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mikaelj wrote:Jag vet inte om det är en lågkolhydratdiet eller enbart högprotein, men [http://www.second-opinions.co.uk/fat-not-protein.html Why Low-Carb Diets Must Be High-Fat, Not High-Protein] kan vara intressant. Annars låter din kosthållning som ett perfekt sätt att få rabbit starvation.
Du får inte Rabbit Starvation av den termogena dieten.
Rabbit starvation bygger på att det finns en begränsning i hur mycket urea som kan produceras av levern från kvävet i proteinet och när den begränsningen är nådd så skulle det i så fall leda till hyperammonemi och hyperaminoacidemia.
Den teoretiska gränsen ligger på (som bla baseras på en studie: Rudman, D, T.J. DiFulco, J.T. Galambos, R.B. 3rd Smith, A.A. Salam, and W.D. Warren.
Maximal rates of excretion and synthesis of urea in normal and cirrhotic subjects. J.Clin. Invest. 52:2241-2249, 1973.) 3,5-4,5g protein/kg kroppsvikt innan man skulle få problem.Dock så är säkerligen människokroppen så anpassningsbar att man klarar av högre proteinmängder vilket många kroppsbyggare gör som t ex Kjellström som ligger uppåt 1kg protein under vissa perioder vilket på hans kroppsvikt blir runt 7g protein/kg kroppsvikt.
Finns även studier som visar på att vissa djur vid ökat proteinintag uppreglerar vissa av de enzymer i levern som är involverade i metabolismen av aminosyror.
Quote:Amino acid catabolism must occur in a way that does not elevate blood ammonia (26). Catabolism of amino acids occurs in the liver, which contains the urea cycle (26), however the rate of conversion of amino acid derived ammonia to urea is limited. Rudman et al. (27) found that the maximal rate of urea excretion (MRUE) in healthy individuals was 55 mg urea N ∙ h-1 ∙ kg-0.75, which is reached at an intake level of 0.53 g protein N/kg-0.75 At higher protein intakes there is no further increase in urea excretion rate, but a prolongation of the duration of MRUE, often in excess
of 24 h (27).
In a further investigation of the fate of protein nitrogen, Rudman et al. (27)
were able to quantify the temporary accumulation of urea in body water during MRUE and the amount hydrolyzed in the gastrointestinal tract. Subsequently an algorithm was developed to estimate the capacity of the liver to deaminate amino acids and produce urea, termed the maximal rate of urea synthesis (MRUS). In a study on 10 healthy subjects, the MRUS averaged 65 mg urea N ∙ h-1 ∙ kg0.75 (with a range of 55 to 76). Thus the level of dietary protein that can be deaminated and
processed through to urea by the liver in a 24-h period is dependent on body weight and individual variation in efficiency of the process, as indicated in Table 1. An 80 kg individual, for instance, could deaminate up to 301 g protein per day, but may be limited to 221 g protein per day, given the range in MRUS determined by Rudman et al. (27). However, the safe intake level of protein consumption may even be slightly higher than these figures, as not all protein is deaminated and converted to urea. A certain amount of protein as indicated by the RDA is used directly for structural/functional purposes, including bone and soft tissue growth, maintenance and repair plus production of hormones, antibodies, and enzymes, thus not requiring deamination.
