From Ergo Log
Burning a couple of hundred kcal extra a day by exercising more is a great way to lose weight. Reducing the amount of carbohydrates in your food is another good way to lose weight. It’s a shame you can’t combine the two – because if you’ve got a low blood sugar level your muscles can’t perform well and you can forget doing exercise. Or not? Nutritionists at the University of South Australia have a different view of the matter.
No, a low-carbohydrate diet isn’t necessarily the only way to lose weight, and yes, low-carb weight loss is fine.
Many trainers are not at all in favour of low-carbohydrate eating patterns. Athletes need carbs, they say. Without glucose athletes don’t have the energy to train. And trainers say this not because they are stupid, but because they listened carefully when they did their training course. It’s still in textbooks and course material – and all the information is based on good scientific research.
The researchers at the University of New South Wales took another good look at the effect of aerobic training on pain tolerance. They got a dozen students to cycle at One disadvantage to these studies is that they are all of short duration. In practice, a body that’s used to a high-carb diet needs a few days – and sometimes even a few weeks – to get used to a diet in which the energy is derived mostly from fats and proteins.
The Australians wanted to describe the long-term effects of a low-carb diet on performance capacity, so they put a group of about twenty overweight adults on a low-carb diet for a year [LC]. An equal-sized control group got a high-carb diet [HC]. Both low-carb and high-carb diet provided the subjects with a couple of hundred calories less than they burned.
After a year both groups had lost about the same amount of fat. The differences between the two groups were not significant.
During the year that the study lasted the subjects did not do any extra sport. Before they started the diet and at the end the researchers tested their physical condition on a treadmill and measured their muscle strength. The weight loss made the subjects in both groups a little fitter; both groups performed equally well.
The people on the low-carb diet burned more fat during moderately intensive exercise on the treadmill. The high-carb diet had the opposite effect. The difference between the effect of the low-carb and the high-carb diet was statistically different.
The subjects in both groups burned the same number of kcals on the treadmill.
“Compared to a high carb diet, long-term consumption of a low carb diet did not impair exercise tolerance or exercise capacity in overweight and obese individuals”, the researchers conclude. “A low carb diet shifted fuel utilization during submaximal exercise to favor fat oxidation with no effect on rating of perceived exertion. Overall, these data suggest that compared to a high carb diet, prolonged consumption of an low carb weight loss diet should not impact adversely on physical function or the ability to perform exercise.”
J Am Coll Nutr. 2014 Jul 2:1-7. [Epub ahead of print].