London: Here`s a bit of advice – it is better to avoid putting on weight in the first place, for a new study says that once you are overweight you will stay that way no matter how hard you try.
Researchers have found that the majority of overweight or obese people who try to lose shed flab by cutting calories or exercising will return to their former size.
The 55-year study of 25,000 people, by the Medical Research Council`s National Survey of Health and Development, has shown that once people gain weight and then go on a diet, their body almost always returns to its original size.
For their study, the researchers followed 5,362 men and women from their birth in 1946 and 20,000 from birth in 1958, measuring their weight and blood pressure and assessing their lifestyles.
They found both groups began gaining weight in the 1980s and have steadily increased in size ever since, the `Daily Mail` reported.
Dr Rebecca Hardy, the council`s programme leader on body size, said: "Once people become overweight, they continue relentlessly upwards. They hardly ever go back down. A few lose weight but very few get back to normal. The best policy is to prevent people becoming overweight.
"For men (weight) goes up steadily through life. For women it starts slowly and accelerates in the mid-30s. Once people become overweight they continue relentlessly upwards -- hardly ever going down. The best policy is preventing people becoming overweight."
But the study`s findings don`t mean that dieting is pointless as eating less and taking more exercise can increase fitness and lower blood pressure, say the researchers.
Prof Nick Finer of University College London Hospital, suggests evolution is to blame for the difficulty in losing weight. "It`s unlikely man would have evolved with mechanisms to counter obesity -- only a problem in last 30 to 40 years. For most of history, storing fat would`ve been an advantage."