mein Verständnis etwas auszuweiten. Steigt die Syntheserate von Fettenergie in Muskulatur aber sinkt die Abgabemöglichkeit im Fettgewebe und als Zusatz konsumiere ich keinerlei Essen, woher bekommt dann auf Dauer mein Muskel Energie?

      Als Zusatz: Die durch das Training erhöhte Fettverstoffwechslung im Muskel ermöglicht auch bei einer sehr fettreichen Ernährung eine 1:1 Fettaufnahme:Oxidation.

      ncbi.nlm.nih.gov/pubmed/9316454
    • Re: Ausdauersport & Leistung bei HighFat-Diäten

      Ist natürlich eine berechtigte Frage. Ein Teil der Energie wird ja sicher auch wieder zurückgewonnen (Laktat/Pyruvat usw. usf.). So wie ich das sehe, kommt ja Energie durch FFA-Freisetzung, nur nicht in so großem Umfang. Es zirkulieren ja sicherlich auch weiterhin FFA im Blut und werden zum Muskel transportiert (die Wahrscheinlichkeit der re-esterfication dürfte damit tendenziell sinken). Auch bei einer keto-adapted Situation dürftest du bei größerem Defizit Energie aus Protein gedeckt haben. Dennoch dürfte das Hauptsubstrat in Form von Fett daherkommen (und bisschen Glukose, die bei dem Abbau der Triglyceride frei wird).

      Nagel mich aber auf den Spekulationen nicht fest. :hippie:
      "Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away." - Antoine de Saint-Exupery
    • Re: Ausdauersport & Leistung bei HighFat-Diäten

      Mmhmh. Ein sehr interessantes Thema. Erst mal vielen Dank für deine Gedanken. Unabhängig der aktuellen Diskussion zeigen auf jeden Fall Training positive Auswirkungen auf die Verstoffwechselung von Fett in Muskulatur. Dass natürlich erst mal durch das erhöhte Vorhandensein von LPL in Muskelzellen mehr Triglyzeride aus dem Blut gezogen werden, ist sehr schön. Dass sich die Speicherfähigkeit erhöht, noch besser. Dass sich die Verstoffwechselung von Fett erhöht auch. Dass die Fettspeicherung in Fettzellen verkleinert wird, ist auch top.