Fat pills have no weight_英文原版

herbal supplements designed to help shed weight are virtually ineffective because they cannot beat the body's efforts to conserve fat, an obesity expert claims.

new zealand academic and doctor anne-thea mcgill has told the international congress on obesity in sydney that the modern diet is lacking in nutrients.

most humans eat an energy-dense western diet of processed foods which have had many of the micronutrients removed, dr mcgill said.

"we used to get enough micronutrients from past diets high in fruit, vegetables, fibre and lean protein, but with our current diet we don't,'' she said.

on top of this, human metabolism appears to have "turned off'' the processes to make many vitamins to save energy for the complex brain to use.

the university of auckland researcher said this combination of too much processed food, excess energy and micronutrient deficiency produces a state of malnutrition.

in the face of nutritional stress, the body predicts tough times and adapts by creating fat stores.

"the body reacts to the famine stress by storing fat around the upper body,'' dr mcgill said.

people who struggle with their weight are often enticed into buying over the counter vitamins and herbal remedies to help shed their kilograms.

but dr mcgill said such concoctions had not been effectively tested in large-scale medical trials and were virtually ineffective in the face of the body's 'famine'.

"many over-the-counter remedies such as concentrated herbal preparations, food extracts, minerals and vitamins were promoted as helping to decrease body weight,'' dr mcgill said.

"however, they do not redress the nutrient imbalance from poor diets that produce obesity.''

many of the agents - namely garlic, soya, amino acids, vitamins, fibres and minerals that were found in over-the-counter weight loss products - would be more effective for weight loss when consumed in food in their natural form, dr mcgill said.

she said supplements, beyond being ineffective, could even produce serious adverse effects if taken in large doses.

for example, large doses of beta carotene had been associated with an increased risk of lung cancer in smokers and studies giving vitamin e in people with cardiovascular disease had been shown to increase risk of heart failure, the doctor said.