Högfettdiet leder till sämre korttidsminne och fysisk prestation

[kalle_banan]

Artikeln: http://well.blogs.nytimes.com/2009/0...-and-exercise/

[...] Although the human data aren’t yet published, the researchers have also performed similar studies of high-fat diets in healthy young men who then performed exercise and cognitive tests. Dr. Murray said he is still reviewing the data, but the short-term effect of a fatty diet on humans appears to be similar to that found in the rat studies.
It’s not clear why fatty foods would cause a short-term decline in cognitive function. One theory is that a high-fat diet can trigger insulin resistance, which means the body becomes less efficient at using the glucose, or blood sugar, so important to brain function.

Fatty foods appear to have a short-term effect on exercise performance because the body reacts to high fat content in the blood by releasing certain proteins that essentially make the metabolism less efficient. “It’s thought to be a protective mechanism to get rid of excess fat,’’ Dr. Murray said. “But it was making muscles less efficient at using oxygen and fuel to make the energy needed to run.’’

The findings are particularly relevant to people who may not worry about binging on fatty foods because they exercise regularly.

“Exercise is a good way of burning it off, because you’re burning the calories off,’’ Dr. Murray said. “But in terms of actually trying to put in a good time if you’re running, it will limit your performance.’’

Studien: http://www.fasebj.org/cgi/content/ab...fj.09-139691v1

Efficiency, defined as the amount of work produced for a given amount of oxygen consumed, is a key determinant of endurance capacity, and can be altered by metabolic substrate supply, in that fatty acid oxidation is less efficient than glucose oxidation. It is unclear, however, whether consumption of a high-fat diet would be detrimental or beneficial for endurance capacity, due to purported glycogen-sparing properties. In addition, a high-fat diet over several months leads to cognitive impairment. Here, we tested the hypothesis that short-term ingestion of a high-fat diet (55% kcal from fat) would impair exercise capacity and cognitive function in rats, compared with a control chow diet (7.5% kcal from fat) via mitochondrial uncoupling and energy deprivation. We found that rats ran 35% less far on a treadmill and showed cognitive impairment in a maze test with 9 d of high-fat feeding, with respiratory uncoupling in skeletal muscle mitochondria, associated with increased uncoupling protein (UCP3) levels. Our results suggest that high-fat feeding, even over short periods of time, alters skeletal muscle UCP3 expression, affecting energy production and physical performance. Optimization of nutrition to maximize the efficiency of mitochondrial ATP production could improve energetics in athletes and patients with metabolic abnormalities.—Murray, A. J., Knight, N. S., Cochlin, L. E., McAleese, S., Deacon, R. M. J., Rawlins, J. N. P., Clarke, K. Deterioration of physical performance and cognitive function in rats with short-term high-fat feeding.

[Doctor Snuggles]

...hos råttor.

[stafh]

Ursprungligen postat av Doctor Snuggles

...hos råttor.

"Although the human data aren’t yet published, the researchers have also performed similar studies of high-fat diets in healthy young men who then performed exercise and cognitive tests. Dr. Murray said he is still reviewing the data, but the short-term effect of a fatty diet on humans appears to be similar to that found in the rat studies."

[Doctor Snuggles]

Ursprungligen postat av stafh

"Although the human data aren’t yet published, the researchers have also performed similar studies of high-fat diets in healthy young men who then performed exercise and cognitive tests. Dr. Murray said he is still reviewing the data, but the short-term effect of a fatty diet on humans appears to be similar to that found in the rat studies."

Då får man vänta tills de publicerat de studierna då innan man kan uttala sig.

[mikaelj]

*gäsp*

Jag höjer med sund.nu: Low carb dieter ger sämre minne och tankekraft och synar.

[Apos78]

Ursprungligen postat av Doctor Snuggles

Då får man vänta tills de publicerat de studierna då innan man kan uttala sig.

Uttala sig kan man alltid göra. Dock med en viss försiktighet.

[stafh]

Ursprungligen postat av Doctor Snuggles

Då får man vänta tills de publicerat de studierna då innan man kan uttala sig.

"appears to be similar" är väl ett ganska blygsamt och försiktigt uttalande?

[Eddie Vedder]

Det är ju knapppast ovanligt att personer rapporterar sämre koncentration och ork i inledningen av en kostomläggning med reducerat kolhydratintag. Så det känns ju logiskt, men inget säger ju mer än just 9 dagar även om man nu antar att råttor och människor är så lika.

[Apos78]

Ursprungligen postat av Eddie Vedder

Det är ju knapppast ovanligt att personer rapporterar sämre koncentration och ork i inledningen av en kostomläggning med reducerat kolhydratintag. Så det känns ju logiskt, men inget säger ju mer än just 9 dagar även om man nu antar att råttor och människor är så lika.

Och då kopplas detta till just det begränsade intaget av kolhydrater. Är detta något författarna till den aktuella studien på något sätt justerat för tro i deras slutsats att det istället kanske beror på det höga fettintaget? Att ett högt fettintag triggar en insulinresistens är en hypotes men samma effekt kommer om kolhydraterna helt enkelt inte är tillgängliga. Vilket jag antar hittills varit den förklarande faktorn gällande en sådan diet och kognition.