The US recommended dietary allowance (RDA) of 0.8 g ∙ kg-1 ∙ d-1 (28), set
this level of necessary protein intake for structural requirements to cover the needs of 97.5% of the population. Adding this protein requirement (64 g/d for an 80 kg individual) to the level of protein that can be converted to urea, yields a theoretical maximal daily protein intake based on body weight and efficiency of urea synthesis in individuals. An 80 kg individual, for example, could theoretically tolerate 325 g protein per day (range 285 to 365 g) without showing symptoms of hyperammonemia and hyperaminoacidemia. Such levels are certainly not advocated by the authors and no practical rationale exists for such elevated protein intakes. In fact, common sense would even dictate that we accept the lower end of the range as the
maximum safe intake levels, to allow for individuals with reduced MRUS. Hence, for an 80 kg individual, 285 g protein per day should be viewed as an absolute maximum. Even this amount would be equivalent to the consumption of approximately 1 kg of lean meat per day. A more realistic intake of approximately half this amount would contribute approximately 60 g protein to structural needs and a further approximately 80 g to bodily energy needs, either directly, through gluconeogenesis or as stored fat. The advantage being that this protein could displace fat or carbohydrate from the diet, increase satiety (plus yield less energy due to its higher rate of thermogenesis) thus helping in weight control, a controversial but promising area of research and will be discussed later. It may be prudent to point out, however, that the given range of MRUS determined by Rudman et al. 27), had significant limitations, as it consisted of a small sample size (10 normal and 34 cirrhotic subjects), excluded individual differences according to age, sex, previous diet history, training status, and was undertaken more than 30 y ago. The dangers of excessive protein intake should not be underestimated and have been recognized historically through the excess consumption of lean wild meat by early American explorers leading to a condition referred to as “rabbit starvation syndrome,” in which symptoms included nausea and diarrhea followed by death within 2 to 3 wk (29). This syndrome was explained as the inability of the human liver to sufficiently upregulate urea synthesis to meet “large” loads of protein (29). Some studies have shown animals can adapt to a high protein diet by upregulating amino acid metabolizing enzymes such as alanine and aspartate aminotransferases, glutamate dehydrogenase, and argininosuccinate synthetase (30), and increase mitochondrial glutamine hydrolysis in hepatocytes (31). Other studies, however, show that when animals are faced with large protein loads, the rate of gastric emptying is reduced as the catabolic and anabolic systems of the body become saturated, unable to deal with an excess of dietary nitrogen under acute conditions (32). This reduction in rate of gastric emptying subsequent to an elevated dietary protein intake suggests the presence of regulation at the gastric step to ensure the catabolic capacities of the liver are not exceeded (33). This negative feedback on stomach emptying rate and food intake could be affiliated with chemical, biochemical, and/or physical signals translated by the vagus nerve (34, 35). To what degree do these processes transpire in humans, and at what threshold intake of protein is currently unknown as very little data have been collected on humans consuming high protein diets for prolonged periods of time. The one well known case is that of the early 20th century Arctic explorer Vilhjalmur Stefansson, who after many years living with the Arctic Inuit and consuming a diet estimated to be approximately 50% energy as protein, returned to civilization and conducted a year-long experiment on himself at Bellevue Hospital in New York. During this time, Stefansson, a fit 72.5 kg man, consumed meat only, with a variable protein:fat ratio. During the first 3 d he became ill with the symptoms of “rabbit starvation” at a protein intake of 264 g/d, which was 45.3% of his energy intake (36). As the protein level was lowered slightly and replaced with extra fat, however, on the fourth and fifth days symptoms disappeared. This level of protein intake may have been sustainable if hepatic enzymes were given time to upregulate (as there were several years between Stefansson living with the Inuit and the experiment at Bellevue Hospital and any previous upregulation of hepatic enzymes would have diminished), but the result for this limited study (where n = 1) indicates that the values shown in Table 1 are at least realistic, although we would speculate that individuals would tend to be at the lower end of the range for MRUS without a lead-in time for upregulating hepatic enzyme function.A Review of Issues of Dietary Protein Intake in Humans
International Journal of Sport Nutrition and Exercise Metabolism, 2006, 16, 129-152Fabrice wrote:Köp ett gott kaseinpulver. Kesella är ganska dyrt faktiskt. billigare med ägg och ful-tonfisk:) Kyckling är nog med billigare än kvarg.. tror jag. Men ska man köra en termogen diet så måste man nästan gå på med proteintillskott. Enbart vanlig mat är det svårt att komma över 250 gram protein tycker jagjag äter 35g kassein/vassle / dag under min termogena diet. Resten solid föda så håller man sig mätt :up:
garm wrote:jag äter 35g kassein/vassle / dag under min termogena diet. Resten solid föda så håller man sig mätt :up:det blir dyrt tycker jag med tanke på hur lite fett man ska få i sig. 45 gram eller har jag fel?
Jonte91 wrote:Låter som att du käkar lite för mkt protein:PHela poängen är ju den att trådskaparen inte når upp till önskad mängd protein. Visst är proteinintaget högt men det är ju den här dietens syfte och eftersom det trots allt inte är skadliga mängder tycker jag inte direkt man kan kritisera det.
Men jag ser dock ingen anledning att oroa sig på det sättet nnnn4 gör och att inte ens kunna lägga sig för att proteinintaget inte nått önskad dagsmängd är ju direkt skrämmande att läsa.
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