kalle_banan
2009-08-18, 11:00
Artikeln: http://well.blogs.nytimes.com/2009/08/13/fatty-foods-affect-memory-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/abstract/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.
[...] 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/abstract/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.