Dec 15, 2008

Health - Cut the calories, not the carbs

Sanchita Sharma

No nutrition textbook would list potatoes among brain foods, but it seems this diet-derailer has something going for it. Apart from adding inches to the waist, potatoes and other carb-rich foods also give the brain the fillip it needs to function well.

Cognitive tests of dieters show that those on no-carb diets do badly on memory-based tasks compared to those who reduce their calorie intake but have carbohydrates, reports a US study. The effect, however, is temporary and when carbs are put back in the plate, brain and memory function gets back to normal.

Also, the longer the body does without carbs, the greater is the impact on brain function.

The reason for memory failing, say nutritionists, is that the brain uses glucose as its primary fuel but has no place to store it. It has to wait for the body to break down carbohydrates into glucose. This glucose is then carried to the brain in the bloodstream, from where it is quickly lapped up by nerve cells for functioning. Reduced carbohydrate intake lowers this source of instant energy, affecting brain function.

“The food you eat can have an immediate impact on cognitive behaviour. The popular low-carb, no-carb diets have the
strongest potential for negative impact on thinking and cognition,” said the author of the study, Dr Holly A. Taylor, professor of psychology at Tufts University in Boston (“Low-carbohydrate weight-loss diets. Effects on cognition and mood”, Appetite, February 2009).

Low-carb plans became a vogue in the late-80s when diet guru Robert Atkins theorised that it is not fat that made you fat, but sugar and carbohydrates. He made a fortune selling his high protein-no-carb diet to weight-watchers and by the early-90s, potatoes, breads and pastas had gone off many restaurant menus and dinner tables. When he died of a heart attack caused, say critics, by grease-clogged arteries, his wonder plan got somewhat tarnished, but it still has followers among people seeking to lose weight quickly.

New nutritional wisdom insists that except for saturated- and trans-fats, there are no bad foods groups, only bad portions.

If you cut back on the amount you eat, unwanted body fat will stay away. (To avoid bad fats, stay away from fats that solidify at room temperature, though a bit of ghee is fine as it contains 40 per cent heart-healthy mono-unsaturated fat).

So don’t zealously follow simplistic diet plans that ask you to stop eating one or more food groups completely. Have smaller portions of everything instead. Diet gurus can argue about which diet to follow to limit those calories — high-protein, low-fat, low-carb, a mixture — but the bottom line is the same: cut the calories.

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